Document:

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                                                                   EXHIBIT 10.21

                                  LEASE BETWEEN

          MICHELSON FARM-WESTFORD TECHNOLOGY PARK X LIMITED PARTNERSHIP

                                       AND

                            UNISPHERE SOLUTIONS, INC.

                                       FOR

        75,000 SQUARE FEET - PHASE II, MICHELSON FARM-WESTFORD TECHNOLOGY
                          PARK WESTFORD, MASSACHUSETTS

                                    I N D E X

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REFERENCE DATA

Paragraph 1.1                         Subject Referred To                              1
Paragraph 1.2                         Exhibits                                         4

ARTICLE II - PREMISES AND TERM:

Paragraph 2.1                         Premises                                         4
Paragraph 2.2                         Term                                             5

ARTICLE III - CONSTRUCTION:

Paragraph 3.1                         Initial Construction                             6
Paragraph 3.1.1                       Tenant's Work                                   10
Paragraph 3.1.2                       Tenant's Construction Work                      12
Paragraph 3.2                         Preparation of Premises for Occupancy           13
Paragraph 3.2.1                       Partial Occupancy and Rent Commencement         15
Paragraph 3.3                         General Provisions Applicable to Construction   16
Paragraph 3.4                         Representatives                                 16
Paragraph 3.5                         Force Majeure                                   17
Paragraph 3.6                         Arbitration by Architects                       17
Paragraph 3.7                         Warranty of Landlord's Work and Tenant's Work   18

ARTICLE IV - RENT:

Paragraph 4.1                         Rent                                            18
Paragraph 4.2                         Operating Cost Escalation                       18
Paragraph 4.3                         Payments                                        23
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ARTICLE V - LANDLORD'S COVENANTS:

Paragraph 5.1                         Landlord's Covenants during the Term            23
Paragraph 5.1.1                       Building Services                               23
Paragraph 5.1.2                       Additional Building Services                    23
Paragraph 5.1.3                       Repairs                                         24
Paragraph 5.1.4                       Quiet Enjoyment                                 24
Paragraph 5.1.5                       Intentionally Deleted                           24
Paragraph 5.1.6                       Landlord's Insurance                            24
Paragraph 5.1.7                       Landlord's Indemnity                            25
Paragraph 5.1.8                       Hazardous Materials                             25
Paragraph 5.1.9                       Tenant's Costs                                  26
Paragraph 5.2                         Interruptions                                   27

ARTICLE VI - TENANT'S COVENANTS:

Paragraph 6.1                         Tenant's Covenants during the Term              28
Paragraph 6.1.1                       Tenant's Payments                               28
Paragraph 6.1.2                       Repairs and Yielding Up                         28
Paragraph 6.1.3                       Occupancy and Use                               29
Paragraph 6.1.4                       Rules and Regulations                           29
Paragraph 6.1.5                       Compliance with Laws and Safety Appliances      29
Paragraph 6.1.6                       Assignment and Subletting                       30
Paragraph 6.1.7                       Indemnity                                       32
Paragraph 6.1.8                       Tenant's Liability Insurance                    33
Paragraph 6.1.9                       Tenant's Workmen's Compensation Insurance       33
Paragraph 6.1.10                      Landlord's Right of Entry                       33
Paragraph 6.1.11                      Loading                                         33
Paragraph 6.1.12                      Landlord's Costs                                34
Paragraph 6.1.13                      Tenant's Property                               34
Paragraph 6.1.14                      Labor or Materialmen's Liens                    34
Paragraph 6.1.15                      Changes or Additions                            34
Paragraph 6.1.16                      Holdover                                        35
Paragraph 6.1.17                      Hazardous Materials                             36
Paragraph 6.1.18                      Signs                                           37
Paragraph 6.1.19                      Tenant's Authority                              37
Paragraph 6.1.20                      Confidentiality                                 37
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ARTICLE VII - CASUALTY AND TAKING:

Paragraph 7.1                         Casualty and Taking                             38
Paragraph 7.2                         Reservation of Award                            41
Paragraph 7.3                         Additional Casualty Provisions                  41
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ARTICLE VIII - RIGHTS OF MORTGAGEE:

Paragraph 8.1                         Priority of Lease                               42
Paragraph 8.2                         Limitation on Mortgagees Liability              42
Paragraph 8.3                         Mortgagee's Election                            42
Paragraph 8.4                         No Prepayment or Modification                   42
Paragraph 8.5                         No Release or Termination                       43
Paragraph 8.6                         Continuing Offer                                43
Paragraph 8.7                         Submittal of Financial Statement                43

ARTICLE IX - DEFAULT:

Paragraph 9.1                         Events of Default                               44
Paragraph 9.2                         Tenant's Obligations After Termination          44

ARTICLE X - MISCELLANEOUS:

Paragraph 10.1                        Titles                                          45
Paragraph 10.2                        Notice of Lease                                 45
Paragraph 10.3                        Notices from One Party to the Other             45
Paragraph 10.4                        Bind and Inure                                  46
Paragraph 10.5                        No Surrender                                    46
Paragraph 10.6                        No Waiver, etc.                                 46
Paragraph 10.7                        No Accord and Satisfaction                      46
Paragraph 10.8                        Cumulative Remedies                             47
Paragraph 10.9                        Partial Invalidity                              47
Paragraph 10.10                       Right to Cure                                   47
Paragraph 10.11                       Estoppel Certificate                            48
Paragraph 10.12                       Waiver of Subrogation                           48
Paragraph 10.13                       Brokerage                                       49
Paragraph 10.14                       Parking/Traffic Personnel                       49
Paragraph 10.15                       Access                                          49
Paragraph 10.16                       Entire Agreement                                49
Paragraph 10.17                       Governing Law                                   49
Paragraph 10.18                       Additional Representations                      50
Paragraph 10.19                       Rooftop Communication Equipment                 50
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                     Date of Lease Execution: June 30, 2000

                                 REFERENCE DATA

1.1      SUBJECTS REFERRED TO:

         Each reference in this Lease to any of the following subjects shall
         incorporate the data stated for that subject in this Section 1.1.

         LANDLORD:                          Michelson Farm-Westford Technology
                                            Park X Limited Partnership

         MANAGING AGENT:                    The Gutierrez Company

         LANDLORD'S AND MANAGING            Burlington Office Park
         AGENT'S ADDRESS:                   One Wall Street
                                            Burlington, Massachusetts 01803

         LANDLORD'S REPRESENTATIVE:         John A. Cataldo

         LANDLORD'S CONSTRUCTION            Arturo J. Gutierrez, John A. Cataldo
         REPRESENTATIVES:                   or P. Agustin Rios

         TENANT:                            Unisphere Solutions, Inc.

         TENANT'S ADDRESS                   Prior to Term Commencement Date:
         (FOR NOTICE & BILLING):            Unisphere Solutions, Inc.
                                            5 Carlisle Road
                                            Westford, MA  01886

                                            After Term Commencement Date:
                                            Unisphere Solutions, Inc.
                                            10 Technology Park Drive
                                            Westford, Massachusetts 01886

         TENANT'S REPRESENTATIVE(S):        Robert T. Curtin

         TENANT'S CONSTRUCTION
         REPRESENTATIVE(S):                 Andrew Currie
<PAGE>   6
         BUILDING:                          Three (3) story building consisting
                                            of 75,000 rentable square feet
                                            constructed upon the land described
                                            on Exhibit A attached hereto (the
                                            "Lot") in accordance with the final
                                            Landlord's Plans and Tenant's Plans
                                            (as defined in Article III hereof,
                                            and any replacements thereof) and
                                            any alterations and additions
                                            thereto, including the Tenant's Work
                                            (as hereinafter defined). The legal
                                            description of the Lot is attached
                                            hereto as Exhibit A-1.

         RENTABLE FLOOR AREA OF             75,000 gross square feet, as further
         TENANT'S SPACE:                    described in Exhibit A

         TOTAL RENTABLE FLOOR AREA          75,000 gross square feet

         SCHEDULED TENANT'S DESIGN          August 31, 2000, subject to the
         COMPLETION DATE:                   provisions of Section 3.1

         SCHEDULED TERM                     March 31, 2001
         COMMENCEMENT DATE:

         OUTSIDE DELIVERY DATE:             Per Section 3.2

         TERM EXPIRATION DATE:              Ten (10) years following the Term
                                            Commencement Date determined in
                                            accordance with Section 3.2, subject
                                            to extension in accordance with
                                            Exhibit F.

         TERM:                              Ten (10) years, subject to extension
                                            in accordance with Exhibit F.

         FIXED RENT:                        Years 1-5:  $1,307,475.00/Year;
                                                        $108,956.25/Month;
                                                           ($17.43/RSF)
                                            Years 6-10: $1,531,725.00/Year;
                                                        $127,463.75/Month;
                                                           ($20.42/RSF)

                                       2
<PAGE>   7
         ANNUAL ESTIMATED OPERATING COSTS:
         (Including Real Estate Taxes)      $317,250.00/Year; $26,437.50/Month;
                                            ($4.23/RSF)

         ESTIMATED COST OF ELECTRICAL
         SERVICE TO TENANT'S SPACE
         [Excluded from Fixed Rent]:        See Exhibit D, Paragraph VII

         FIRST FISCAL YEAR FOR TENANT'S
         PAYING OPERATING COSTS             December 31, first occurring twelve
         ESCALATION YEAR ENDING:            (12) months after the Term
                                            Commencement Date.

         SECURITY DEPOSIT:                  Not Applicable

         GUARANTOR:                         Not Applicable

         PERMITTED USES:                    General office, light industrial
                                            research and development, laboratory
                                            and such other uses that are
                                            ancillary and accessory thereto.

         REAL ESTATE BROKERS:               Cushman & Wakefield of
                                            Massachusetts, Inc. and CB Richard
                                            Ellis

         PUBLIC LIABILITY INSURANCE:
         BODILY INJURY AND PROPERTY
         DAMAGE:

                                            Each Occurrence:  $1,000,000.00
                                            Aggregate:        $2,000,000.00

         SPECIAL PROVISIONS:         Parking:                  Per Section 10.14
                                     Option to Extend:         Per Exhibit F
                                     Allowances:               Per Exhibit M
                                     Guaranty of Completion:   Per Exhibit O
                                     Market Rent:              Per Exhibit P

                                       3
<PAGE>   8
1.2      EXHIBITS

         The Exhibits listed below in this Section are incorporated in this
         Lease by reference and are to be construed as part of this Lease:

         EXHIBIT A     Plans Showing Tenant's Space, the Lot and the Park
                       (including the Building Parking Area and Common Areas)

         EXHIBIT A-1   Legal Description of the Lot

         EXHIBIT B-1   Preliminary Base Building Plans

         EXHIBIT B-2   Base Building Outline Specifications

         EXHIBIT C-1   Form of Certificate of Substantial Completion

         EXHIBIT C-2   Form of Certificate of Final Completion

         EXHIBIT D     Landlord's Services

         EXHIBIT E     Rules and Regulations

         EXHIBIT F     Option to Extend

         EXHIBIT G     Tenant Estoppel Certificate

         EXHIBIT H     Intentionally Deleted

         EXHIBIT I     Park Covenants

         EXHIBIT J     Subordination, Non-Disturbance and Attornment Agreement

         EXHIBIT K     Form of Work Change Order

         EXHIBIT L     Definition of Cost of the Work

         EXHIBIT M     Allowances

         EXHIBIT N     Intentionally Deleted

         EXHIBIT O     Guaranty of Completion

         EXHIBIT P     Definition of Market Rent

         EXHIBIT Q     List of Existing Exclusives and Exclusions

         EXHIBIT R     Intentionally Deleted

         EXHIBIT S     Schedule

         EXHIBIT T     Form of Notice of Lease

         EXHIBIT U     Intentionally Deleted

                                   ARTICLE II
                                PREMISES AND TERM

2.1      PREMISES

         Subject to and with the benefit of the provisions of this Lease,
Landlord hereby leases to Tenant and Tenant leases from Landlord, the Rentable
Floor Area of Tenant's Space in the Building (hereinafter, the "Tenant's Space")
all as more particularly shown on Exhibit A attached hereto and made a part
hereof, together with the appurtenances described below and in Section 10.14 of
this Lease. Tenant's Space with such appurtenances, is hereinafter collectively
referred to as "the Premises".

         Tenant shall have, as appurtenant to the Premises, the right to use the
areas shown on the Plan attached as Part of hereto as Exhibit A as "Building
Parking Area", all subject to and as

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<PAGE>   9
further provided in Section 10.14 hereof and the Landlord's reserved expansion
rights set forth in Exhibit R.

         Tenant shall also have, as appurtenant to the Premises, the right to
use in common with others entitled thereto, subject to reasonable rules of
general applicability to tenants and owners of other lots in the park, commonly
known and referred to as the Michelson Farm-Westford Technology Park and shown
on the Plan of the Park attached hereto as part of Exhibit A (the "Park") from
time to time made by Landlord in accordance with Section 6.1.4 of which Tenant
is given written notice: (a) the common areas now or hereafter located at the
Park (the "Common Areas"), including, without limitation, the Common Areas shown
on the Plan of the Park attached hereto as part of Exhibit A, as such Common
Areas may be amended or modified by Landlord from time to time during the Term
hereof (b) all rights to access, all service areas, drainage of surface water
runoff, including, without limitation, storm drainage systems and detention
areas, (c) all grades, driveways, roadways, sidewalks and footways, lighting
systems and traffic flow patterns, (d) all parking areas designated as common or
visitors parking areas for use of the entire Park, if any, (e) all other rights
appurtenant to the Lot and the Building, (f) all means of access to and from the
Building to the Common Areas, including, without limitation, all sidewalks,
roads, driveways and the like, and (g) all utility lines, electricity, water and
sewage disposal.

         The Landlord and the Tenant acknowledge and agree that as a condition
of the Tenant's obligations under the Lease, the Tenant shall require a
leasehold title insurance policy insuring the Tenant's leasehold interest in the
Premises. Inasmuch as the lot plans, easements and related matters are being
finalized coterminously with the execution of the Lease, the Landlord covenants
with the Tenant that it shall cooperate with the Tenant during the construction
of the Premises to finalize a leasehold title insurance policy in form and
content reasonably acceptable to the Tenant. A loan policy will be generated by
the Landlord in connection with the construction financing to be secured by
Landlord and the Tenant's leasehold title policy shall be generated
simultaneously therewith. The cost of the Tenant's leasehold title insurance
policy shall be the sole responsibility of the Tenant.

The Tenant's leasehold title insurance policy shall insure Tenant's right of
access to the Premises and all easements required for drainage, utilities and
other matters necessary for the Tenant's operations in the Premises. It shall
also provide that the improvements to be located on the Lot, including without
limitation the parking, shall not interfere with, encroach upon, be prohibited
by or cause a violation of any easements which encumber the Lot.

2.2      TERM

         To have and to hold for a period (the "Term") commencing on the Term
Commencement Date determined in accordance with Section 3.2 (which said date is
at times being hereafter referred to as the "Commencement Date") and continuing
until the Term Expiration Date, unless sooner terminated as provided in Sections
3.2 or 7.1 or in Article IX, or unless extended pursuant to Exhibit F.

                                       5
<PAGE>   10
                                   ARTICLE III

                                  CONSTRUCTION

3.1      INITIAL CONSTRUCTION

         Landlord shall fully construct the base Building in accordance with the
preliminary base building plans, including, without limitation, floor plans,
elevations and site plan(s) (collectively, the "PBBP") and Base Building Outline
Specifications attached hereto as Exhibits B-1 and B-2, respectively (all of
such work being collectively referred to as the "Landlord's Work"). In the event
of differences between the PBBP or the Landlord's Plans (as hereinafter defined)
and the Base Building Outline Specifications, the Base Building Outline
Specifications shall govern and control until the Landlord's Plans (as
hereinafter defined) are prepared.

         A complete set of final base Building plans and construction drawings
and specifications, such drawings and specifications to include a detail
schedule of core base Building finish items such as, but not limited to,
carpets, doors, hardware, ceiling grids/tiles, lavatory fixtures, light
fixtures, window blinds, lobby finishes and paint/wall coverings (collectively,
the "Landlord's Plans") shall be prepared by Landlord, at its sole cost and
expense. Landlord and Tenant agree to work together with Landlord's architect,
Symmes Maini and McKee Associates, Inc. in order to achieve a design that meets
the standard set forth below. Furthermore, Landlord agrees to use good faith and
diligent efforts to deliver the Landlord's Plans to Tenant on or before July 15,
2000. Upon receipt, Tenant shall have seven (7) business days to comment upon
the Landlord's Plans. Landlord and Tenant shall use reasonable efforts to reach
agreement on the Landlord's Plans as soon thereafter as possible. In reaching
agreement, Landlord and Tenant shall each approve portions of the Landlord's
Plans that are in acceptable form and shall note their respective objections to
the portions that are unacceptable to each of them so as to enable Landlord to
continue construction and order materials in a timely manner. In the event that
Landlord's Plans conform with the PBBP, but Tenant does not approve the
Landlord's Plans within seven (7) business days of receipt thereof from
Landlord, then the Outside Delivery Date (as hereinafter defined) shall be
extended for a number of days equal to the number of Tenant Plan Delay Days, as
such term is hereinafter defined. The number of Tenant Plan Delay Days are
defined as and shall be calculated by determining the actual number of days as
certified by Landlord and its architect that the Term Commencement Date was
delayed by such Tenant's failure to approve the Landlord's Plans within the
required seven (7) business days. Landlord agrees to provide Tenant with written
notice of such determination, such notice to include reasonable detail
describing the cause of the delay and the number of Tenant Plan Delay Days as
certified by Landlord and its architect. If Tenant and Tenant's Architect (as
hereinafter defined) disagree with the existence or calculation of Tenant Plan
Delay Days as determined by Landlord and its architect, then Tenant shall,
within seven (7) business days of receipt of Landlord's notice, notify Landlord
of its disagreement, whereupon the dispute shall be determined pursuant to the
arbitration procedures described in Section 3.6 hereof.

         Landlord and Tenant hereby acknowledge and agree that, except as
otherwise set forth herein, following approval by Landlord and Tenant (which
shall be in writing as hereinafter provided), no amendments, modifications or
changes shall be made to the Landlord's Plans

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<PAGE>   11
without Tenant's prior written approval in each instance, which such approval
shall not be unreasonably withheld or delayed; provided, however, no such prior
approval of Tenant shall be required if the proposed amendments, modifications
or changes are, in Landlord's reasonable opinion (i) non-material in nature,
(ii) replaced by substantially equivalent or better items and at all times equal
to or better than that of the building located at 7 Technology Park Drive,
Westford, Massachusetts, and (iii) do not adversely affect the Premises. Without
limiting the foregoing, Landlord shall exercise reasonable efforts to provide
Tenant with prior written notice of all proposed amendments, modifications or
changes to the Landlord's Plans.

         A complete set of construction plans and specifications for Tenant's
Work (as hereinafter defined) shall be prepared by Tenant's Architect, as
hereinafter defined (collectively, the "Tenant's Plans"). The Tenant's Plans
shall be furnished to Landlord as herein provided. Landlord and Tenant hereby
acknowledge and agree that Tenant has selected Symmes Maini and McKee
Associates, Inc. to be "Tenant's Architect" for preparation of Tenant's Plans,
and the costs of services of such Tenant's Architect shall be borne solely by
Tenant (other than such portion of the cost to be paid by Landlord pursuant to
Exhibit M). Tenant's Architect (and Tenant's Representatives) shall be actively
involved in the design decisions and shall be allowed reasonable access to the
Lot and the Premises during construction to monitor Landlord's compliance with
the terms and provisions of this Lease. Landlord and Tenant hereby further agree
that Tenant shall be solely responsible for coordinating with Tenant's Architect
for the timely preparation of Tenant's Plans in accordance with the terms and
provisions of this Section 3.1. Attached as Exhibit S is a schedule (the
"Schedule") setting forth the respective dates by which Landlord and Tenant
anticipate that (i) Landlord's Plans shall have been delivered to and approved
by Tenant, (ii) Tenant's Plans shall have been delivered to and approved by
Landlord, and (iii) certain portions of Landlord's Work and Tenant's Work shall
be substantially completed. The parties agree to cooperate with each other and
to exercise reasonable efforts to complete the tasks described in the Schedule
by the respective dates set forth therein, Landlord and Tenant hereby further
agreeing that, unless otherwise expressly set forth herein, failure to meet any
of such dates on the Schedule shall not constitute a default or a delay of any
type hereunder.

         Tenant shall deliver the Tenant's Plans to the Landlord by not later
than the Scheduled Tenant's Design Completion Date, provided, however, that
Tenant furnishes to Landlord by not later than July 30, 2000 all information
relating to changes in the structural steel (i.e. rooftop equipment, floor and
roof openings, and other equipment exceeding 100 psf live load), any added doors
at the first floor exterior wall, and all information relating to any proposed
changes or additions to the base building rooftop HVAC equipment and to the
electrical service and switchgear. Tenant shall permit Landlord to review and
provide input during the preparation of Tenant's Plans. Upon receipt, Landlord
shall have five (5) business days to comment upon the Tenant's Plans. Landlord
and Tenant shall use reasonable efforts to reach agreement on the Tenant's Plans
within ten (10) days of Tenant's receipt of Landlord's comments thereto. In
reaching such agreement, Landlord and Tenant shall each approve portions of
Tenant's Plans that are acceptable and shall note their respective objections to
the portions that are unacceptable to each of them so as to enable Landlord to
continue construction and order materials in a timely manner. In connection with
Landlord's review of the Tenant's Plans, or if Tenant fails to deliver

                                       7
<PAGE>   12
Tenant's Plans (or any modifications thereto) by the date set forth above,
Landlord may require by prompt written notice to Tenant (i) modifications in
Tenant's Plans (i.e. if Tenant's Plans are not compatible with Landlord's
Plans), and/or (ii) an adjustment in the Outside Delivery Date (such adjustment
to be determined by Landlord in its reasonable judgment). Landlord's notice to
Tenant shall include reasonable detail describing the cause of the adjustment
and/or the extent of the incompatibility with reasonable specificity. Any such
extension in time, whether mutually agreed to by Landlord and Tenant or
determined by their respective architects in the event of dispute pursuant to
Section 3.6, shall result in Tenant's Plan Delay Days as hereinbefore
determined. In addition, Landlord will not approve Tenant's Plans which involve
any construction, alterations or additions requiring unusual expense to readapt
the Premises to normal office use on the Term Expiration Date, unless Tenant
first gives assurances acceptable to Landlord that such readaptation shall be
made prior to such termination without expense to Landlord. Notwithstanding the
preceding sentence, Landlord hereby acknowledges and agrees that such
cafeterias, laboratories and other initial Tenant improvements described in
Landlord's Plans or Tenant's Plans shall not require removal by Tenant at the
expiration of the Term and such initial Tenant improvements shall be allowed to
remain without additional cost to Tenant. All revisions and modifications to the
Tenant's Plans shall be made promptly by Tenant and revised sets of Tenant's
Plans shall be forthwith furnished to Landlord upon Tenant's receipt thereof,
Landlord hereby agreeing to inform Tenant during the plan approval process and,
in any event, prior to the installation thereof, of any such items that may
require unusual expense to readapt the Premises as aforesaid. All revisions and
modifications to the Tenant's Plans shall be made promptly by Tenant and revised
sets of Tenant's Plans shall be forthwith furnished to Landlord upon Tenant's
receipt thereof. Landlord and Tenant hereby further agree to acknowledge in
writing when final approval by Landlord and Tenant of Tenant's Plans (and
Landlord's Plans) has occurred. No changes or modifications to Tenant's Plans or
Tenant's Work being constructed by Landlord pursuant thereto shall be made
without Tenant's consent, such consent not to be unreasonably withheld or
delayed by Tenant.

         Landlord shall have fifteen (15) days after final approval of Tenant's
Plans and Landlord's receipt of final and complete sets of approved Tenant's
Plans, which such final approval has been acknowledged in writing by Landlord
and Tenant as aforesaid, to price the cost of Tenant's Work (as hereinafter
defined) in accordance with the last paragraph of Section 3.1.1.

         Landlord and Tenant shall cooperate during the above time periods so
that each party makes the other aware of their progress with respect to the
foregoing plans, selections and pricing, as well as timing, availability or cost
constraints of Tenant's selections or specifications and proposed alternates.

         Landlord shall cause the Premises to be completed in accordance with
Landlord's Plans and Tenant's Plans, all of such work to be performed by
Landlord's general contractor, Gutierrez Construction Co., Inc. After final
approval of Landlord's Plans and Tenant's Plans by Landlord and Tenant, the
Tenant may request changes to Landlord's Work or Tenant's Work (as applicable)
by altering, adding to, or deducting from Landlord's Work or Tenant's Work (as
applicable) as set forth in the agreed form of Landlord's Plans or Tenant's
Plans, as applicable

                                       8
<PAGE>   13
(each such requested change is referred to herein as a "Change Order"). A Change
Order requested by Tenant in Landlord's Work (or in Tenant's Work as such term
is defined in Section 3.1.1 hereof) which affects Landlord's Work may also
necessitate an adjustment in the Outside Delivery Date (as defined in Section
3.2 hereof) and may result in Tenant Alteration Delay Days (as hereinafter
defined), in accordance with and subject to the terms and conditions set forth
below. Landlord shall notify Tenant in writing if such requested Change Order
shall result in Tenant Alteration Delay Days, and therefore an adjustment in the
Outside Delivery Date. In addition, Landlord agrees to provide Tenant, upon
Tenant's request, with sufficient itemization and back-up documentation to
facilitate analysis and to confirm the cost of any such changes in the
Landlord's Work or the Tenant's Work initiated by Tenant. Tenant shall pay to
Landlord an amount equal to the actual cost (as defined in Section 3.1.1 hereof)
of Landlord's Work, including the costs of any such changes initiated by Tenant,
less any appropriate credits for any Landlord's Work deleted, (hereinafter, the
"Net Additional Cost of Landlord's Work"). The Net Additional Cost of Landlord's
Work shall be due and payable to Landlord in the manner provided for in Section
3.1.1 hereof.

         In the event that Tenant requests a Change Order which would, due to
materials or equipment having long delivery times or due to resulting sequencing
delays, and notwithstanding Landlord's diligent efforts, result in a delay in
the Term Commencement Date, then Tenant shall be deemed to have agreed that it
will pay Fixed Rent (as hereinafter provided in Section 4.1) and additional rent
hereunder for a number of days equal to the actual number of days (the "Tenant
Alteration Delay Days") as certified by Landlord and its architect, and agreed
to by Tenant and Tenant's Architect as hereinafter provided, by which the Term
Commencement Date would be delayed by such alterations or additions, giving due
consideration to Landlord's obligation to use diligent efforts to accelerate
construction to make up for lost time due to delays. Landlord agrees to promptly
provide Tenant with written notice of such determination, such notice to include
reasonable detail describing the cause of the delay and the number of Tenant
Alteration Delay Days as certified by Landlord and its architect. Should Tenant
and Tenant's Architect disagree with the calculation of Tenant Alteration Delay
Days as hereinabove determined, then such disagreement shall be resolved
pursuant to the provisions of Section 3.6 hereof.

         All Tenant improvements, changes and additions shall be part of the
Premises (and shall remain therein at the end of the Term), except for Tenant's
business fixtures, equipment and personal property (which such personal property
shall include, without limitation, demountable partitions, equipment and
telephone or computer systems), all of which fixtures, equipment and personal
property shall remain the property of the Tenant and shall be removed at the
expiration of the Term; and such other items shall be removed or left as the
Landlord and Tenant agree in writing at the time of Landlord's approval of the
plans and specifications therefor. Tenant agrees to repair, at its sole cost and
expense, any damage to the Premises caused by any such removal by Tenant in
accordance with this paragraph. As aforesaid, notwithstanding the foregoing
provisions on this paragraph, Tenant shall not be required to remove cafeterias,
laboratories or other initial Tenant improvements described in Landlord's Plans
or Tenant's Plans upon expiration of the Term and such initial Tenant
improvements shall be allowed to remain without additional cost to Tenant.

                                       9
<PAGE>   14
3.1.1    TENANT'S WORK.

         Landlord and Tenant agree that Gutierrez Construction Co., Inc. will
construct the tenant improvements set forth on the Tenant's Plans (hereinafter
"Tenant's Work") with respect to the Premises at cost (as hereinafter defined),
plus an amount for general conditions of seven percent (7%) (not to exceed
$210,000.00) and a Landlord's contractor's fee of six percent (6%) of such
aggregate cost, less an amount equal to the allowances set forth on Exhibit M
attached hereto and made a part hereof. In order to provide for payment by
Tenant of the cost of Tenant's Work, the Net Additional Cost of Landlord's Work,
and any additional costs due to Change Orders provided for hereunder, less said
allowances, Tenant expressly covenants with Landlord that Tenant agrees to
deposit into an interest-bearing account to be established and maintained by
Landlord's mortgagee (or such other escrow agent mutually agreed upon by the
parties) by June 30, 2000, $2,250,000.00. Tenant's deposit into escrow shall be
released by Landlord's construction mortgagee, as escrow agent, to Landlord, or
its contractors, as the case may be, upon Substantial Completion of Landlord's
Work and Tenant's Work, as provided in Section 3.2 hereof. Tenant shall be
responsible for payment of escrow fees, if any, incurred by Landlord or Tenant
in connection with such escrow account. In addition, Tenant shall be responsible
for interest costs and one-half percent (1/2 %) commitment fee incurred by
Landlord in connection with its financing of the cost of Tenant's Work and
Change Orders, as applicable. Any and all interest earned on the escrowed funds
shall be payable to Tenant at such time as the escrow is released by Landlord's
mortgagee, or such other mutually agreed upon escrow agent as aforesaid. It is
acknowledged and agreed by Landlord and Tenant that Landlord's mortgagee shall
have no right to set off such escrow account against any of Landlord's
obligations with its mortgagee. In the event that this Lease is terminated by
Tenant pursuant to the provisions of Section 3.2, Landlord's mortgagee shall
release all amounts in the escrow account (including interest) to Tenant.

        The total estimated cost to complete the Tenant's Work under this Lease
is three million dollars ($3,000,000.00) or forty dollars ($40.00) per square
foot (hereinafter, the "Total Estimated Cost"). To the extent that the actual
cost of the Tenant's Work, Net Additional Cost of Landlord's Work and/or Change
Orders, as determined by this Article, is greater than the Total Estimated Cost,
Landlord shall provide Tenant with written notice of such fact together with
reasonable supporting information. In such event Landlord shall provide Tenant
with monthly construction requisitions for the construction of the portion of
the Tenant's Work, Net Additional Cost of Landlord's Work and/or Change Orders
in excess of the Total Estimated Cost, and Tenant agrees to deposit into said
escrow account monthly the total amount of any such monthly requisitions based
on a percentage of completion basis within five (5) business days of receipt
thereof, and any such additional deposits made by Tenant shall be released to
Landlord at the time and in the manner as the deposit noted above.

         Landlord and Tenant hereby further acknowledge and agree to enter into
a formal escrow agreement with Landlord's mortgagee or such other escrow agent
as aforesaid, to implement the foregoing arrangements prior to June 30, 2000.
Such escrow agreement shall be in form and substance as executed in connection
with that certain lease dated March 31, 2000 and

                                       10
<PAGE>   15
executed by and between the parties regarding Phase I of the Building consisting
of 150,000 square feet (the "Phase I Lease").

         Each requisition shall include copies of all subcontractor's and
supplier's applications for payment and satisfactory evidence of payment of all
previous invoices submitted by subcontractors and suppliers. In addition,
Landlord's architect shall certify that the subject work specified in each of
such monthly requisitions has been substantially completed, and a copy of such
certification shall accompany each requisition furnished to Tenant hereunder. In
no event shall any of such costs due and payable hereunder remain unpaid by
Tenant as of the Term Commencement Date. Tenant and Tenant's Architect shall
have the opportunity to inspect the subject work and to confirm the foregoing
certification by Landlord's architect, and any disputes following such
inspection(s) shall be determined pursuant to Section 3.6 hereof.

         For purposes hereof, Landlord and Tenant further agree that the
certification of cost by Gutierrez Construction Co., Inc. shall be based on the
definition of cost as more particularly set forth in Exhibit L hereto. Any
changes to the Tenant's Plans after the approval of the Tenant's Plans (and any
changes to Landlord's Plans after the approval thereof as set forth in Section
3.1 above) shall be in accordance with the form of Work Change Order attached
hereto as Exhibit K.

         If Tenant informs Landlord in writing of its election to require that
Landlord bid out the major contracts in the pricing of the cost of Tenant's Work
(specifically excluding Landlord's Work hereunder), Landlord agrees to obtain
three (3) qualified bids from subcontractors selected from a master list of
subcontractors mutually prepared and agreed upon by Landlord and Tenant prior to
the soliciting of bids for any item of Tenant's Work exceeding twenty-five
thousand dollars ($25,000.00). The subcontractor selected for the performance of
the work shall be, subject to Tenant's right to select the final bidder as
hereinafter provided, the subcontractor with the lowest bid price; provided,
however, that if Landlord, in its reasonable judgment, determines that due to
changed conditions (such as increased work commitments on the part of the
respective subcontractor, or other pertinent factors) the selection of such low
bidder could result in Subcontractor Delay Days (as hereinafter defined), then
Landlord shall provide written notice (a "Landlord's Subcontractor Notice")
thereof to Tenant, which notice shall identify the low bidder and next lowest
bidder and indicate the number of Subcontractor Delay Day(s) that would result
from selection of the low bidder (giving due consideration of Landlord's
obligations to use diligent efforts to accelerate construction to make up for
lost time to delays). Tenant shall have four (4) business days upon receipt of
such Landlord's Subcontractor Notice to notify Landlord that either (i) Landlord
should proceed with the original low bidder (in which event the Outside Delivery
Date shall be extended for the number of days (the "Subcontractor Delay Day(s)")
equal to the number of Subcontractor Delay Days indicated in Landlord's
Subcontractor Notice), or (ii) Landlord's selection of the next lowest bidder is
acceptable to Tenant (in which event the Outside Delivery Date shall not be
extended), or (iii) Landlord shall select the third bidder if Tenant, in its
reasonable discretion, determines that the third bidder should be the one
selected for performance of the work (in which event Landlord shall notify
Tenant if such selection shall result in Subcontractor Delay Days and if so, the
number of delay days, whereupon Tenant shall have an additional four (4)
business days to advise Landlord as to its selection). If Tenant so selects such
third bidder, then Landlord shall proceed with such bidder and the Outside
Delivery

                                       11
<PAGE>   16
Date shall be extended for the number of Subcontractor Delay Days indicated in
Landlord's notice. Failure by Tenant to respond within either of said four (4)
day periods shall be deemed to constitute acceptance by Tenant of Landlord's
selection of the next lowest bidder. Landlord agrees to use reasonable efforts
to notify Tenant simultaneously or forthwith upon Tenant's notification to
Landlord as to its election set forth in (i), (ii) or (iii) above, if Landlord
has knowledge or a reasonable basis to believe that a Subcontractor Delay Day(s)
will likely result due to Landlord's notification requirements hereunder,
regardless of whether or not Tenant elects to proceed with the original lowest
bidder or not. In addition, in the event that Landlord and Tenant are unable to
agree on the cost of any portion of said work, any disagreement shall be
resolved pursuant to the provisions of Section 3.6 hereof.

         Upon commencement of the Tenant's Work, Landlord and Tenant hereby
further agree, each acting reasonably and in good faith, to attend and
participate in weekly construction meetings with Landlord's general contractor's
construction manager(s) during such construction process.

3.1.2    TENANT'S CONSTRUCTION WORK.

         Tenant agrees that any construction included in Tenant's Plans which
Tenant specifies to be done by itself or its contractors (hereinafter referred
to as "Tenant's Construction Work"), which shall include, for example, Tenant's
installation of furnishings, lab equipment, IT/MIS, security and later changes
or additions, shall be completed by and coordinated with any work being
performed by Landlord in such manner as to maintain harmonious labor relations
and not materially damage the Premises or Lot or materially interfere with the
operation of the Building or with any of Landlord's construction work hereunder,
including but not limited to the construction of the Landlord's Work and
Tenant's Work. Tenant (including its contractors, agents or employees) shall
have access to the Premises and may perform Tenant's Construction Work prior to
the Scheduled Term Commencement Date and prior to the commencement of the Term
so as to prepare the Premises for occupancy by Tenant ("Pre-Occupancy"),
provided that (i) Tenant's contractors, agents or employees work in a harmonious
labor relationship with Landlord's general contractor, (ii) reasonable prior
written notice is given to Landlord's general contractor specifying the work to
be done, and (iii) no work, as reasonably determined by Landlord, shall be done
or fixtures or equipment installed by Tenant in such manner as to materially
interfere with the completion of Landlord's Work and the Tenant's Work being
done by or for Landlord on the Premises. During the period of preoccupancy of
the Premises by Tenant in connection with Tenant's Construction Work prior to
the commencement of the Term, no Fixed Rent or additional rent or other charges
shall accrue or be payable, but otherwise such preoccupancy shall be subject to
all the terms, covenants and conditions contained in this Lease.

3.2      PREPARATION OF PREMISES FOR OCCUPANCY.

         Landlord shall perform the construction work set forth in the
Landlord's Plans and the Tenant's Plans, and, therefore, Landlord agrees to use
diligent efforts to have the Premises ready for occupancy on the Scheduled Term
Commencement Date.

                                       12
<PAGE>   17
         Landlord and Tenant agree that time is of the essence, and Landlord
agrees to use diligent efforts to accelerate construction to make up for time
lost due to any delay. Unless sooner terminated by Tenant pursuant to the
provisions of Section 3.2, the Term of this Lease shall commence on the date the
Premises are deemed ready for occupancy as set forth below (the "Term
Commencement Date").

         The Premises shall be deemed "ready for occupancy" on the earlier of:

         (a) the date on which Tenant occupies all or any portion of the
Premises for the Permitted Uses (except this shall not include periods of
Pre-Occupancy by Tenant as set forth in Section 3.1.2); or

         (b) (1) the date on which the construction of all of the Landlord's
Work and the Tenant's Work is Substantially Completed, as defined below, and (2)
Landlord has delivered to Tenant copies of all permits and approvals (the
"Permits") required to be obtained from any governmental agency either in
connection with the (i) construction of the Building or the Park, or any part
thereof, or (ii) prior to occupancy of the Premises by Tenant, including,
without limitation, a permanent certificate of occupancy from the Town of
Westford or a temporary certificate of occupancy from the Town of Westford which
allows Tenant to use and occupy the Premises, and which temporary certificate of
occupancy is not conditional on the performance of any work other than the Punch
List Work as defined below, except that such Permits shall not be required as a
condition of Substantial Completion if Landlord is unable to secure the same due
solely to Tenant's failure to complete Tenant's Construction Work as specified
in Section 3.1.2 above (which such date, subject to additional terms and
provisions of this Section 3.2, shall hereinafter be referred to as the date of
"Substantial Completion" or which such work shall hereinafter be referred to as
"Substantially Completed"). In any event, notwithstanding the achievement of
Substantial Completion, all Punch List Work shall be completed by no later than
thirty (30) days after the date of Substantial Completion, except as hereinafter
provided.

         An AIA Certificate of Substantial Completion by the Landlord's
architect and approved by Tenant's Architect (which such Certificate shall be in
the form attached hereto as Exhibit C-1), shall evidence the Landlord's
determination that it has performed all such obligations, except for completing
the landscaping work and completing the final paving course, and minor items
stated in such Certificate to be incomplete or not in conformity with such
requirements, or will not materially interfere with Tenant's use or occupancy of
the Premises and all of which work shall be identified and specified in the
Certificate of Substantial Completion (collectively such landscaping work,
finish paving course work and minor items are referred to herein as the "Punch
List Work") shall be promptly completed. Tenant shall have the right within
fifteen (15) days after Tenant's receipt of said Certificate of Substantial
Completion to notify Landlord of its disagreement with said Certificate and to
identify additional items of Punch List Work, all of which shall be completed by
Landlord within thirty (30) days after notice thereof from Tenant.

         If weather materially and adversely interferes with Landlord's ability
to finish the final course of paving and outside work or such other Punch List
Work, which such work does not materially interfere with Tenant's occupancy, and
the operation of Tenant's business therein, said

                                       13
<PAGE>   18
work can be completed by Landlord reasonably thereafter, so long as such delay
does not and will not interfere with or prevent Landlord from obtaining a
certificate of occupancy upon completion of all other work herein described.

         Notwithstanding the foregoing, in the event that the Punch List Work is
not completed by Landlord on or before such date which is six (6) months
following the date of Substantial Completion, then Tenant shall have the right,
but not the obligation, to complete the Punch List Work and charge the Landlord
the difference, if any, between the costs reasonably incurred by Tenant in
completing the same, provided that at least thirty (30) days prior written
notice has been provided to Landlord, its mortgagee (of whose address Tenant has
been given written notice) and The Gutierrez Company (as guarantor under the
Guaranty of Completion to be furnished to Tenant upon execution of this Lease,
such guaranty to be in the form attached hereto as Exhibit O) and Landlord shall
have not cured (or commenced to cure and is not prosecuting curing of the same
to completion with due diligence) the same. Landlord agrees to reimburse Tenant
pursuant to the provisions of 10.10(b) hereof and shall be entitled to such
offset rights as set forth therein.

         After Landlord has completed all Landlord's Work and Tenant's Work,
including all Punch List Work, Landlord's architect shall forward to Tenant its
Certificate of Final Completion, such Certificate to be in the form attached
hereto as Exhibit C-2. In addition, promptly after completion of all such work,
including all Tenant's Construction Work by Tenant, Landlord shall forward to
Tenant a final certificate of occupancy from the Town of Westford.

         The phrase "Tenant's Delay" shall mean the aggregate number of days
(excluding any days of delay caused by or resulting from Force Majeure) equal to
the actual number of days that, notwithstanding its diligent and good faith
efforts to complete construction by the Scheduled Term Commencement Date, the
Landlord is delayed in completing its construction by the Scheduled Term
Commencement Date due to (i) the failure of the Tenant to deliver the Tenant's
Plans (or modifications thereto) to Landlord on the dates established pursuant
to Section 3.1 hereof, or (ii) a delay caused by Tenant performing the Tenant's
Construction Work pursuant to Section 3.1.2 hereof, or (iii) the number of
Subcontractor Delay Days pursuant to Section 3.1.1 hereof, or (iv) a delay or
stoppage requested in writing by Tenant, or (v) the number of Tenant Alteration
Delay Days resulting from Change Orders requested by Tenant pursuant to Section
3.1 hereof, or (vi) the number of Tenant Plan Delay Day(s) pursuant to Section
3.1 hereof, then the Term Commencement Date shall be deemed to have occurred on
the date, as certified by Landlord and its architect, and agreed upon by
Tenant's Architect, that Substantial Completion would have occurred had there
not occurred such Tenant's Delay, calculated by determining the number of days
of Tenant's Delay as aforesaid, giving consideration to Landlord's obligation
under the second paragraph of this Section 3.2 to accelerate to make up for time
lost due to any delays. Landlord agrees to promptly provide Tenant with written
notice of such Tenant's Delay promptly after the occurrence of such Tenant's
Delay, such notice to include reasonable detail describing the cause of the
delay as certified by Landlord's architect.

         Notwithstanding the foregoing provisions, if the Premises are not
deemed ready for occupancy on or before the Outside Delivery Date (as defined
below) for whatever reason,

                                       14
<PAGE>   19
Tenant may elect (i) to cancel this Lease at any time thereafter while the
Premises are not deemed ready for occupancy by giving notice to Landlord of such
cancellation which shall be effective ten (10) days after such notice, unless
within such ten (10) day period Landlord delivers the Premises ready for
occupancy as defined herein, in which event such notice of cancellation shall be
rendered null and void and of no further force or effect, or (ii) to enforce
Landlord's covenants to construct the Premises in accordance with the terms of
this Lease. In the event Tenant elects to enforce Landlord's agreement to
construct the Premises in accordance with this Lease, Tenant shall also have the
right to terminate this Lease if Landlord fails to complete the Premises within
the period of time set by any court of competent jurisdiction for such work to
be completed, or within such additional period of time from the date of
Landlord's default as may be mutually agreed to by Landlord and Tenant.
Notwithstanding any provisions of this Lease to the contrary, in the event that
the Premises are not deemed ready for occupancy on or prior to such date which
is ninety (90) days following the Scheduled Term Commencement Date (as such date
may be extended for reasons due to Force Majeure and/or to Tenant's Delay), then
Tenant may elect to receive from Landlord as liquidated damages an abatement of
Fixed Rent, less the Annual Estimated Operating Costs (following commencement of
rental obligations pursuant to Section 4.1) equal to one hundred percent (100%)
of the Fixed Rent, less the Annual Estimated Operating Costs, for each day the
Tenant's Work and Landlord's Work is not Substantially Completed ninety (90)
days beyond the Scheduled Term Commencement Date (as such date may be extended
as aforesaid). The foregoing remedies shall be Tenant's sole and exclusive
remedies for not having the Premises completed on or before the Outside Delivery
Date.

         For purposes hereof, the Outside Delivery Date shall be deemed to refer
to that certain date which is sixty (60) days following the Scheduled Term
Commencement Date, as such date may be extended for a period equal to that of
(i) any delays due to Force Majeure as defined in Section 3.5 hereof, (ii) the
number of delay days caused by a Tenant's Delay as hereinbefore determined;
provided, however, that there shall be no extensions for the matters set forth
in clause (i) above (specifically excluding the matters set forth in clause (ii)
above) for more than forty-five (45) days in the aggregate.

3.2.1    PARTIAL OCCUPANCY AND RENT COMMENCEMENT.

         If the entire Premises are not ready for occupancy on the Scheduled
Term Commencement Date, the Tenant may elect, but shall have no obligation to,
occupy any portion or portions of the Premises which are ready for occupancy
when, in Landlord's opinion, it can be done without material interference with
remaining work. In such event, Tenant agrees not to materially interfere with
Landlord's construction of the Premises. In the event Tenant elects to take
occupancy of a portion of the Premises, that portion shall be deemed ready for
occupancy as to said portion on the date of occupancy of such portion and
Tenant's obligation to pay Fixed Rent and additional rent shall commence on said
date pro rata based on the square footage occupied compared to the total square
footage in the Premises. The foregoing provisions of this Section 3.2.1 shall
not apply to the rights of Tenant set forth in Section 3.1.2 hereof.

3.3      GENERAL PROVISIONS APPLICABLE TO CONSTRUCTION

                                       15
<PAGE>   20

         All construction work required or permitted by this Lease, whether by
Landlord or by Tenant (or their respective subcontractors), shall be done in a
good and workmanlike manner and in compliance with Landlord's Plans and Tenant's
Plans and all applicable laws and all lawful ordinances, regulations and orders
of governmental authority and insurers of the Building. Either party may inspect
the work of the other at reasonable times and shall promptly give notice of
observed defects. Notice of said defects shall be in writing and shall be
rectified by Landlord or Tenant, as the case may be, within thirty (30) days of
the original date of notice. Except as otherwise provided in Section 3.7 hereof,
failure to provide notice hereunder shall not be the basis for any liability or
for injury or damage caused by such defect of or waiver of right to cause any
defect to be corrected.

3.4      REPRESENTATIVES

         Landlord hereby acknowledges and agrees that only the following
persons, Robert T. Curtin, Andrew Currie or Stephen Hassell, or any successors
to either of them holding the same title or any other person delegated the
authority from either of them in writing (hereinafter "Tenant's Construction
Representatives") have the authority to act on Tenant's behalf and represent
Tenant's interest with respect to all matters requiring Tenant's action in this
Article. No consent, authorization or other action by Tenant with respect to
matters set forth in this Article shall bind Tenant unless in writing and signed
by one of the aforementioned persons. Landlord hereby expressly recognizes and
agrees that no other person claiming to act on behalf of Tenant is authorized to
do so. If Landlord complies with any request or direction presented to it by
anyone claiming to act on behalf of Tenant who does not have the title and
position mentioned above, such compliance shall be at Landlord's sole risk and
responsibility and shall not in any way alter or diminish the obligations and
requirements created and imposed by this Article, and Tenant shall have the
right to enforce compliance with this Article without suffering any waiver or
abrogation of any of its rights hereunder.

         Tenant hereby acknowledges and agrees that only the following persons,
Arturo J. Gutierrez, John A. Cataldo or P. Agustin Rios or any successors to
either of them holding the same title or any other person delegated the
authority from either of them in writing (hereinafter "Landlord's Construction
Representatives") have the authority to act on Landlord's behalf and represent
Landlord's interests with respect to all matters requiring Landlord's action in
this Article. No consent, authorization or other action by Landlord with respect
to matters set forth in this Article shall bind Landlord unless in writing and
signed by one of the aforementioned persons. Tenant hereby expressly recognizes
and agrees that no other person claiming to act on behalf of Landlord is
authorized to do so. If Tenant complies with any request or direction presented
to it by anyone claiming to act on behalf of Landlord who does not have the
title and position mentioned above, such compliance shall be at Tenant's sole
risk and responsibility and shall not in any way alter or diminish the
obligations and requirements created and imposed by this Article, and Landlord
shall have the right to enforce compliance with this Article without suffering
any waiver or abrogation of any of its rights hereunder.

3.5      FORCE MAJEURE.

                                       16
<PAGE>   21

         As used in this Article and elsewhere in the Lease, "Force Majeure"
shall mean a time extension equal to that of any delays when the party required
to perform the respective obligation is prevented from doing so, despite the
exercise of reasonable diligence, and such delay is caused by: (i) Acts of God,
(ii) changes in government regulations, (iii) casualty, (iv) strike or other
such labor difficulties, (v) unusual weather conditions, (vi) unusual scarcity
of or inability to obtain supplies, parts or employees to furnish such services,
or (vii) other acts reasonably beyond Landlord's control, but in no event shall
the term include economic or financing difficulties. Landlord shall provide
Tenant with written notice of the occurrence of a Force Majeure event promptly
after the occurrence thereof, and shall comply with its respective obligation(s)
as soon as the cause for the delay has (have) been eliminated. As hereinbefore
provided in Section 3.2, extensions due to Force Majeure shall be limited to
forty-five (45) days in the aggregate.

3.6      ARBITRATION BY ARCHITECTS.

         Whenever there is a disagreement between the parties with respect to
construction by Landlord of Landlord's Work or Tenant's Work, such disagreement
shall be definitively determined by the following procedure: Each of Landlord
and Tenant shall appoint one (1) independent architect (which such architect may
be Landlord's Architect and Tenant's Architect referenced in section 3.1 above),
such two (2) architects will then (within five (5) days of their appointment)
appoint a third independent architect licensed in the Commonwealth of
Massachusetts with not less than ten (10) years experience. Each architect shall
establish within ten (10) days of their appointment the matter in dispute. In
case of any dispute with respect to dollar amounts or lengths of time or dates
such as the date of Substantial Completion, the dollar amount or length of time
or date shall be the average of the two closest determinations by the three (3)
architects, with the determination of the architect which was not closest to
another architect's determination excluded from such calculation. In case of any
dispute not involving dollar amounts or lengths of time or dates (i.e. the
approval of plans) the determination by at least two (2) of the three (3)
architects shall be required in order to resolve the matter in dispute. Landlord
and Tenant shall each bear the cost of the architect selected by them
respectively and shall share equally the cost of the third architect. During
such arbitration period, the parties agree to cooperate with one another so as
to proceed with construction and with their respective obligations hereunder in
a timely manner. Each determination under this Section 3.6 shall be binding upon
Landlord and Tenant.

3.7      WARRANTY OF LANDLORD'S WORK AND TENANT'S WORK.

         Notwithstanding the provisions of Section 3.3, Landlord hereby warrants
and guarantees that the Landlord's Work and the Tenant's Work shall be free from
defects in workmanship and materials for a period of one (1) year after the Term
Commencement Date or such later date upon which all such work has been completed
(including Punch List Work). Upon the expiration of said one (1) year period,
Landlord shall assign to Tenant any and all warranties and guarantees with
respect to Landlord's Work and Tenant's Work and, to the extent that any such
warranties and guarantees are not assignable, Landlord agrees to enforce the
same for the benefit of Tenant, at Tenant's sole cost and expense. Tenant shall
not be responsible to pay for any such warranties of less than one (1) year
duration or enforcement by Landlord against its own employees or

                                       17
<PAGE>   22
against Gutierrez Construction Co., Inc. or against any of its other affiliates
(including their respective employees). Landlord agrees to repair, at its sole
cost and expense any latent defects in Landlord's Work or Tenant's Work promptly
after receipt of notice therefrom from Tenant, provided that such notice from
Tenant is received by Landlord on or before such date which is three (3) years
after the Term Commencement Date or such later date upon which all such work has
been completed (including Punch List Work). In connection therewith, Tenant
shall notify Landlord promptly after it becomes aware of any such latent
defects. Any repairs or replacements or alterations to Landlord's Work or
Tenant's Work after said initial one (1) year period, and any work required
because of latent defects after said three (3) year period, shall be chargeable
to Tenant in accordance with and subject to the provisions of Section 4.2
hereof.

                                   ARTICLE IV
                                      RENT

4.1      RENT

         Tenant agrees to pay, without any offset or reduction, except as
expressly set forth herein, Fixed Rent equal to 1/12th of the annual Fixed Rent
set forth in Section 1.1 in equal installments in advance on the first day of
each calendar month included in the Term; and for any portion of a calendar
month occurring at the beginning or end of the Term, at the rate payable for
such portion in advance.

4.2      OPERATING COST ESCALATION

         With respect to the First Fiscal Year for Tenant's Paying Operating
Cost Escalation, or fraction thereof, and any Fiscal Year or fraction thereafter
during the Term, Tenant shall pay to Landlord, as additional rent, Operating
Cost Escalation (as defined below), if any, on or before the thirtieth day
following receipt by Tenant of Landlord's Statement (as defined below). As soon
as practicable after the end of each Fiscal Year ending during the Term and
after Lease termination, Landlord shall render a statement ("Landlord's
Statement") in reasonable detail and according to generally accepted accounting
principles, consistently applied, certified by Landlord, and showing for the
preceding Fiscal Year or fraction thereof, as the case may be, "Landlord's
Operating Costs,"

         EXCLUDING the interest and amortization on mortgages for the Building
and Lot or leasehold interests therein and the cost of special services rendered
to tenants (including Tenant) for which a special charge is made,

         BUT INCLUDING, without limitation: real estate taxes on the Building,
the Lot and the Common Areas of the Park (including without limitation the sewer
treatment plant servicing the Park); installments and interest on assessments
for public betterments or public improvements; expenses of any proceedings for
abatement of taxes and assessments with respect to any Fiscal Year or fraction
of a Fiscal Year; premiums for insurance required to be maintained by Landlord
pursuant to this Lease; compensation and all fringe benefits, workmen's
compensation, insurance premiums and payroll taxes paid by Landlord to, for or
with respect to all persons engaged in the

                                       18
<PAGE>   23
operating, maintaining, or cleaning of the Building and Lot; steam, water,
sewer, electric, gas, telephone, and other utility charges not billed directly
to tenants by Landlord or the utility, but not including the cost to Landlord of
electricity furnished for lighting, electrical facilities, equipment, machinery,
fixtures and appliances used by Tenant in Tenant's Space (other than Building
heating, ventilating and air conditioning equipment) as set forth in Paragraph
VII of Exhibit D; costs of building and cleaning supplies and equipment
(including rental); cost of maintenance, cleaning and repairs; cost of snow
plowing or removal, or both, and care of landscaping; payments to independent
contractors under service contracts for cleaning, operating, managing,
maintaining and repairing the Building and Lot (which payments may be to
affiliates of Landlord provided the same are at reasonable rates consistent with
similar contracts with unaffiliated third parties); the Building's pro rata
share (as hereinafter defined) of the cost of operating, maintaining and
repairing the Common Areas of the Park (such as, but not limited to, snow
plowing, sanding, landscaping, common area and street lighting, security,
management and sewer treatment plant maintenance); and all other reasonable and
necessary expenses paid in connection with the operation, cleaning, maintenance,
and repair of the Building and Lot, or either, and properly chargeable against
income, it being agreed that if Landlord installs a new or replacement capital
item for the purpose of reducing Landlord's Operating Costs, the costs thereof
as reasonably amortized by Landlord over the useful life in years of the capital
item so installed in accordance with generally accepted accounting principles
("GAAP"), consistently applied, with legal interest on the unamortized amounts,
shall be included in Landlord's Operating Costs. Landlord agrees that all of
such services to be included in Landlord's Operating Costs shall be obtained by
Landlord at commercially reasonable, competitive market rates consistent with
the operation and management of comparable "Class A" office buildings in the
suburban Boston area.

         Notwithstanding anything to the contrary contained herein, in no event
shall Landlord's Operating Costs include (nor shall Tenant have any obligation
to pay any Operating Cost Escalation on account of) the following:

         (a)      Costs, expenses and fees relating to solicitation of,
                  advertising for and entering into leases and other occupancy
                  arrangements for space in the Park, including but not limited
                  to legal fees, space planners' fees, real estate brokers'
                  leasing commissions and advertising expenses.

         (b)      Costs of defending any lawsuits with any mortgagee , costs of
                  selling, syndicating, financing, mortgaging or hypothecating
                  any of Landlord's interest in the Park (or any part thereof),
                  costs of any disputes between Landlord and its employees,
                  disputes of Landlord with building management, or outside fees
                  paid in connection with disputes with other tenants or
                  adjacent property owners.

         (c)      Costs of correcting defects in the Building or the Building
                  equipment or replacing defective equipment at any time during
                  the three (3) year period described in Section 3.7, subject to
                  the provisions of said Section 3.7, and thereafter solely to
                  the extent such costs relate to items covered by warranties of
                  manufacturers,

                                       19
<PAGE>   24
                  suppliers or contractors or are otherwise borne by parties
                  other than Landlord and for which Landlord receives
                  reimbursement.

         (d)      Costs of installations or improvements of any type paid by or
                  constructed for specific tenants or other occupants.

         (e)      Interest, points, other finance charges and principal payments
                  on mortgages, and other costs of indebtedness, if any.

         (f)      All amounts which are specifically charged to or otherwise
                  paid by any other tenant or other occupant of the Building or
                  the Park, or for items or services which Landlord provides
                  selectively to one or more tenants (other than Tenant) without
                  reimbursement.

         (g)      Any bad debt loss, rent loss or reserves for bad debts or rent
                  loss.

         (h)      The salary and indirect compensation (including, without
                  limitation, all fringe benefits, workmen's compensation,
                  insurance premiums and payroll taxes) of any employee above
                  the trade of building manager, and the wages and indirect
                  compensation of any employee to the extent such employee
                  devotes his or her time to property other than the Building.

         (i)      Amounts, if any, paid as ground rental by Landlord.

         (j)      Expenses related to landlord-tenant disputes.

         (k)      Management fees in excess of five percent (5%) of gross
                  collected rents.

         (l)      Costs related to hazardous material clean-up, remediation and
                  other expenses (unless due to Tenant's actions), Landlord and
                  Tenant hereby agreeing that in no way shall this exclusion
                  limit or impair Tenant's obligations set forth in Section
                  6.1.17 hereof.

         (m)      Costs of capital improvements, except for such capital
                  improvements specifically provided for in this Section 4.2.

         Notwithstanding any language to the contrary contained herein,
Landlord's Operating Costs shall be reduced by reimbursements, credits,
discounts, reductions or other allowances received or receivable by Landlord for
items of cost included in Landlord's Operating Costs (except for reimbursements
to Landlord by tenants under the additional rent provisions of their respective
leases), including any tax refunds realized as a result of any abatement
proceeding or otherwise.

         Tenant shall be responsible to pay its share of Operating Cost
Escalation (as defined below) for the Building based upon the proportion that
the Rentable Floor Area of Tenant's

                                       20
<PAGE>   25
Space bears to the Total Rentable Floor Area of the Building. Landlord and
Tenant hereby acknowledge and agree that the Building's pro rata share of
Park-related costs shall be allocated by Landlord in a commercially reasonable
manner based upon the following: upon the ratio of the square footage of the
Premises to the aggregate square footage of all completed buildings in the Park,
as such buildings are completed from time to time, and, with respect to sewer
treatment plant expenses, connected for service from time to time to the sewer
treatment plant, and upon factors such as usage of a particular tenant in the
Park and/or such other pertinent factors as reasonably determined by Landlord.

         "Operating Cost Escalation" shall be equal to the difference, if any,
between:

         (a)      the product of Landlord's Operating Costs per rentable square
                  foot as indicated in Landlord's Statement times the Rentable
                  Floor Area of Tenant's Space; and

         (b)      the product of the Annual Estimated Operating Costs per
                  rentable square foot times the Rentable Floor Area of Tenant's
                  Space.

         If, with respect to any Fiscal Year or fraction thereof during the
Term, Tenant is obligated to pay Operating Cost Escalation, then Tenant shall
pay, as additional rent, on the first day of each month of each ensuing Fiscal
Year thereafter, until Landlord's Statement for an ensuing Fiscal Year reflects
that Tenant is not obligated to pay Operating Cost Escalation, Estimated Monthly
Escalation Payments equal to 1/12th of the annualized Operating Cost Escalation
for the immediately preceding Fiscal Year, Estimated Monthly Escalation Payments
for each ensuing Fiscal Year shall be made retroactively from the first day of
such Fiscal Year and on account of the payment to be made pursuant to the first
sentence of this Section 4.2 for such Fiscal Year, with an appropriate
additional payment or refund to be made at the time such payment is due.

         The term "Fiscal Year" as used in this Article shall mean the period of
twelve (12) consecutive months commencing on January 1 and ending on
December 31.

         The term "real estate taxes" as used above shall mean all ad valorem
real estate taxes assessed by any governmental authority on the Lot, the
Building and improvements, or both, and the Common Areas of the Park, subject to
the following: There shall be excluded from such taxes (i) any governmental or
business park "special assessments" (i.e. roads and sewers) not considered to be
"property" taxes hereunder, and (ii) all income taxes, excess profits taxes,
excise taxes, franchise taxes, estate, succession, inheritance and transfer
taxes, provided, however, that if at any time during the Term the present system
of ad valorem taxation of real property shall be changed so that in lieu of the
whole or any part of the ad valorem tax on real property, there shall be
assessed on Landlord a capital levy or other tax on the gross rents received
with respect to the Lot, Building and improvements, or both, and the Common
Areas of the Park, a federal, state, county, municipal, or other local income,
franchise, excise or similar tax, assessment, levy or charge (distinct from any
now in effect) measured by or based, in whole or primarily, upon any such gross
rents, then any and all of such taxes, assessments, levies or charges, to the
extent so measured or based, shall be deemed to be included within the term
"real estate taxes".

                                       21
<PAGE>   26
         If the total of the monthly payments paid by Tenant with respect to any
Fiscal Year exceeds the actual Operating Cost Escalation for such Fiscal Year,
then, at Landlord's option, such excess shall be either (i) credited against
payments on account of Operating Cost Escalation next due hereunder, or (ii)
refunded by Landlord to Tenant.

         The amount of any refund of real estate taxes shall be credited against
real estate taxes for the Fiscal Year in which such refund is received;
provided, however, in the event that Landlord receives a refund on account of
real estate taxes after the expiration of the Term, which refund relates to a
Fiscal Year during the Term, the amount of such refund fairly allocable to
Tenant shall be refunded to Tenant by Landlord. All references to real estate
taxes "for" a particular Fiscal Year shall be deemed to refer to real estate
taxes due and payable during such Fiscal Year without regard to when such
impositions are assessed or levied.

         All records that the Landlord is required to maintain hereunder shall
be maintained by the Landlord for a period of two (2) years following the
expiration of the Fiscal Year to which such records relate. Tenant shall have
the right, through its representatives, but not an obligation, to examine, copy
and audit such records at reasonable times, but no more than once per Fiscal
Year, upon not less than thirty (30) days prior written notice. Such records
shall be maintained at Landlord's Address set forth in Section 1.1, or such
other place within the Commonwealth of Massachusetts as Landlord shall designate
from time to time for the keeping of such records. The costs of such audits
shall be borne by Tenant; provided, however, that if such audit establishes that
the actual Operating Cost Escalation for the Fiscal Year in question is less
than the Landlord's final determination of the Operating Cost Escalation as set
forth in the Landlord's Statement submitted to Tenant by at least ten (10%)
percent, then Landlord shall pay the reasonable cost of such audit. If, as a
result of such audit, it is determined that Tenant must pay additional amounts
to Landlord on account of the Operating Cost Escalation, or that Tenant has
overpaid Landlord on account of the Operating Cost Escalation, then the
undercharged or overpaid party shall reimburse the other party for the payment
due, together with interest thereon from the date of Landlord's Statement at the
interest rate set forth in Section 4.3 hereof. In no event shall the provisions
of this paragraph require Tenant to complete any such audit.

         Notwithstanding anything contained to the contrary in this Lease, the
initial responsibility for the payment of all real estate taxes with respect to
the Building and the Park shall be upon the Landlord and the Landlord agrees to
pay the same as required by law. Landlord shall provide Tenant with a
computation of Tenant's pro rata share thereof, and upon Tenant's request,
copies of all tax bills.

         Landlord shall have the right from time to time to change the periods
of accounting under this Section 4.2 to any annual period other than the Fiscal
Year and upon any such change all items referred to in this Section shall be
appropriately apportioned. In all Landlord's Statements, rendered under this
Section, amounts for periods partially within and partially without the
accounting periods shall be appropriately apportioned, and any items which are
not determinable at the time of a Landlord's Statement shall be included therein
on the basis of Landlord's estimate, and with respect thereto Landlord shall
render promptly after determination a

                                       22
<PAGE>   27
supplemental Landlord's Statement, and appropriate adjustment shall be made
according thereto. All Landlord's Statements shall be prepared in accordance
with GAAP.

         Notwithstanding any other provision of this Section 4.2, if the Term
expires or is terminated as of a date other than the last day of a Fiscal Year
at the end of the Term, Tenant's last payment to Landlord under this Section 4.2
shall be made on the basis of Landlord's best estimate of the items otherwise
includable in Landlord's Statement and shall be made on or before the later of
(a) ten (10) days after Landlord delivers such estimate to Tenant, or (b) the
last day of the Term, with an appropriate payment or refund to be made upon
submission of Landlord's Statement. Without limitation, the obligation of Tenant
to pay the Operating Cost Escalation with respect to any Fiscal Year during the
Term (or portion thereof) shall survive the expiration or earlier termination of
the Term.

4.3      PAYMENTS

         All payments of Fixed Rent and additional rent shall be made to
Managing Agent, or to such other person as Landlord may from time to time
designate in writing. If any installment of rent, Fixed Rent or additional, or
on account of leasehold improvements is paid more than five (5) business days
after the due date thereof, at Landlord's election, it shall bear interest at
the rate of eighteen percent (18%) per annum (or, if lower, the maximum rate
permitted by law).

                                    ARTICLE V
                              LANDLORD'S COVENANTS

5.1      LANDLORD'S COVENANTS DURING THE TERM

         Landlord covenants during the Term:

         5.1.1    Building Services - To furnish, through Landlord's employees
                  or independent contractors, the services listed in Exhibit D;

         5.1.2    Additional Building Services - To furnish, through Landlord's
                  employees or independent contractors, reasonable additional
                  Building operation services upon reasonable advance request of
                  Tenant at reasonable and competitive rates from time to time
                  established by Landlord to be paid by Tenant;

         5.1.3    Repairs - Except as otherwise provided in Article VII, except
                  as resulting from Tenant's negligence or misuse, except as
                  resulting from settling or sagging within standard engineering
                  tolerance (provided that the settling or sagging does not
                  affect the surface or structural integrity of the Building or
                  in any way materially affect the ordinary and customary use of
                  the Premises, or any part thereof by Tenant), or except for
                  damage or deterioration resulting from reasonable wear and
                  damage, Landlord shall keep in good order, condition and
                  repair, the roof of the Building, all gutters and downspouts,
                  foundations, exterior (including exterior painting and finish)
                  and structural portions of the Building, all Building systems

                                       23
<PAGE>   28
                  serving the Building, and all plumbing and utility lines
                  serving the Premises, whether located within or outside of the
                  Premises. The Landlord's obligations shall include, without
                  limitation, the obligation to make all necessary repairs,
                  replacements or alterations to the roof, the exterior walls,
                  the foundation, the floor slabs and all other structural
                  elements of the Building, to maintain the Building Parking
                  Area and to maintain in good order and condition the Lot and
                  the other lots, buildings and improvements located within the
                  Park, including but not limited to the Common Areas of the
                  Park (e.g. parking areas, passageways, driveways, sidewalks,
                  roadways, and sewer treatment plant). Landlord shall maintain
                  in good operating condition throughout the Term, reasonable
                  wear and tear excepted, repair and replace the HVAC equipment
                  in the Building, in accordance with the requirements of the
                  Landlord's Plans (expressly excluding the HVAC system(s), if
                  any, not specifically described in Landlord's Plans, (i)
                  unless otherwise mutually agreed upon by Landlord and Tenant
                  in writing or (ii) unless the parties determine that it is
                  difficult or in practical to maintain the HVAC system(s)
                  separately, the parties hereby agreeing in such event that
                  Landlord shall maintain all HVAC systems and shall charge
                  Tenant the incremental cost thereof pursuant to Section 4.2
                  hereof), and shall assign (to the extent assignable) all
                  warranties and guarantees with respect thereto to Tenant.
                  Tenant may elect, at its cost and expense and upon the prior
                  consent of Landlord (which such consent shall not be
                  unreasonably withheld or delayed), to bring actions to enforce
                  remedies under said warranties or guarantees in the name of
                  the Landlord or jointly with Landlord, at no expense to
                  Landlord;

         5.1.4    Quiet Enjoyment - That Landlord has the right to make this
                  Lease and that Tenant, on paying the rent and performing its
                  obligations hereunder, shall peacefully and quietly have, hold
                  and enjoy the Premises throughout the Term without any manner
                  of hindrance or molestation from Landlord or anyone claiming
                  under Landlord, subject, however, to all the terms and
                  provisions hereof;

         5.1.5    Intentionally Deleted.

         5.1.6    Landlord's Insurance - Beginning with the commencement of
                  Landlord's Work and thereafter throughout the Term, Landlord
                  shall purchase and keep in force, broad-form commercial
                  general liability insurance, or the equivalent then-customary
                  form providing comparable coverages, written out on an
                  occurrence basis containing provisions adequate to protect the
                  Landlord from and against claims for bodily injury, including
                  death and personal injury and claims for property damage
                  occurring within the Park and/or the Building, such insurance
                  having body injury and property damage combined limits of not
                  less than five million dollars ($5,000,000) per occurrence. In
                  addition, Landlord shall procure and continue in force during
                  the Term, as the same may be extended hereunder, fire and
                  extended coverage insurance, including vandalism, sprinkler
                  leakage and malicious mischief, upon the Building on a full
                  replacement cost basis, agreed cost value endorsement with
                  agreed values for the Building and other tenant

                                       24
<PAGE>   29
                  improvements and alterations, as determined annually by the
                  Landlord's insurer. Landlord shall also procure and continue
                  in force during the Term, as the same may be extended
                  hereunder, rental interruption insurance for twelve (12)
                  months or the maximum amounts permitted. Copies of
                  certificates of insurance evidencing the foregoing shall be
                  furnished to Tenant, upon Tenant's reasonable request. All
                  insurance required of Landlord pursuant to this Section shall
                  be effected under policies issued by insurers or recognized
                  responsibility (which are rated A or A+ by Best's Rating
                  Service or a comparable rating by an equivalent service). The
                  coverages required by this Section 5.1.6 may be provided by a
                  single "package policy";

         5.1.7    Landlord's Indemnity - Landlord covenants and agrees to
                  defend, with counsel reasonably acceptable to Tenant, save
                  harmless and indemnify Tenant from any liability for injury,
                  loss, accident or damage to any person or property on the
                  Premises or the Park, and from any claims, actions,
                  proceedings and reasonable expenses and costs in connection
                  therewith (including, without implied limitation, reasonable
                  counsel fees), arising directly from the negligent acts and/or
                  willful misconduct of Landlord not caused directly by the
                  negligent acts or willful misconduct of Tenant. In no event
                  shall Landlord be obligated to indemnify Tenant for any
                  willful or negligent act or omission of Tenant or of any of
                  Tenant's employees, agents, contractors or licensees;

         5.1.8    Hazardous Materials - Landlord represents and warrants that,
                  to the best of Landlord's knowledge as of the date of this
                  Lease and as of the date of Substantial Completion (i) there
                  does not exist (and will not exist as of the date of
                  Substantial Completion) any leak, spill, release, discharge,
                  emissions or disposal of Hazardous Materials on the Lot
                  (including the Building to be located thereon), and (ii) the
                  Premises do not (and will not as of the date of Substantial
                  Completion) contain any Hazardous Materials, except as may be
                  contained in customary cleaning supplies or in such other
                  supplies (e.g. paint) that are necessary for Landlord to
                  perform its obligations hereunder. In the event that any such
                  leak, spill, release, discharge, emission or disposal of
                  Hazardous Materials shall occur on the Lot or (apart from DE
                  MINIMIS amounts of such materials used for cleaning and
                  maintenance purposes or in connection with the operation of
                  loading docks) the Park not caused by Tenant or its officers,
                  employees, agents, contractors or licensees, Landlord shall
                  take any and all actions necessary to bring the Premises, the
                  Park and/or the Building (excluding all portions thereof
                  leased or leasable to tenants) into compliance with applicable
                  law and other governmental requirements relating thereto.

                  Landlord agrees to notify Tenant immediately upon discovery of
                  any Hazardous Materials on the Premises or in the Park and to
                  indemnify, defend and hold harmless Tenant and its officers,
                  employees and agents from and against any claims, judgments,
                  damages, penalties, fines, costs, liabilities or loss
                  (including

                                       25
<PAGE>   30
                  without limitation reasonable attorneys' fees) which arise
                  during or after the date hereof from or in connection with the
                  presence or suspected presence of Hazardous Materials on the
                  Premises or in the Park caused directly by the negligent acts
                  or willful misconduct of Landlord. Notwithstanding any
                  language to the contrary set forth in this Lease, in no event
                  shall Landlord be obligated to indemnify Tenant for any
                  Hazardous Materials which arise, as a result of the negligent
                  acts or willful misconduct of Tenant, its officers, employees,
                  agents, contractors or licensees. The covenants and
                  indemnifications set forth in this Section 5.1.8 shall survive
                  the expiration or earlier termination of this Lease; and

         5.1.9    Tenant's Costs - In case Tenant shall, without any fault on
                  its part, be made party to any litigation commenced by or
                  against Landlord or by or against any parties in possession of
                  the Premises or any part thereof claiming under Landlord,
                  Landlord agrees to reimburse Tenant for all reasonable costs,
                  including without implied limitation, reasonable counsel fees,
                  incurred by or imposed upon Tenant in connection with such
                  litigation and to pay all such reasonable costs and fees
                  incurred in connection with the successful enforcement by
                  Tenant of any obligations of Landlord under this Lease.

         Except as specifically provided to the contrary in Section 4.2,
Landlord shall charge Tenant under the provisions of Section 4.2 for the costs
incurred by Landlord in connection with the services and/or repairs set forth in
Sections 5.1.1, 5.1.2, 5.1.3 and 5.1.6 above; provided, however, Landlord shall
be responsible to pay the following, at its sole cost and expense: (i) repairs
or replacements which are necessary to maintain the structural integrity of the
Building and the roof during the Term of this Lease (expressly including any
renewal terms hereunder), and (ii) maintenance and repairs (and replacements, if
necessary) during the initial one (1) year period (or three (3) year period as
to latent defects) described in Section 3.7 or otherwise covered by Landlord's
or manufacturers warranties described in Section 3.7 above.

                                       26
<PAGE>   31
5.2      INTERRUPTIONS

         Except as otherwise set forth below in this Section 5.2, Landlord shall
not be liable to Tenant for any compensation or reduction of rent by reason of
inconvenience or annoyance or for loss of business arising from power losses or
shortages or from the necessity of Landlord's entering the Premises for any of
the purposes in this Lease authorized, or for repairing the Premises or any
portion of the Building or Lot. In case, notwithstanding Landlord's diligent
efforts in connection therewith (which such efforts shall never obligate
Landlord to pay for overtime and/or premium time work, or to pay a premium for
expedited delivery, except as such additional costs are so authorized and paid
for by Tenant), Landlord is prevented or delayed from making any repairs,
alterations or improvements, or furnishing any service or performing any other
covenant or duty to be performed on Landlord's part, by reason of any cause
reasonably beyond Landlord's control (expressly excluding Landlord's financial
inability), Landlord shall not be liable to Tenant therefore, nor, except as
expressly otherwise provided in Article III or Article VII, shall Tenant be
entitled to any abatement or reduction of rent by reason thereof, nor shall the
same give rise to a claim in Tenant's favor that such failure constitutes,
actual or constructive, total or partial, eviction from the Premises.

         Landlord reserves the right to stop any service or utility system when
necessary by reason of accident or emergency or until necessary repairs have
been completed. Except in case of emergency repairs, Landlord will give Tenant
reasonable advance notice of any contemplated stoppage and will use reasonable
efforts to avoid unnecessary inconvenience to Tenant by reason thereof.

         Notwithstanding any language to the contrary, if, due solely to any act
or omission on the part of Landlord, electricity, heat, air conditioning, water
or any other service or utility that Tenant is entitled to receive under this
Lease is interrupted, and such interruption renders the Premises untenantable,
or any portion thereof is reasonably inaccessible by Tenant, or makes it
impracticable for Tenant to conduct its business in the Premises, then if such
interruption or cessation shall continue for a period of thirty (30) consecutive
days after notice thereof from Tenant to Landlord that the Premises are
untenantable, or reasonably inaccessible, or Tenant cannot conduct its business
as a result thereof, then the Fixed Rent and additional rent shall be
proportionately abated for each successive day such interruption or cessation
continues based upon that certain portion of the Premises that are affected by
such interruption (other than for reasons of casualty or eminent domain where
the provisions of Article VII shall govern). In addition, in the event that any
such interruption or cessation shall continue for more than ninety (90)
successive days, after notice thereof from Tenant to Landlord that the Premises
are untenantable, or reasonably inaccessible, or Tenant cannot conduct its
business as a result thereof, then Tenant shall have the right to cancel this
Lease by giving written notice to Landlord and its mortgagee(s) (of which Tenant
has received written notice) of such cancellation, provided that at least ten
(10) days prior written notice to Landlord and thirty (30) days prior written
notice to Landlord's mortgagee has been given (which such notice may be given
prior to or after the expiration of said ninety (90) day period), unless within
such ten (10) day period Landlord repairs or restores such interruption as
herein required, in which event such notice of cancellation from Tenant shall be
rendered

                                       27
<PAGE>   32
null and void and of no further force or effect. For purposes of this Section,
Landlord and Tenant hereby acknowledge and agree that if the Premises (or
portion thereof) is rendered inaccessible by elevator, but accessible by
stairway(s), then the Premises (or such portion) will not be deemed "reasonably
inaccessible" for the purposes hereof.

         Notwithstanding anything to the contrary contained in this Section 5.2,
in no event shall Tenant be entitled to any such abatement or reduction of rent
or to any such right of termination if such interruption resulting in the
Premises being untenantable or unfit for Tenant's business operations therein is
due to an event of default by Tenant as set forth in Section 9.1 hereof or is
not due to any act or omission on the part of Landlord. Except as set forth in
this Section 5.2 or in Article VII, the foregoing rights shall be Tenant's sole
remedy at law or in equity for any interruptions described in this Section 5.2.

                                   ARTICLE VI
                               TENANT'S COVENANTS

6.1      TENANT'S COVENANTS DURING THE TERM

         Tenant covenants during the Term:

         6.1.1    Tenant's Payments - To pay when due (a) all Fixed Rent and
                  additional rent, (b) all taxes which may be imposed on
                  Tenant's personal property in the Premises (including, without
                  limitation, Tenant's fixtures and equipment) (c) directly to
                  the utility provider (if not payable to Landlord), subject
                  however, to Tenant's right to contest and seek abatement
                  thereof, all charges by public utility for telephone and other
                  utility services (including service inspections therefor and
                  the charges as may be imposed pursuant to Exhibit D hereof
                  including all electric and gas consumed on the Premises)
                  rendered to the Premises not otherwise required hereunder to
                  be furnished by Landlord without charge and not consumed in
                  connection with any services required to be furnished by
                  Landlord without charge, and (d) as additional rent, all
                  reasonable charges of Landlord for services rendered pursuant
                  to Section 5.1.1, 5.1.2, 5.1.3, and 5.1.6 hereof, except as
                  set forth in the last paragraph of Section 5.1.

         6.1.2    Repairs and Yielding Up - Except as otherwise provided in
                  Article VII and Section 5.1.3, to keep the interior,
                  non-structural and non-building system elements of the
                  Premises in good order, repair and condition, reasonable wear
                  and damage or destruction by casualty or eminent domain
                  excepted, and at the expiration or termination of this Lease
                  peaceably to yield up the Premises and all changes and
                  additions therein in such order, repair and condition, first
                  removing all goods and effects of Tenant and any items, the
                  removal of which is required by agreement or specified therein
                  to be removed at Tenant's election and which Tenant elects to
                  remove, Landlord and Tenant hereby acknowledging and agreeing,
                  however, that the initial improvements constructed by Landlord
                  pursuant to Article III and described in Landlord's Plans and
                  Tenant's Plans

                                       27
<PAGE>   33
                  referenced therein (including without limitation any
                  cafeteria(s) and laboratories) shall not be required to be
                  removed by Tenant upon expiration of the Term, as hereinbefore
                  provided in Section 3.1, and repairing all damage caused by
                  such removal and leaving them clean and neat; any property not
                  so removed shall be deemed abandoned and may be removed and
                  disposed of by Landlord, in such manner as Landlord shall
                  determine, and Tenant shall pay Landlord the entire reasonable
                  cost and expense incurred by it by effecting such removal and
                  disposition;

         6.1.3    Occupancy and Use - To use and occupy the Premises only for
                  the Permitted Uses; and not to injure or deface the Premises,
                  Building or Lot; and not to permit in the Premises any auction
                  sale, nuisance, or the emission from the Premises of any
                  objectionable noise or odor, nor to permit any use thereof
                  which is improper, offensive, contrary to law or ordinances,
                  or liable to invalidate or increase the premiums for any
                  insurance on the Building or its contents or liable to render
                  necessary any alteration or addition to the Building, unless
                  Tenant agrees to pay such increased premiums and/or costs, and
                  such use (if other than Permitted Uses) is approved by
                  Landlord in advance;

         6.1.4    Rules and Regulations - To comply with the Rules and
                  Regulations set forth in Exhibit E and all other reasonable
                  Rules and Regulations hereafter made by Landlord, of which
                  Tenant has been given notice, for the care and use of the
                  Building, Lot and Common Areas of the Park (and their
                  facilities and approaches as further described in the Park
                  Covenants attached hereto as Exhibit I), it being understood
                  that Landlord shall not be liable to Tenant for the failure of
                  other tenants of the Building or Park to conform to such Rules
                  and Regulations; provided that (i) such Rules and Regulations
                  are enforced in a non-discriminatory fashion, (ii) such Rules
                  and Regulations do not materially interfere with or otherwise
                  diminish Tenant's use of the Premises and the Building Parking
                  Area or Tenant's rights under this Lease, (iii) result in no
                  additional cost or expense to Tenant, and (iv) do not impose
                  any additional obligation on Tenant.

         6.1.5    Compliance with Laws and Safety Appliances - To keep, from and
                  after the initial installation thereof by Landlord, subject to
                  the provisions of Section 10.18 (c), the Premises equipped
                  with all safety appliances required by law or ordinance or any
                  other regulation of any and public authority because of any
                  particular manner of use made by Tenant and to procure and
                  comply with all licenses and permits so required because of
                  such use, it being understood that the foregoing provisions
                  shall not be construed to broaden in any way Tenant's
                  Permitted Uses. Tenant shall have the right, upon giving
                  notice to the Landlord, to contest any obligation imposed upon
                  it pursuant to the provisions of this Section 6.1.5, and
                  provided the enforcement of such requirement or law is stayed
                  during such contest and such contest will not subject the
                  Landlord to penalty or jeopardize the title to the Premises or
                  otherwise affect the Premises in any adverse way. Landlord
                  shall cooperate with Tenant in such contest and shall execute
                  any documents

                                       29
<PAGE>   34
                  reasonably required in the furtherance of such purpose.
                  Notwithstanding the foregoing or any other provision of this
                  Lease, however, Tenant shall not be responsible for compliance
                  with any such laws, regulations, or the like requiring (i)
                  structural repairs or modifications or (ii) repairs or
                  modifications to the utility or building service equipment
                  located outside of and not exclusively serving the Premises or
                  (iii) installation of new building service equipment, such as
                  fire detection or suppression equipment, unless such repairs,
                  modifications, or installations shall (a) be due to Tenant's
                  Construction Work, alterations, or repairs in the Premises or
                  Tenant's particular manner of use of the Premises (as opposed
                  to commercial office operations, generally), or (b) be due to
                  the negligence or willful misconduct of Tenant's or any agent,
                  employee, or contractor of Tenant.

         6.1.6    Assignment and Subletting -Tenant shall have the right,
                  subject to the requirement of obtaining Landlord's prior
                  written consent, such consent not to be unreasonably withheld
                  or delayed by Landlord, to assign this Lease or sublet the
                  whole or any portion of the Premises, which assignment or
                  sublease shall be only for the Permitted Uses, it being
                  understood that Tenant shall, as additional rent, reimburse
                  Landlord promptly for reasonable legal and other expenses
                  incurred by Landlord in connection with any request by Tenant
                  for consent to assignment or subletting. No assignment or
                  subletting shall affect the continuing primary liability of
                  Tenant (which, following assignment, shall be joint and
                  several with the assignee). Such consent by Landlord to any of
                  the foregoing in a specific instance (i) shall be reasonable,
                  subject to the provisions hereinafter provided, and (ii) shall
                  be subject to the prior written approval of Landlord's
                  mortgagee(s). Landlord's consent shall not be treated as
                  having been withheld unreasonably if, in connection with any
                  such proposed assignment or subletting: (i) the terms of the
                  proposed assignment or subletting do not prohibit further
                  assignments of the Lease or subletting of the Premises without
                  the written consent of Landlord, the granting of which consent
                  shall be subject to the terms and conditions hereof, and in
                  any event shall not be unreasonably withheld or delayed;
                  and/or (ii) in connection with an assignment of this Lease,
                  the assignee does not agree directly with Landlord, by written
                  instrument in form reasonably satisfactory to Landlord, to be
                  bound by all the obligations of Tenant hereunder including,
                  without limitation, the covenant against further assignment
                  and subletting without the written consent of Landlord; and/or
                  (iii) the proposed assignment or subletting violates any
                  exclusive use restrictions or exclusions of the Building or
                  Park as set forth in Exhibit Q. Tenant hereby acknowledges and
                  agrees that the foregoing is not intended to be an exclusive
                  list of the reasons for which Landlord may reasonably withhold
                  consent to a proposed request by Tenant for consent to
                  assignment or subletting. No consent to any of the foregoing
                  in a specific instance shall operate as waiver in any
                  subsequent instance.

                  If an assignment or subletting is proposed to be made and
                  Landlord's consent is required as hereinabove provided, Tenant
                  shall give Landlord prior notice of such proposal, which such
                  notice shall include such information as Landlord may

                                       30
<PAGE>   35
                  reasonably request relative to facts which would bear upon the
                  factors entering into the determination whether Landlord's
                  approval is to be granted, and it is understood that Landlord
                  shall use diligent efforts within a period of thirty (30) days
                  after the submission of such information by Tenant to make its
                  determination whether Landlord's approval is to be granted
                  hereunder. If Tenant requests Landlord's consent to assign
                  this Lease or sublet more than sixty percent (60%) of the
                  Premises, Landlord shall have the option, exercisable by
                  written notice to Tenant given within thirty (30) days after
                  receipt of such request, to recapture the portion of the
                  Premises proposed to be assigned or sublet as of a date
                  specified in such notice which shall be not less than
                  forty-five (45), or more than sixty (60) days after the date
                  of such notice, in such event the recaptured area of the
                  Premises shall be removed from the Premises and Tenant shall
                  have no further liabilities or obligations with respect
                  thereto, including obligations to pay Fixed Rent, additional
                  rent or other charges with respect thereto; and any rental
                  received by Tenant from sub-tenant must be remitted to
                  Landlord; provided, however, upon Tenant's receipt of any such
                  written notice from Landlord exercising its right of recapture
                  hereunder, Tenant shall have the option, exercisable by
                  written notice to Landlord given within ten (10) days after
                  receipt of such Landlord's notice, to withdraw its request to
                  assign or sublet all or a portion of the Premises, whereupon
                  Landlord's notice to Tenant exercising its right of recapture
                  hereunder shall become null and void and of no force or effect
                  as to Tenant's particular request for Landlord's consent
                  hereunder.

                  Notwithstanding any provision contained in this Lease, no
                  consent of Landlord shall be required for the assignment of
                  this Lease or the subletting of any portion (or the whole) of
                  the Premises for the Permitted Uses, (i) to a subsidiary of
                  Tenant, (ii) to a corporation or other entity into or with
                  which Tenant has merged or consolidated or to which
                  substantially all of Tenant's stock or assets are transferred,
                  (iii) to any corporation or other entity which controls, is
                  controlled by, or is under common control with Tenant, or (iv)
                  to any corporation or other entity with which Tenant is
                  otherwise affiliated (collectively, the "Permitted
                  Transferees"); provided that, in any of such events, Tenant
                  shall remain directly and primarily liable and any such
                  sublessee or assignee agrees directly with Landlord by written
                  instrument reasonably satisfactory to Landlord and such
                  assignee or sublessee to be bound by all of the obligations of
                  Tenant. In the event of any such assignment or subletting for
                  which no consent by Landlord is required hereunder, Tenant
                  shall not be obligated to share Rent Differential as
                  hereinafter set forth, nor shall the recapture rights of
                  Landlord set forth in the preceding paragraph be applicable.

                  If this Lease shall be assigned, or if the Premises or any
                  part hereof shall be sublet or occupied by any person other
                  than Tenant, Landlord may, at any time and from time to time,
                  collect rent from the assignee, subtenant or occupant and
                  apply the net amount collected to the annual Fixed Rent,
                  additional rent and all other charges herein reserved, but no
                  such assignment, subletting, occupancy or

                                       31
<PAGE>   36
                  collection shall be deemed a waiver of the provisions of this
                  Section 6.1.6, or acceptance of the assignee, subtenant or
                  occupant as tenant, or a release of Tenant from the further
                  performance of the terms, covenants and conditions of this
                  Lease on the part of Tenant to be performed. Further, no
                  liability hereunder of Tenant shall be discharged, reduced,
                  released or impaired in any respect by any waiver, indulgence
                  or extension of time which Landlord may grant to the then
                  owner of Tenant's interest in this Lease, whether or not
                  notice thereof has been given or consent from Tenant has been
                  obtained.

                  Landlord shall have the option to require that any portion of
                  rental received by Tenant from subtenant or assignee to which
                  Landlord is entitled pursuant to this Section 6.1.6 be
                  remitted directly to Landlord, provided that such amounts are
                  credited pro tanto against Tenant's rental obligations.

                  If Landlord approves a sublease or assignment, and said
                  sublease or assignment is for a total rental amount which on
                  an annualized basis is greater than the Fixed Rent and
                  additional rent due from Tenant to Landlord under this Lease,
                  Tenant shall pay to Landlord, forthwith upon Tenant's receipt
                  of each installment of such excess rent, during the term of
                  any approved sublease or assignment, as additional rent
                  hereunder, in addition to the Fixed Rent and other payments
                  due under this Lease, an amount equal to fifty percent (50%)
                  of the positive excess between all fixed rent and additional
                  rent received by Tenant under the sublease or assignment and
                  the Fixed Rent and the additional rent due hereunder after
                  Tenant has recouped its reasonable out-of-pocket expenses with
                  respect to such sublease or assignment, including without
                  limitation, reasonable real estate brokerage commissions,
                  reasonable legal fees, reasonable free rent, reasonable
                  marketing costs and the reasonable costs of refurbishment of
                  the Premises for such sublease or assignment (the "Rent
                  Differential"). In the event the sublease is for less than the
                  full Premises hereunder, the above rent adjustment shall be
                  equitably pro rated on a square foot basis. Anything contained
                  in the foregoing provisions of this section to the contrary
                  notwithstanding, neither Tenant nor any other person having
                  interest in the possession, use, occupancy or utilization of
                  the Premises shall enter into any lease, sublease, license,
                  concession or other agreement for use, occupancy or
                  utilization of space in the Premises which provides for rental
                  or other payment for such use, occupancy or utilization based,
                  in whole or primarily on the net income or profits derived by
                  any person from the Premises leased, used, occupied or
                  utilized (other than an amount based on a fixed percentage or
                  percentages of receipts or sales), and any such purported
                  lease, sublease, license, concession or other agreement shall
                  be absolutely void and ineffective as a conveyance of any
                  right or interest in the possession use, occupancy or
                  utilization of any part of the Premises;

         6.1.7    Indemnity - To defend, with counsel reasonably acceptable to
                  Landlord, save harmless, and indemnify Landlord from any
                  liability for injury, loss, accident or damage to any person
                  or property occurring on the Premises, in the Building, or

                                       32
<PAGE>   37
                  elsewhere in the Park, and from any claims, actions,
                  proceedings and expenses and costs in connection therewith or
                  elsewhere in the Park (including, without implied limitation,
                  reasonable counsel fees): (i) arising from the negligent acts
                  or gross misconduct of Tenant or any of Tenant's employees,
                  agents, contractors, licensees or invitees and not caused
                  directly by the negligent acts or gross misconduct of
                  Landlord, or (ii) resulting from the failure of Tenant to
                  perform and discharge its covenants and obligations under this
                  Lease. In no event shall Tenant be obligated to indemnify
                  Landlord for any willful or negligent act or omission of
                  Landlord or any of Landlord's employees, agents, contractors
                  or licensees. The covenants and indemnifications set forth in
                  this Section 6.1.7 shall survive the expiration or earlier
                  termination of this Lease;

         6.1.8    Tenant's Liability Insurance - To maintain public liability
                  insurance in the Premises in amounts which shall, at the
                  beginning of the Term, be at least equal to the limits set
                  forth in Section 1.1 and from time to time during the Term,
                  shall be for such higher limits, if any, as are customarily
                  carried in the area in which the Premises are located on
                  property similar to the Premises and used for similar purposes
                  and, upon written request therefor, to furnish Landlord
                  (and/or its mortgagees) with certificates thereof;

         6.1.9    Tenant's Workmen's Compensation Insurance - To keep all
                  Tenant's employees working in the Premises covered by
                  workmen's compensation insurance in statutory amounts and to
                  furnish Landlord with certificates thereof;

         6.1.10   Landlord's Right of Entry - Upon not less than twenty-four
                  (24) hours advance notice (except in the event of
                  emergencies), at times reasonably acceptable to Landlord and
                  Tenant, to permit Landlord and Landlord's agents entry; to
                  examine the Premises at reasonable times and, if Landlord
                  shall so elect, to make repairs or replacements; to remove, at
                  Tenant's expense, any changes, additions, signs, curtains,
                  blinds, shades, awnings, aerials, flagpoles, or other
                  improvements visible outside the Building not consented to in
                  writing by Landlord (Landlord hereby acknowledging that the
                  initial improvements constructed by Landlord pursuant to
                  Article III shall be permitted and may remain upon expiration
                  of the Term as hereinbefore provided in Sections 3.1 and
                  6.1.2); and to show the Premises to prospective tenants during
                  the twelve (12) months preceding expiration of the Term and to
                  prospective purchasers and mortgagees at all reasonable times;

         6.1.11   Loading - Not to place a load upon the Premises exceeding an
                  average rate of one hundred (100) pounds of live load per
                  square foot of floor area; and not to move any safe, vault or
                  other heavy equipment in, about or out of the Premises except
                  in such a manner and at such times as Landlord shall in each
                  instance approve; Tenant's business machines and mechanical
                  equipment which cause vibration or noise that may be
                  transmitted to the Building structure shall be placed and
                  maintained by Tenant in settings of cork, rubber, spring, or
                  other types of vibration eliminators sufficient to eliminate
                  such vibration or noise;

                                       33
<PAGE>   38
         6.1.12   Landlord's Costs - In case Landlord shall, without any fault
                  on its part, be made party to any litigation commenced by or
                  against Tenant or by any party claiming under Tenant, to pay,
                  as additional rent, all actual third party reasonable costs
                  including, without implied limitation, reasonable counsel fees
                  incurred by or imposed upon Landlord in connection with such
                  litigation, and, as additional rent, also to pay all such
                  reasonable costs and fees incurred by Landlord in connection
                  with the successful enforcement by Landlord of any obligations
                  of Tenant under this Lease;

         6.1.13   Tenant's Property - All the furnishings, fixtures, equipment,
                  effects and property of every kind, nature and description of
                  Tenant and of all persons claiming by, through or under Tenant
                  which, during the continuance of this Lease or any occupancy
                  of the Premises by Tenant or anyone claiming under Tenant, may
                  be on the Premises or on the Lot shall be at the sole risk and
                  hazard of Tenant, except for Landlord's gross negligence or
                  willful act or omission, and if the whole or any part thereof
                  shall be destroyed or damaged by fire, water or otherwise, or
                  by the leakage or bursting of water pipes, steam pipes, or
                  other pipes, by theft, or from any other cause, no part of
                  said loss or damage is to be charged to or to be borne by
                  Landlord, except if caused directly by Landlord's gross
                  negligence or willful misconduct;

         6.1.14   Labor or Materialmen's Liens - To pay promptly when due the
                  entire cost of any work done on the Premises by Tenant, its
                  agents, employees, or independent contractors; not to cause or
                  permit any liens for labor or material performed or furnished
                  in connection therewith to attach to the Premises; and within
                  ten (10) days after Tenant's receipt of notice thereof, to
                  discharge or bond over any such liens which may so attach;

         6.1.15   Changes or Additions - Not to make any material changes or
                  additions to the Premises without Landlord's prior written
                  consent, which such consent shall not be unreasonably withheld
                  or delayed. Notwithstanding the foregoing, Tenant may, from
                  time to time, at its own cost and expense and without the
                  consent of Landlord, make non-structural alterations,
                  additions or improvements to the Premises, so long as they do
                  not affect any of the mechanical, electrical or plumbing
                  systems of the Building (collectively herein called
                  "Alterations") whose cost in any one instance is Twenty-Five
                  Thousand Dollars ($25,000.00) or less, provided that Tenant
                  first notifies Landlord in writing of any such Alterations. If
                  Tenant desires to make any Alterations costing in excess of
                  Twenty-Five Thousand Dollars ($25,000.00) in any one instance
                  or any other alteration, including any structural alteration
                  or alteration affecting any of the mechanical, electrical or
                  plumbing systems of the Building, Tenant must first obtain the
                  consent of Landlord thereto, which consent shall not be
                  unreasonably withheld or delayed. If Landlord reasonably
                  concludes that the Alterations involve any construction,
                  alterations or additions requiring unusual expense to readapt
                  the

                                       34
<PAGE>   39
                  Premises to normal office use on the Term Expiration Date,
                  Landlord shall notify Tenant in writing at the time of
                  approval that such readaptation will be required to be made by
                  Tenant prior to such Term Expiration Date without expense to
                  Landlord.

                  Any and all such alterations, including, Alterations may be
                  done by any contractor chosen by Tenant provided any such
                  contractor is reputable, bondable by reputable bonding
                  companies, carries the kind of insurance and in the amounts
                  set forth herein, and will work in harmony with Landlord's
                  contractors and laborers in the Building;

                  Tenant in making any alterations, including Alterations, shall
                  cause all work to be done in a good and workmanlike manner
                  using materials substantially equal to or better than those
                  used in the construction of the Premises or original Tenant's
                  Work and shall comply with or cause compliance with all laws
                  and with any direction given by any public officer pursuant to
                  law. Tenant shall obtain or cause to be obtained and maintain
                  in effect, as necessary, all building permits, licenses,
                  temporary and permanent certificates of occupancy and other
                  governmental approvals which may be required in connection
                  with the making of the alterations, including the Alterations.
                  Landlord shall cooperate with Tenant in the obtaining thereof
                  and shall execute any documents reasonably required in
                  furtherance of such purpose, provided any such cooperation
                  shall be without expense and/or liability to Landlord.

                  At least annually if such Alterations or any other alterations
                  hereunder have occurred during the past calendar year, Tenant
                  shall furnish to Landlord as-built sepias and, if applicable,
                  operating manuals, or, at Landlord's option and only if
                  Tenant's computer system is compatible with that of
                  Landlord's, computer disk specifications compatible with
                  Landlord's computer system of the work done by Tenant during
                  such past year and copies of all permits issued in connection
                  therewith.

                  Tenant shall have its contractor procure and maintain in
                  effect during the term of such alterations, including
                  Alterations, satisfactory insurance coverages with an
                  insurance company or companies authorized to do business in
                  the Commonwealth of Massachusetts, and shall, upon Landlord's
                  request, furnish Landlord with certificates thereof;

         6.1.16   Holdover - To pay to Landlord two hundred percent (200%) the
                  total of the Fixed and additional rent then applicable for
                  each month or portion thereof Tenant shall retain possession
                  of the Premises or any part thereof after the termination of
                  this Lease, whether by lapse of time or otherwise and, also to
                  pay all damages sustained by Landlord on account thereof;
                  provided, however (i) Tenant shall be responsible to pay to
                  Landlord only one hundred fifty percent (150%), and not two
                  hundred percent (200%) as aforesaid, of the total Fixed Rent
                  and additional

                                       35
<PAGE>   40
                  rent then applicable for the first thirty (30) days Tenant
                  retains possession of the Premises or any part thereof after
                  termination of this Lease, and (ii) during such initial thirty
                  (30) day period only, Landlord hereby acknowledges and agrees
                  that no consequential damages shall be due from Tenant
                  hereunder. The provisions of this subsection shall not operate
                  as a waiver by Landlord of any right of re-entry provided in
                  this Lease;

         6.1.17   Hazardous Materials - Tenant shall not (either with or without
                  negligence) cause or permit the escape, disposal or release of
                  any biologically or chemically active or other hazardous
                  substances or materials onto the Premises or the Lot, except
                  in accordance with the requirements of applicable laws and
                  regulations. Tenant shall not allow the storage or use of such
                  substances or materials in any manner not permitted by law,
                  nor allow to be brought into the Premises any such materials
                  or substances except to use in the ordinary course of Tenant's
                  business. Upon Landlord's written request, Tenant shall
                  furnish to Landlord an inventory of the identity of such
                  substances or materials used in the ordinary course of
                  Tenant's business. Without limitation, hazardous substances
                  and materials shall include those described in the
                  Comprehensive Environmental Response, Compensation and
                  Liability Act of 1980, as amended, 42 U.S.C. Section 9601 et
                  seq., the Resource Conservation and Recovery Act, as amended,
                  42 U.S.C. Section 6901 et seq., the Massachusetts Hazardous
                  Waste Management Act, as amended, M.G.L. c.21C, the
                  Massachusetts Oil and Hazardous Material Release Prevention
                  and Response Act, as amended, M.G.L. c.21E, any applicable
                  local ordinance or bylaw, and the regulations adopted under
                  these acts, as amended (collectively, the "Hazardous Waste
                  Laws"). If any lender or governmental agency shall ever
                  require testing to ascertain whether or not there has been any
                  release of hazardous substances or materials, then the
                  reasonable costs thereof shall be reimbursed by Tenant to
                  Landlord upon demand as additional charges if and only if the
                  following conditions are satisfied; (i) if such requirement
                  applies to the Premises and (ii) if an independent, reputable
                  third party engineer employed by Landlord or persons acting
                  under Landlord conclusively determines that such release had
                  been or is likely to have been solely and exclusively caused
                  by Tenant or persons acting under Tenant. If Tenant receives
                  from any federal, state or local governmental agency any
                  notice of violation or alleged violation of any Hazardous
                  Waste Law, or if Tenant is obligated to give any notice under
                  any Hazardous Waste Law, Tenant agrees to forward to Landlord
                  a copy of any such notice within three (3) days of Tenant's
                  receipt or transmittal thereof. In addition, Tenant shall
                  execute affidavits, representations and the like from time to
                  time at Landlord's request concerning Tenant's best knowledge
                  of belief regarding the presence of hazardous substances or
                  materials on the Premises. In all events, Tenant shall
                  indemnify Landlord in the manner provided in Section 6.1.7 of
                  this Lease from any release of hazardous substances or
                  materials on the Premises or elsewhere in the Park to the
                  extent caused by Tenant or persons acting under Tenant.
                  Landlord retains the right to inspect the Premises at all
                  reasonable times, upon reasonable notice to

                                       36
<PAGE>   41

                  Tenant, to ensure compliance with this paragraph. The within
                  covenants shall survive the expiration or earlier termination
                  of the Lease Term;

         6.1.18   Signs - Tenant shall not, without prior written consent of
                  Landlord (which such consent shall not be unreasonably
                  withheld or denied but may be withheld in Landlord's sole
                  discretion if Tenant is not then leasing (including
                  subleasing) one hundred percent (100%) of the initial
                  Building, expressly excluding any expansion hereunder), (a)
                  place any exterior signs visible outside the Building, on the
                  Lot or the Premises or anywhere on the exterior of the
                  Building, or (b) place any curtains, blinds (other than
                  standard vertical blinds), shades, awnings, or flagpoles, or
                  the like, in the Premises or anywhere on or in the Building
                  visible from outside the Premises, except as otherwise
                  expressly set forth below in this Section 6.1.18 or elsewhere
                  in this Lease. Tenant shall pay the expenses involved in the
                  erection of any sign and of obtaining all necessary permits
                  and approvals therefor. Except as otherwise provided below
                  with respect to the initial Building signage, Tenant warrants
                  that it shall obtain (and furnish copies thereof to Landlord)
                  all necessary permits and approvals in compliance with local
                  codes and ordinances prior to erecting any such sign(s).
                  Tenant shall remove any of such sign(s) erected by Tenant or
                  on behalf of Tenant upon the termination of this Lease.

                  In connection with Tenant's initial Building signage, Landlord
                  shall use reasonable efforts to obtain, on Tenant's behalf,
                  all necessary permits and approvals required pursuant to local
                  codes and ordinances for the building and site signage (i.e.,
                  two exterior signs on the Building and a monument sign
                  consistent with the other signs in the Park). Tenant's signage
                  on the Building shall be exclusive until such time as Tenant
                  fails to lease (including subleasing) at least one hundred
                  percent (100%) of the Building. Tenant shall reimburse
                  Landlord for the actual third-party reasonable costs and
                  expenses incurred by Landlord in connection with obtaining
                  said permits and approvals, including reasonable attorneys
                  fees and disbursements. Tenant agrees to cooperate with
                  Landlord during the permitting process by (i) promptly
                  executing the necessary documentation reasonably requested by
                  Landlord, and (ii) by furnishing the same to Landlord promptly
                  upon Landlord's request, but in no event later than seven (7)
                  days following Landlord's request. Further, the construction
                  and erection of any such signage shall be Tenant's sole
                  responsibility and at Tenant's sole cost and expense;

         6.1.19   Tenant's Authority - Tenant has the power and authority to
                  enter into this Lease and perform the obligations of Tenant
                  hereunder. This Lease and all other documents executed and
                  delivered by Tenant in connection herewith constitute legal,
                  valid, binding and enforceable obligations of Tenant; and

         6.1.20   Confidentiality - This Lease document is a confidential
                  document by and between Landlord and Tenant and Tenant agrees
                  that this Lease shall not be copied and

                                       37
<PAGE>   42

                  distributed or circulated to any person(s) other than to such
                  parties, and their respective mortgagees, successors or
                  assigns, their legal counsel or their accountants or to any
                  prospective sublessees and assignees or affiliates of Tenant,
                  or to any prospective acquirers, investors, or lenders of
                  Tenant, or to regulatory authorities, or to the directors,
                  shareholders or officers of Tenant, or as required by law,
                  without the prior written consent of Landlord. Nothing
                  contained in this Section shall prohibit the disclosure by
                  Tenant of the essential terms of this Lease.

                                   ARTICLE VII
                               CASUALTY AND TAKING

7.1      CASUALTY AND TAKING

         In case during the Term all or any substantial part of the Premises,
and/or the Building Parking Area, or any part thereof, or both (i.e. in the case
of a fire or casualty, requiring greater than twelve (12) months to rebuild in
Landlord's reasonable judgment; or in the case of a condemnation or a taking,
more than thirty-five percent (35%) of the floor area of the Premises or any
material part of the means of access thereto or more than twenty-five percent
(25%) of Building Parking Area) are damaged by fire or any other casualty or by
action of public or other authority in consequence thereof or are taken by
eminent domain Landlord shall give prompt notice, (i.e. within thirty (30) days
thereof) to Tenant (the "Landlord's Notice") and this Lease shall terminate at
Tenant's election, which may be made by notice given to Landlord within thirty
(30) days after the date of Landlord's Notice, which termination shall be
effective (i) in the event of a casualty, not less than thirty (30) nor more
than sixty (60) days after the date of notice of such termination, and (ii) in
the event of eminent domain event, as of the date on which such taking becomes
effective and Tenant is deprived of the use and enjoyment of the Premises, or
part thereof, and/or the Building Parking Area, or part thereof. If in any such
case the Lease is not so terminated, Landlord shall proceed promptly and use due
diligence to put the Premises, or part thereof, and/or the Building Parking
Area, or part thereof, or in case of taking, what may remain thereof (excluding
any items installed by Tenant which Tenant may be permitted to remove upon the
expiration of the Term) into as near as possible to the condition and character
thereof prior to such damage or taking, and in any event shall apply all
insurance proceeds or eminent domain awards received by it toward such work, for
use and occupation to the extent permitted by the net award of insurance plus
any deductibles and such amounts as Tenant may elect to make available for such
work as hereinafter provided, or the amount of the eminent domain award, and an
equitable proportion of the Fixed Rent and additional rent according to the
nature and extent of the injury shall be abated until the Premises or such
remainder and the Building Parking Area shall have been put by Landlord in such
condition; and in case of a taking which permanently reduces the area of the
Premises, an equitable proportion of the Fixed Rent and additional rent shall be
abated for the remainder of the Term and an appropriate adjustment shall be made
to the Annual Estimated Operating Costs and other additional rent payable
hereunder.

                                       38
<PAGE>   43
         However, in the case of a casualty, if such damage is not repaired and
the Premises, or portion thereof, and/or Building Parking Area or part thereof,
restored to the same condition as they were prior to such damage within twelve
(12) months from the date of Landlord's Notice, then Tenant, within thirty (30)
days from the expiration of such twelve (12) month period or from the expiration
of any extension thereof by reason of any Tenant's Delay (as defined in Section
3.2 hereof) and/or Force Majeure (as defined in Section 3.5 hereof and subject
to the provisions set forth below) as hereinafter provided, may terminate this
Lease by notice to Landlord and Landlord's mortgagee(s), given in accordance
with Section 10.3 hereof, specifying a date not more than thirty (30) days after
the giving of such notice on which the Term of this Lease shall terminate.
Notwithstanding such termination notice by Tenant, in the event that Landlord
repairs such damage and restores the Premises to the same condition prior to
such casualty during such period, not to exceed thirty (30) days, as specified
in Tenant's notice, then such notice of termination given by Tenant to Landlord
hereunder shall be null and void and of no further force or effect. The period
within which the required repairs may be accomplished hereunder shall be
extended by (a) the number of days lost as a result of a Tenant's Delay, as
defined in and subject to the provisions of Section 3.2, with such term,
however, relating to restoration or repair as referenced herein and not to the
initial construction of the Building, and (b) the number of days lost as a
result of Force Majeure, as defined in Section 3.5 (up to a maximum of
forty-five (45) days in the aggregate as aforesaid).

         If less than a substantial part of the Premises or Lot, or portion
thereof, and/or the Building Parking Area, or portion thereof (i.e. in the case
of a fire or casualty, requiring less than twelve (12) months to rebuild in
Landlord's reasonable judgment; or in the case of a condemnation or taking
thirty-five percent (35%) or less of the floor area of the Premises or any part
of the means of access thereto or twenty-five percent (25%) or less of the
Building Parking Area) are damaged by fire or any other casualty or are taken by
eminent domain, then Landlord shall give prompt notice (i.e. within thirty (30)
days) thereof to Tenant, which notice shall specify Landlord's estimation of the
time period within which such repairs shall be completed, and thereafter
Landlord shall proceed promptly and with due diligence to the extent permitted
by the net award of insurance plus any deductible amounts and such amount as
Tenant may elect to make available for such work as hereinafter provided, or the
amount of the eminent domain award. In the event that Landlord fails to repair
such damage and restore the Premises to substantially the same condition prior
to such fire and other casualty within the time period as reasonably estimated
by Landlord, but in no event greater than such twelve (12) month period from the
date of such Landlord's notice to Tenant, or any extension thereof permitted for
delays lost due to any Tenant's Delay and/or Force Majeure (as hereinbefore
provided), then Tenant may terminate this Lease by written notice to Landlord
and to Landlord's mortgagee(s), as provided in Section 10.3 hereof, specifying a
date not more than thirty (30) days after the giving of such notice on which the
Term of this Lease shall terminate. Notwithstanding such termination notice by
Tenant, in the event that Landlord repairs such damage and restores the Premises
to substantially the same condition prior to such fire or other casualty during
such period, not to exceed thirty (30) days, as specified in Tenant's notice,
then such notice of termination given by Tenant to Landlord hereunder shall be
null and void and of no further force and effect. If less than a substantial
part of the Premises and/or the Building Parking Area shall

                                       39
<PAGE>   44
be so damaged, then Fixed Rent and additional rent due hereunder shall be
equitably abated until the Premises and/or the Building Parking Area are so
restored as set forth hereunder.

         Landlord's architect's certificate, given in good faith, shall be
deemed conclusive statements therein contained and binding upon Tenant with
respect to the performance and completion of any repair or restoration work
undertaken by Landlord pursuant to this Section, except in the event of
disagreement between Landlord and Tenant relating to this Section, in which
event the dispute resolution provisions of Section 3.6 shall apply.

         Notwithstanding any language to the contrary, Landlord may construct
"Replacement Parking" pursuant to the following: If not more than thirty-five
percent (35%) of the Building Parking Area shall be so damaged, taken,
appropriated, or condemned as aforesaid, then Landlord or Tenant may elect to
provide Replacement Parking and render Tenant's notice of termination nugatory
(if applicable) by, within thirty (30) days following the effective date of such
destruction, taking, appropriation or condemnation, giving to Tenant notice in
writing that Landlord will, at Landlord's expense, construct replacement parking
spaces of the same quantity and quality and convenience as the parking spaces so
taken, appropriated or condemned (i.e., Landlord using best efforts to locate
the replacement parking spaces as close to the Building as possible). Any of
such Replacement Parking shall be constructed by Landlord within a reasonable
time period following the effective date of such destruction, taking,
appropriation or condemnation, but in no event later than thirty (30) days after
the occurrence of such destruction, taking, appropriation or condemnation, it
being agreed by Landlord and Tenant that such time period shall be extended to
include weather-related delays as aforesaid, in which event such Replacement
Parking will be completed as reasonably possible thereafter, Landlord agreeing
to proceed promptly and with due diligence to complete construction of any
Replacement Parking. Landlord and Tenant acknowledge that if Landlord is
prevented from performing the final paving for said Replacement Parking on
account of weather, such final paving may be performed as soon thereafter as is
feasible. Such notice shall be accompanied by (A) a site plan showing (i) the
location of the Replacement Parking spaces, and (B) an opinion from counsel for
Landlord that such Replacement Parking may be constructed as-of-right under then
applicable zoning and land use regulations.

         In the event of any other taking of the Premises, or any part thereof,
for temporary use or for less than one (1) year, (i) this Lease shall be and
remain unaffected thereby; and (ii) Landlord shall pay to Tenant its pro rata
share of any such use, provided that if any taking is for a period extending
beyond the Term of this Lease, such award shall be appointed between Landlord
and Tenant as of the Term Expiration Date.

         Tenant has the option but not the obligation, in any fire or other
casualty which creates a Landlord repair obligation in accordance with the terms
of this Section to make available for such reconstruction all or a portion of
the amount by which the cost of repair as certified by Landlord's architect
exceeds the amount of proceeds received by Landlord.

                                       40
<PAGE>   45
7.2      RESERVATION OF AWARD

         Landlord reserves to itself any and all rights to receive awards made
for damages to the Premises or Lot and the leasehold hereby created, or any one
or more of them, accruing by reason of exercise of eminent domain or by reason
of anything lawfully done in pursuance of public or other authority. Tenant
hereby releases and assigns to Landlord all Tenant's rights to such awards, and
covenants to deliver such further assignments and assurances thereof as Landlord
may from time to time request. It is agreed and understood, however, that
Landlord does not reserve to itself, and Tenant does not assign to Landlord, any
damages payable for (i) movable trade fixtures installed by Tenant or anybody
claiming under Tenant, at its own expense, or (ii) relocation expenses
recoverable by Tenant from such authority in a separate action, or (iii) the
value of Tenant's improvements installed in the Premises by or on behalf of
Tenant, but not by Landlord.

7.3      ADDITIONAL CASUALTY PROVISIONS

         (a) Landlord shall not be required to repair or replace any of Tenant's
business machinery, equipment, cabinet work, furniture, personal property or
other installations not originally installed by Landlord.

         (b) In the event of any termination of this Lease pursuant to this
Article VII, the Term of this Lease shall expire as of the effective termination
date as fully and completely as if such date were the date herein originally
scheduled as the Term Expiration Date, and Landlord shall assist Tenant to the
extent necessary to secure Tenant's share of any insurance award relative to the
Tenant's Work hereunder. Tenant shall have access to the Premises at Tenant's
sole risk for a period of thirty (30) days after the date of termination in
order to remove Tenant's personal property except as prohibited by any
applicable governmental agency or official.

         (c) Notwithstanding any language to the contrary contained in this
Article VII, if all or any substantial part of the Premises and/or the Building
Parking Areas or any part thereof (as hereinabove defined), shall be damaged by
fire or other casualty or taken by eminent domain during the last two (2) years
of the Term of this Lease or the last two (2) years of either of the Extended
Terms, as the case may be, then either Landlord or Tenant may terminate this
Lease effective as of the date of such fire or other casualty or taking upon
notice to the other as aforesaid, except that Tenant may render Landlord's
notice of termination nugatory by exercising early its option to extend the
initial Term, or the applicable Extended Term, as the case may be, of this Lease
for five (5) additional years in accordance with Exhibit F. In the event of such
early exercise, Landlord and Tenant agree to determine the Fixed Rent for the
applicable Extended Term at least nine (9) months prior to the commencement date
of the applicable Extended Term in accordance with and in the manner set forth
in said Exhibit F.

         (d) Notwithstanding any language contained in this Article VII of this
Lease, in the event that the Phase I Lease (as defined in Sections 3.1.1 hereof)
is terminated due to a casualty or taking as provided in Article VII of the
Phase I Lease, then Tenant shall also have the right to terminate this Lease
(i.e. the Phase II Lease) at the time of termination of the Phase I Lease.

                                       41
<PAGE>   46
                                  ARTICLE VIII
                               RIGHTS OF MORTGAGEE

8.1      PRIORITY OF LEASE

         Landlord shall have the option to subordinate this Lease to any
mortgagee or deed of trust of the Lot or Premises, or both ("the mortgaged
premises"), provided that the holder thereof enters into a Subordination,
Non-Disturbance and Attornment Agreement substantially in the form attached
hereto as Exhibit J (or such other form mutually agreeable to Landlord, Tenant
and Landlord's mortgagee, each party agreeing to reasonably cooperate with each
other in reaching mutual agreement on the content of any such other form, so
long as such other form does not substantially reduce or alter Tenant's rights
or obligations thereunder).

8.2      LIMITATION ON MORTGAGEE'S LIABILITY

         Upon entry and taking possession of the mortgaged premises for any
purpose other than foreclosure, the holder of a mortgage shall have all rights
of Landlord, and during the period of such possession, the duty to perform all
Landlord's obligations hereunder. Except during such period of possession, no
such holder shall be liable, either as mortgagee or as holder of a collateral
assignment of this Lease, to perform, or be liable in damages for failure to
perform any of the obligations of Landlord unless and until such holder shall
enter and take possession of the mortgaged premises for the purpose of
foreclosing a mortgage. Upon entry for the purpose of foreclosing a mortgage,
such holder shall be liable to perform all of the obligations of Landlord,
subject to the provisions of Section 8.3 provided that a discontinuance of any
foreclosure proceeding shall be deemed a conveyance under the provisions of
Section 10.4 to the owner of the equity of the mortgaged premises. From and
after making entry and taking possession of the Premises, any such mortgagee
shall be fully and completely liable for the obligations hereunder.

8.3      MORTGAGEE'S ELECTION

         Intentionally Deleted.

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<PAGE>   47
8.4      NO PREPAYMENT OR MODIFICATION, ETC.

         No Fixed Rent, additional rent, or any other charge shall be paid more
than thirty (30) days prior to the due dates thereof, and payments made in
violation of this provision shall (except to the extent that such payments are
actually received by a mortgagee in possession or in the process of foreclosing
its mortgage) be a nullity as against such mortgagee. No assignment of this
Lease (excepting only in accordance with the provisions of this Lease) and no
agreement to make or accept any surrender, termination or cancellation of this
Lease (excepting only in accordance with the provisions of this Lease) and no
agreement to modify so as to reduce the rent, change the Term, or otherwise
materially change the rights of Landlord under this Lease, or to relieve Tenant
of any obligations or liability under this Lease, shall be valid unless
consented to in writing by Landlord's mortgagees of which Tenant has received
notice.

8.5      NO RELEASE OR TERMINATION

         No act or failure to act on the part of Landlord which would entitle
Tenant under the terms of this Lease, or by law, to be relieved of Tenant's
obligations hereunder or to terminate this Lease, shall result in a release or
termination of such obligations or a termination of this Lease unless (i) Tenant
shall have first given thirty (30) days prior written notice of Landlord's act
or failure to act to Landlord's mortgagees of which Landlord has provided
written notice to Tenant, if any, specifying the act or failure to act on the
part of Landlord which could or would give basis to Tenant's rights, and (ii)
such mortgagees, after receipt of such notice, have failed or refused to correct
or cure the condition complained of within a reasonable time thereafter, but
nothing contained in this Section 8.5 shall be deemed to impose any obligation
on any such mortgagee to correct or cure any such condition. "Reasonable time"
as used above means and includes a reasonable time to obtain possession of the
mortgaged premises, if the mortgagee elects to do so, and a reasonable time to
correct or cure the condition if such condition is determined to exist, however,
in no event shall such time extend beyond sixty (60) days from the date Tenant
provides notice to Landlord's mortgagee(s) as aforesaid.

8.6      CONTINUING OFFER

         The covenants and agreements contained in this Lease with respect to
the rights, powers and benefits of a mortgagee (particularly, without limitation
thereby, the covenants and agreements contained in this Article VIII) constitute
a continuing offer to any person, corporation or other entity, which by
accepting or requiring an assignment of this Lease or by entry or foreclosure
assumes the obligations herein set forth with respect to such mortgagee, and
such mortgagee shall be entitled to enforce such provisions in its own name.
Tenant agrees on request of Landlord to execute and deliver from time to time
any agreement which may reasonably be deemed necessary to implement the
provisions of this Article VIII.

                                       43
<PAGE>   48
8.7      SUBMITTAL OF FINANCIAL STATEMENT

         At any time, but not more than annually during the Term of this Lease,
and only to the extent Tenant becomes a publicly traded company, within fifteen
(15) days after request therefor by Landlord (i.e. if requested by Landlord'
mortgagee(s)), Tenant shall supply to Landlord and/or any mortgagee of Landlord
a current financial statement, which such financial statement may be given by
Tenant to Landlord in the form of Tenant's current annual report, or such other
financial information as may be reasonably required by any such party. Landlord
agrees to use diligent efforts to keep such information confidential and to
request Landlord's mortgagee to keep such information confidential.

                                   ARTICLE IX
                                     DEFAULT

9.1      EVENTS OF DEFAULT BY TENANT

         It shall be an Event of Default under this Lease, if (i) Tenant fails
to pay Fixed Rent or additional rent for more than ten (10) days, after notice
thereof specifying such failure and that such failure may be an Event of Default
hereunder; (ii) Tenant fails to perform its other non-monetary obligations
hereunder for more than thirty (30) days after notice thereof from Landlord,
together with such additional time, if any, as is reasonably required to cure
the default if the default is of such a nature that it cannot reasonably be
cured in thirty (30) days; or (iii) if Tenant makes any assignment for the
benefit of creditors, or files a petition under any bankruptcy or insolvency
law; or (iv) if such a petition is filed against Tenant and is not dismissed
within sixty (60) days; or (v) if a receiver becomes entitled to Tenant's
leasehold hereunder and it is not returned to Tenant within ninety (90) days; or
(vi) such leasehold is taken on execution or other process of law in any action
against Tenant; or (vii) if there is a continuing, uncured Event of Default
under the Phase I Lease (as defined in Section 3.1.1 hereof); then, and in any
such cases, Landlord and the agents and servants of Landlord may, in addition to
and not in derogation of any remedies for any preceding breach of covenant,
immediately or at any time thereafter while such default continues and without
further notice, enter into and upon the Premises or any part thereof in the name
of the whole or mail a notice of termination addressed to Tenant at the Premises
and repossess the same as of Landlord's former estate and expel Tenant and those
claiming through or under Tenant and remove its and their effects without being
deemed guilty of any manner of trespass and without prejudice to any remedies
which might otherwise be used for arrears of rent or prior breach of covenant,
and upon such entry or mailing as aforesaid, this Lease shall terminate, but
Tenant shall remain liable as hereinafter provided. After the occurrence of an
Event of Default as aforesaid, Tenant hereby waives all statutory rights of
redemption, if any to the extent such rights may be lawfully waived, and
Landlord, without notice to Tenant, may store Tenant's effects and those of any
person claiming through or under Tenant at the expense and risk of Tenant and,
if Landlord so elects, may sell such effects at public auction or private sale
and apply the net proceeds to the payment of all sums due to Landlord from
Tenant, if any, and pay over the balance, if any, to Tenant.

                                       44
<PAGE>   49
9.2      TENANT'S OBLIGATIONS AFTER TERMINATION

         In the event that this Lease is terminated under any of the provisions
contained in Section 9.1, Tenant covenants to pay forthwith to Landlord, as
compensation, a single lump-sum payment equal to the excess of the net present
value of the total rent reserved for the residue of the Term (exclusive of any
unexercised Extended Term(s) remaining at the time of termination) over the fair
market rental value of the Premises (including additional rent) for said residue
of the Term estimated as of the date of termination. If Landlord does not
receive a single lump-sum payment from Tenant as aforesaid, Tenant covenants and
agrees to pay punctually to Landlord all the sums and perform all the
obligations which Tenant covenants in this Lease to pay and to perform in the
same manner and to the same extent and at the same time as if this Lease had not
been terminated. In calculating the amounts to be paid by Tenant under the
foregoing covenants, Tenant shall be credited with any amount paid to Landlord
as compensation as provided in the first sentence of this Section 9.2 and also
with the net proceeds of any rents obtained by Landlord by reletting the
Premises, after deducting all Landlord's expenses in connection with such
reletting, including, without implied limitation, all repossession costs,
brokerage commissions, reasonable fees for legal services and reasonable expense
of preparing the Premises for such reletting, it being agreed by Tenant that
Landlord may (i) relet the Premises or any part or parts thereof for a term or
terms which may, at Landlord's option, be equal to or less than or exceed the
period which would otherwise have constituted the balance of the Term and may
grant such concessions and free rent as Landlord in its sole judgment considers
advisable or necessary to relet the same, and (ii) make such alterations,
repairs and decorations in the Premises as Landlord in its sole judgment
considers advisable or necessary to relet the same, and no action of Landlord in
accordance with the foregoing on failure to relet or to collect rent under
reletting shall operate or be construed to release or reduce Tenant's liability
as aforesaid. Landlord hereby agrees in all events to use reasonable efforts and
due diligence to mitigate the foregoing damages and to relet the Premises.

         Nothing contained in this Lease shall, however, limit or prejudice the
right of Landlord to prove and obtain in proceedings for bankruptcy or
insolvency by reason of the termination of this Lease, an amount equal to the
maximum allowed by any statute or rule of law in effect at the time when, and
governing the proceedings in which, the damages are to be proved, whether or not
the amount be greater, equal to, or less than the amount of the loss or damages
referred to above.

                                    ARTICLE X
                                  MISCELLANEOUS

10.1     TITLES

         The titles of the Articles are for convenience and are not to be
considered in construing this Lease.

                                       45
<PAGE>   50
10.2     NOTICE OF LEASE

         Concurrently with the executing of this Lease, Landlord and Tenant have
executed and recorded a notice of lease in the form attached hereto as Exhibit
T. If this Lease is terminated before the Term expires the parties will execute
an instrument in such form acknowledging the date of termination.

10.3     NOTICES FROM ONE PARTY TO THE OTHER

         No notice, approval, consent requested or election required or
permitted to be given or made pursuant to this Lease shall be effective unless
the same is in writing. Communications shall be addressed, if to Landlord, at
Landlord's Address with a copy to Paul A. Hedstrom, Esq., Hinckley, Allen &
Snyder LLP, 28 State Street, Boston, Massachusetts 02109, or at such other
address as may have been specified by prior notice to Tenant and, if to Tenant,
at Tenant's Address with a copy to Diane M. McDermott, Esq., Gadsby & Hannah,
LLP, 225 Franklin Street, Boston, Massachusetts 02110 and to Suzanne M.
Zabitchuck, Esq., c/o Siemens Corporation, 200 Wheeler Road, Burlington,
Massachusetts 01803 or at such other place as may have been specified by prior
notice to Landlord. Any communication so addressed shall be deemed duly served
if actually received or delivery is refused at the foregoing addresses mailed by
registered or certified mail, return receipt requested, delivered by hand, or by
overnight express service by a carrier providing a receipt of delivery.

10.4     BIND AND INURE

         The obligations of this Lease shall run with the land, and this Lease
shall be binding upon and inure to the benefit of the parties hereto and their
respective heirs, successors and assigns, except that the Landlord named herein
and each successive owner of the Premises shall be liable only for the
obligations accruing during the period of its ownership, said liability
terminating as to future liability upon termination of such ownership and
passing to the successor in ownership. Neither the Landlord named herein nor any
successive owner of the Premises whether an individual, trust, a corporation or
otherwise shall have any personal liability beyond their equity interest in the
Premises.

10.5     NO SURRENDER

         The delivery of keys to any employees of Landlord or to Landlord's
agent or any employee thereof shall not operate as a termination of this Lease
or a surrender of the Premises.

                                       46
<PAGE>   51
10.6     NO WAIVER, ETC.

         The failure of Landlord or of Tenant to seek redress for violation of,
or to insist upon the strict performance of any covenant or condition of this
Lease or, with respect to such failure of Landlord, any of the Rules and
Regulations or Park Covenants referred to in Section 6.1.4, whether heretofore
or hereafter adopted by Landlord, shall not be deemed a waiver of such violation
nor prevent a subsequent act, which would have originally constituted a
violation, from having all the force and effect of an original violation, nor
shall the failure of Landlord to enforce any of said Rules and Regulations or
Park Covenants against any other tenant in the Park be deemed a waiver of any
such Rules or Regulations or Park Covenants, as applicable. The receipt by
Landlord of Fixed Rent or additional rent with knowledge of the breach of any
covenant of this Lease shall not be deemed a waiver of such breach by Landlord,
unless such waiver shall be in writing signed by Landlord. No consent or waiver,
express or implied, by Landlord or Tenant to or of any breach of any agreement
or duty shall be construed as a waiver or consent to or of any other breach of
the same agreement or duty in a previous or subsequent instance, or any other
agreement or duty.

10.7     NO ACCORD AND SATISFACTION

         No acceptance by Landlord of a lesser sum than the Fixed Rent and
additional rent then due shall be deemed to be other than on account of the
earliest installment of such rent due, nor shall any endorsement or statement on
any check or any letter accompanying any check or payment as rent be deemed as
accord and satisfaction, and Landlord may accept such check or payment without
prejudice to Landlord's right to recover the balance of such installment or
pursue any other remedy in this Lease provided.

10.8     CUMULATIVE REMEDIES

         The specific remedies to which Landlord may resort under the terms of
this Lease are cumulative and are not intended to be exclusive of any other
remedies or means of redress to which it may be lawfully entitled in case of any
breach or threatened breach by Tenant of any provisions of this Lease. In
addition to the other remedies provided in this Lease, Landlord shall be
entitled to the restraint by injunction of the violation or attempted or
threatened violation of any of the covenants, conditions or provisions of this
Lease or to a decree compelling specific performance of any such covenants,
conditions or provisions.

10.9     PARTIAL INVALIDITY

         If any term of this Lease, or the application thereof to any person or
circumstances shall to any extent be invalid or unenforceable, the remainder of
this Lease, or the application of such term to persons or circumstances other
than those as to which it is invalid or unenforceable, shall not be affected
thereby, and each term of this Lease shall be valid and enforceable to the
fullest extent permitted by law.

                                       47
<PAGE>   52
10.10    RIGHT TO CURE

         (a) If Tenant shall at any time fail to perform its obligation in
accordance with the provisions of this Lease and Tenant does not commence the
cure of such failure within thirty (30) days of notice thereof (except in the
event of emergencies), and thereafter diligently prosecute such cure to
completion, then Landlord shall have the right, but shall not be obligated, to
enter upon the Premises and to perform such obligation, notwithstanding the fact
that no specific provision for such substituted performance by Landlord is made
in this Lease with respect to such default. In performing such obligation,
Landlord may make any payment of money or perform any other act. All sums so
paid by Landlord (together with interest at the rate set forth in Section 4.3
hereof), and all necessary incidental reasonable third party costs and expenses
in connection with the performance of any such acts by Landlord, shall be deemed
to be additional rent under this Lease and shall be payable to Landlord
immediately on demand. Landlord may exercise the foregoing rights without
waiving any other of its rights or releasing Tenant from any of its obligations
under this Lease.

         (b) If Landlord shall have failed to perform any of Landlord's
covenants hereunder relating to the Premises (Landlord and Tenant hereby
agreeing, however, that, except as otherwise provided in Section 3.2 relating to
Tenant's right to complete the Punch List Work for its own behalf if Landlord
fails to do so, Tenant shall have no self-help rights with respect to any (i)
common areas or facilities of the Building or any other tenant's space in the
Building, if applicable (i.e. recapture by Landlord), or (ii) the Building
Parking Area, the Lot or the Common Areas of the Park within the time periods
set forth herein and Landlord does not commence the cure of such failure within
thirty (30) days of notice thereof (except in the event of emergencies), and
thereafter diligently prosecute such cure to completion, then Tenant shall have
the right, but not the obligation, to cure any such covenants for the account of
Landlord. If Tenant shall undertake such performance, Landlord shall reimburse
Tenant for all costs and expenses reasonably incurred by Tenant in connection
with such performance within twenty (20) days after receipt of an invoice
therefor from Tenant (together with any such back up documentation reasonably
requested by Landlord). If Landlord fails to reimburse Tenant within said twenty
(20) day period, then interest at the rate set forth in Section 4.3 hereof,
shall accrue on any amounts due from Landlord hereunder until such costs have
been reimbursed in full. If there remains any amounts unpaid by Landlord to
Tenant hereunder after interest has commenced to accrue for at least thirty (30)
days, then Tenant shall be entitled to offset the unreimbursed costs together
with interest thereon as aforesaid, against fifteen percent (15%) of the monthly
Fixed Rent due hereunder until such costs due to Tenant hereunder have been
reimbursed in full.

10.11    ESTOPPEL CERTIFICATE

         Tenant agrees on the Commencement Date, and from time to time
thereafter, upon not less than thirty (30) days' prior written request by
Landlord, to execute, acknowledge and deliver to Landlord a statement in writing
in substantially the form attached hereto as Exhibit G, certifying if true (and
where not true, indicating where not true), as follows: that this Lease is
unmodified and in full force and effect; that except as set forth in this Lease,
Tenant has no defenses, offsets or counterclaims against its obligations to pay
the Fixed Rent and additional

                                       48
<PAGE>   53
rent and to perform its other covenants under this Lease; that there are no
uncured defaults of Landlord or Tenant under this Lease (or, if there are any
defenses, offsets, counterclaims, or defaults, setting them forth in reasonable
detail); and the dates to which the Fixed Rent, additional rent and other
charges have been paid. Any such statements delivered pursuant to this Section
10.11 may be relied upon by any prospective purchaser or mortgage of premises
which include the Premises or any prospective assignee of any such mortgagee.

10.12    WAIVER OF SUBROGATION

         Landlord and Tenant mutually agree, with respect to any hazard which is
covered by casualty or property insurance then being carried by them, or
required to be carried hereunder (whether or not such insurance is then in
effect) to release each other from any and all claims with respect to such loss;
and they further mutually agree that their respective insurance companies shall
have no right of subrogation against the other on account thereof. If extra
premium is payable by either party as a result of this provision, the other
party shall reimburse the party paying such premium the amount of such extra
premium. The parties further agree that if said waiver of subrogation shall be
unobtainable or unenforceable or shall void the respective policies, then their
respective insurance policies shall not be invalidated, and said waiver shall
become null and void and of no further force and effect.

10.13    BROKERAGE

         Tenant represents and warrants to Landlord, and Landlord represents and
warrants to Tenant, that it has dealt with no broker, other than such brokers
listed in Section 1.1, in connection with this transaction and agrees to defend,
indemnify and save the other party harmless from and against any and all claims
for a commission arising out of this Lease made by anyone, other than such
brokers in Section 1.1. Landlord shall be responsible for, and hold Tenant
harmless with respect to, all fees and commissions payable to such brokers
specified in Section 1.1.

10.14    PARKING/TRAFFIC PERSONNEL

         Tenant's occupancy of the Premises shall include the use of 277 parking
spaces. Tenant's parking spaces shall be known and referred to in this Lease as
the "Building Parking Area", and shall be shown as such on the Landlord's Plans.
The Building Parking Area shall be used by Tenant in common with other tenants
of the Building, if applicable, including the Building described in the Phase I
Lease, including without limitation, tenant(s) described in the Phase I Lease
(as defined in Section 3.1.1 hereof).

         Upon Tenant giving Landlord at least SIXTY (60) days prior written
notice, Landlord agrees to provide traffic control personnel at peak hours,
subject to approval of the Massachusetts Highway Department and the Town of
Westford, and the cost thereof shall be reimbursable to Landlord pursuant to
Sections 4.2 and 5.1.2 hereof.

                                       49
<PAGE>   54
10.15    ACCESS

         Subject to the terms and provisions of this Lease, Tenant shall have
twenty-four (24) hours, seven (7) days per week, access to the Premises.

10.16    ENTIRE AGREEMENT

         This instrument contains the entire and only agreement between the
parties as to the Premises, and no oral statements or representations or prior
written matter not contained in this instrument shall have any force or effect.
This Lease shall not be modified in any way except by a writing subscribed by
both parties.

10.17    GOVERNING LAW

         This Lease shall be governed by and construed and enforced in
accordance with the laws and courts of the Commonwealth of Massachusetts.

10.18    ADDITIONAL REPRESENTATIONS

         Landlord represents and warrants to Tenant as follows:

         (a) that Landlord has the right and authority to enter into this Lease
and grant Tenant possession of the Premises and other rights set forth herein;

         (b) that Landlord is the fee simple owner of the Lot and that Landlord
(or its affiliate(s) or an affiliate(s) of The Gutierrez Company) are the fee
simple owners of the Park; and

         (c) that the Building (including all common areas, entrances,
restrooms, elevators, water fountains and signage), the Building Parking Area
and the Lot will, upon Substantial Completion and issuance of all necessary
permits and approvals required to be obtained from any and all necessary
governmental agencies prior to occupancy of the Premises by Tenant, including
without limitation, a certificate of occupancy from the Town of Westford which
allows Tenant to use and occupy the Building as specified in Article III hereof,
comply with all dimensional, use, parking, loading and other zoning requirements
of the Town of Westford, and all applicable building codes and governmental
requirements, including without limitation the regulations of the Americans with
Disabilities Act (ADA), and the Park Covenants attached hereto as Exhibit I.

10.19    ROOFTOP COMMUNICATION EQUIPMENT

         Subject to the provisions hereinafter provided, Tenant shall have the
right from time to time during the Term hereof to install rooftop communication
equipment (i.e. satellite or antenna devices) on the roof of the Building.
Subject to applicable law, matters of title, and the consent of Landlord (which
consent shall not be unreasonably withheld or delayed), Tenant, at its sole cost
and expense, has the right to install such equipment on the roof of the
Building. The size

                                       50
<PAGE>   55
and location of the installation shall be at a site acceptable to Landlord, and
the approval of any such size and location shall not be unreasonably withheld or
delayed by Landlord. Tenant shall install the equipment in accordance with sound
construction practices, and in accordance with all applicable laws, rules, codes
and ordinances, and in a good and workmanlike manner. Tenant shall use such
roofing contractor required to comply with the existing roof warranties, as
designated by Landlord. Tenant shall indemnify, defend and hold Landlord
harmless from and against any and all liability or loss arising from or out of
the installation or removal of such rooftop communication equipment. Upon
expiration of the Term, Tenant shall be responsible for the removal of the same
and for repairing any damage caused therefrom.

                                       51
<PAGE>   56
         IN WITNESS WHEREOF, the parties hereto have duly executed this Lease as
of this ___day of June, 2000.

                                    LANDLORD:
                                    MICHELSON FARM-WESTFORD
                                    TECHNOLOGY PARK X LIMITED
                                    PARTNERSHIP

                                    By:  The Gutierrez Company, its sole
                                         General Partner

                                    By:  /s/ Arthur J. Gutierrez
                                        ----------------------------------------
                                        Arthur J. Gutierrez, President

                                    Dated:  June 30, 2000
                                           -------------------------------------

                                    TENANT:
                                    UNISPHERE SOLUTIONS, INC.

                                    By:  /s/ Suzanne M. Zabitchuck
                                        ----------------------------------------

                                    Its:  General Counsel
                                         ---------------------------------------

                                    Dated: June 30, 2000
                                           -------------------------------------

                                       52
<PAGE>   57
                                   EXHIBIT "A"

               PLANS SHOWING TENANT'S SPACE, THE LOT AND THE PARK
                      (INCLUDING THE BUILDING PARKING AREA)

*  Sheet A1.5, A1.6 and A1.7, prepared by Symmes, Maini & McKee Associates.

*  Sheet C3 "Layout & Materials Plan (Phase II)", prepared by Symmes, Maini &
   McKee Associates.

*  Revised Subdivision Plan of Land, Westford Technology Park, Westford, Mass.,
   dated May 1, 2000, prepared by Harry R. Feldman, Inc.

*  Easement Plan, Westford Technology Park, Westford, Massachusetts, Sheets
   1-2, prepared by Harry R. Feldman, Inc., dated April 12, 2000, revised May 1,
   2000.
<PAGE>   58
                                  EXHIBIT "A-1"

                          LEGAL DESCRIPTION OF THE LOT

         Two (2) parcels of land located on Technology Park Drive in Westford,
Middlesex County, Massachusetts shown as Lot 10D and Lot 10E on that certain
plan entitled "Revised Subdivision Plan of Land, Westford Technology Park,
Westford, Mass." prepared by Harry R. Feldman, Inc., dated May 1, 2000 recorded
with the Middlesex North Registry of Deeds in Plan Book 203, Plan 47 ("the
"Plan"). Lot 10D contains 11,397 acres according to the Plan and Lot 10E
contains 3.811 acres according to the Plan (a copy of which Plan is attached
hereto and made a part hereof).
<PAGE>   59
                                  EXHIBIT "B-1"

                         PRELIMINARY BASE BUILDING PLANS

*   Phase II as shown on Plans entitled A1.5, A1.6 and A1.7, prepared by
    Symmes, Maini & McKee Associates, Inc. (Please see plans attached to
    Exhibit "A").

*   Exterior Elevations Plan (Phase II) A2.2, prepared by Symmes, Maini & McKee
    Associates, Inc.

*   Sheet C3 "Layout & Materials Plan (Phase II)", prepared by Symmes, Maini &
    McKee Associates, Inc. (Please see plan attached to Exhibit "A").
<PAGE>   60
                                 EXHIBIT "B-2"

                        GUTIERREZ CONSTRUCTION CO., INC.

                             OUTLINE SPECIFICATIONS
                                      FOR
                            WESTFORD TECHNOLOGY PARK
                                   BUILDING 10
                                     PHASE II
                             WESTFORD, MASSACHUSETTS

                                 June 19, 2000
<PAGE>   61

                             OUTLINE SPECIFICATIONS

                                     INDEX

<TABLE>
<CAPTION>
                                                                                     PAGE NO.
                                                                                     --------
<S>                                                                                  <C>
DIVISION 1 - GENERAL REQUIREMENTS                                                        3
---------------------------------
             Section 1A - Scope of the Work
             Section 1B - Assumptions
             Section 1C - Area Summary

DIVISION 2 - SITE WORK                                                                   4
----------------------
             Section 2A - Site Preparation and Earthwork
             Section 2B - Site Improvements
             Section 2C - Lawns and Plantings
             Section 2D - Site Drainage
             Section 2E - Site Utilities
             Section 2F - Irrigation

DIVISION 3 - CONCRETE                                                                    6
---------------------
             Section 3A - Concrete
             Section 3B - Precast Concrete

DIVISION 5 - METALS                                                                      7
-------------------
             Section 5A - Structural Steel
             Section 5B - Miscellaneous and Ornamental Iron

 DIVISION 6 - CARPENTRY                                                                  8
-----------------------
             Section 6A - Rough Carpentry
             Section 6B - Millwork

 DIVISION 7 - MOISTURE PROTECTION                                                        9
---------------------------------
             Section 7A - Roofing and Flashing
             Section 7B - Waterproofing, Dampproofing and Caulking

 DIVISION 8 -DOORS, WINDOWS AND GLASS                                                   10
-------------------------------------
             Section 8A - Wood Doors
             Section 8B - Metal Door Frames
             Section 8C - Finish Hardware
             Section 8D - Aluminum Entrance
             Section 8E - Glass and Glazing
             Section 8F - Overhead Doors
</TABLE>

                                       1
<PAGE>   62

Outline Specifications - Index

<TABLE>
<S>                                                                                     <C>
DIVISION 9 - FINISHES                                                                   12
---------------------
                Section 9A - Resilient Base
                Section 9B - Acoustical
                Section 9C - Painting and Vinyl Wallcovering
                Section 9D - Gypsum Drywall
                Section 9E - Exterior Soffits
                Section 9F - Insulation
                Section 9G - Carpeting
                Section 9H - Ceramic Tile

DIVISION 10 - SPECIALTIES                                                               14
-------------------------
                Section 10A - Toilet Partitions
                Section 10B - Toilet Accessories
                Section 10C - Dock Equipment

DIVISION 12 - FURNISHINGS                                                               15
-------------------------
                Section 12A - Blinds

DIVISION 15 - MECHANICAL                                                                17
------------------------
               Section 15A - Plumbing
               Section 15B - Heating, Ventilating and Air Conditioning
               Section 15C - Sprinklers

DIVISION 16 - ELECTRICAL                                                                20
------------------------
                Section 16A - Electrical Work

DIVISION 17 - EXCLUSIONS                                                                23
------------------------
</TABLE>

                                       2
<PAGE>   63

                                   DIVISION 1

                              GENERAL REQUIREMENTS

SECTION 1A - SCOPE OF THE WORK

1A-01     Gutierrez Construction Co., Inc. will provide all labor, material and
          equipment necessary to complete the construction of the subject
          building in accordance with these Outline Specifications dated June
          19, 2000, the preliminary drawings as prepared by Symmes, Maini &
          McKee Associates, Inc. dated 6/1/00, and the layout and material, plan
          (Phase II) as prepared by Symmes, Maini & McKee Associates, Inc.

SECTION 1B - ASSUMPTIONS

1B-01     All required utilities of adequate size and capacity will be available
          at the property line or in the Subdivision Road immediately adjacent
          to the property line.

1B-02     This proposal is based on Class II-C construction as specified in the
          Massachusetts State Building Code.

SECTION 1C - AREA SUMMARY

1C-01     The building is a three (3) story, "open shell" office building for a
          total of 75,000 square feet.

1C-02     Two Hundred Seventy Seven (277) Parking spaces to be provided.

1C-03     Add one (1) truck dock to the existing truck docks.

                                       3
<PAGE>   64

                                   DIVISION 2

                                   SITE WORK

SECTION 2A - SITE PREPARATION AND EARTH WORK

2A-01     The building site, including landscaped areas, shall be graded to
          +0-.1' elevations with positive drainage, free of pockets, using
          existing granular materials. All grading is to be done in accordance
          with the site plan developed from the preliminary drawings adjusted so
          as to produce a balanced site.

2A-02     The building pad shall be graded and compacted with six inches (6") of
          suitable granular material to an elevation of minus five inches (-5")
          from finished floor elevation. Compaction shall be 95% proctor method,
          ASTM D 1557.

2A-03     All paved areas shall receive a minimum of eight inches (8") of
          suitable granular material compacted to 92% of its maximum density.

SECTION 2B - SITE IMPROVEMENTS

2B-01     Parking areas shall be paved with two and one half inches (2 1/2") of
          bituminous concrete to consist of one and one-half inches (1 1/2")
          binder coarse and one inch (1") finish. Material and workmanship shall
          be based on State Highway Department specifications.

2B-02     Roads shall be paved as specified for parking areas.

2B-03     Sidewalks shall be paved with four inches (4") of concrete around the
          building and 2 1/2" bituminous paving at parking lots.

2B-04     All necessary curbing shall be granite or bituminous berm as shown on
          the drawings.

SECTION 2C - LAWNS AND PLANTINGS

2C-01     Lawns and planting will be similar to Westford Technology Park
          Building #1.

SECTION 2D - SITE DRAINAGE

 2D-01    Parking areas, roadways and trucking areas shall be surface drained
          and underground drainage shall be installed as required.

                                       4
<PAGE>   65

                       DIVISION 2 - SITE WORK (Continued)

SECTION 2E - SITE UTILITIES

2E-01     Domestic water service and fire sprinkler shall be from a water main
          at the property line. The water meter and piping shall be sized to
          suit the building requirements. Fire sprinkler service will be sized
          per NFPA 13 for light hazard.

2E-02     Sanitary sewer shall be connected to the existing Park sewer treatment
          system as indicated on the site plan.

2E-03     Electrical service shall be provided by the electric UTILITY COMPANY'S
          pad-mounted transformer.

2E-04     Telephone service entrance conduit shall be provided as specified by
          the local telephone company.

2E-05     Gas service will be provided by the local utility company.

SECTION 2F - IRRIGATION

2F-01     An automatic, underground lawn irrigation system will be provided for
          all lawn areas adjacent to the building and at the main entrance.

                                       5
<PAGE>   66

                                   DIVISION 3

                                    CONCRETE

SECTION 3A - CONCRETE

3A-01     Provide all plain and reinforced concrete work, including all
          necessary form work, sleeves, inserts, etc. Concrete material shall be
          3,000 p.s.i.

3A-02     Floor slab-on-grade shall be five inch (5") thick concrete reinforced
          with welded wire fabric for a live load rating of 200 p.s.f. Second
          and third floor slabs shall be designed for a load of 100 p.s.f. with
          live load reduction allowed by the Massachusetts State Code.

3A-03     Foundations shall be continuous reinforced concrete footings and walls
          and individual spread reinforced concrete footings under columns. All
          foundations shall bear on engineered fill, natural soil or ledge.

3A-04     Floors shall meet the following level and flatness criteria. Slab on
          grade shall be within FF (flatness) 25 and F1 (level) 20. Suspended
          slabs shall be within FF (flatness) = 20.

SECTION 3B - PRECAST CONCRETE

3B-01     Precast concrete exterior spandrel panels shall be designed to meet
          wind loading as required by the governing code(s) and shall have an
          exposed aggregate finish as approved by the Architect and Owner.

                                       6
<PAGE>   67

                                   DIVISION 5

                                     METALS

SECTION 5A - STRUCTURAL STEEL

5A-01     All structural steel work shall conform to the "Specifications for
          Design, Fabrication and Erection of Structural Steel for Buildings" of
          the American Institute of Steel Construction and the requirements of
          the local building code. All steel shall be ASTM-A-36.

5A-02     The structure shall be steel columns, beams or trusses, and bar
          joists. The building shall be designed in accordance with the building
          code requirements.

5A-03     The roof construction shall be 22 gauge, prime-painted metal roof
          decking. Roof shall be designed to support a live load of 35 p.s.f.
          plus the loading required for a rubber or EPDM ballasted roofing
          system.

5A-04     Second and third floor framing systems shall be designed to support a
          total (live) load of 100 p.s.f. with live load reduction allowed by
          the Massachusetts State Code. Floor decking shall be 28 gauge Fab-Form
          metal deck or equal.

5A-05     Provide thirteen feet (13'-0") from first floor slab to second floor
          slab. Provide thirteen feet (13'-0") from second floor slab to the
          third floor slab. Provide thirteen feet six inches (13'-6") from third
          floor slab to the top of the roof steel.

5A-06     Provide wind framing and attachment for precast concrete.

5A-07     Provide framing and supports for roof top equipment as may be
          required.

SECTION 5B - MISCELLANEOUS AND ORNAMENTAL IRON

5B-01     Provide manhole and catch basin frames and covers where required.

5B-02     Stair shall be metal pan, concrete filled type. Stair shall be
          provided with integral nosings. Handrails shall be tubular steel,
          except as otherwise indicated on the drawings.

5B-03     All necessary channel iron supports and hanging rods for toilet
          partitions and glass entrances shall be provided.

5B-04     Provide one ornamental stair from the first to the second floor at the
          Atrium.

                                       7
<PAGE>   68

                                   DIVISION 6

                                   CARPENTRY

SECTION 6A - ROUGH CARPENTRY

6A-01     Provide all wood blocking and rough carpentry required.

6A-02     Install wood doors, metal door frames and finish hardware.

6A-03     Install toilet partitions.

SECTION 6B - MILLWORK

6B-01     All men's and women's toilet rooms shall have Corian lavatory counter
          tops with integral bowls, backsplash, endsplash and apron.

6B-03     Provide a four inch (4") oak base at the walls of the lobbies and
          toilet room vestibule areas, or alternate type base as selected.

6B-04     Provide a plastic laminate sill at all perimeter wall office windows.

6B-05     Provide a plastic laminate backsplash at the mop sink in the janitor's
          closet.

                                       8
<PAGE>   69

                                   DIVISION 7

                              MOISTURE PROTECTION

SECTION 7A - ROOFING AND FLASHING

7A-01     The roof shall be insulated to yield a "U" factor of.06. Roof loading
          is to be in accordance with the building code requirements. The
          roofing shall be a ballasted rubber or EDPM roofing system as
          manufactured by Carlysle, Firestone, General Tile or approved equal. A
          ten (10) year labor and material and an additional ten (10) years on
          material, manufacturer's standard guarantee is included.

7A-02     Flashing at the precast concrete parapets and HVAC equipment shall be
          provided.

7A-03     Vent pipe flashings shall be provided as necessary.

SECTION 7B - WATERPROOFING, DAMPPROOFING AND CAULKING

7B-01     Interior caulking shall be the type appropriate for the application.

7B-02     Caulk perimeter of all exterior doors and windows with monolastic,
          meric Thiokol caulking or approved equal.

7B-03     All precast concrete joints shall be caulked with monolastomeric
          Thiokol caulking or approved equal.

7B-04     Waterproof and/or dampproof the elevator pit as required.

                                       9
<PAGE>   70

                                   DIVISION 8
                            DOORS, WINDOWS AND GLASS

SECTION 8A - WOOD DOORS

8A-01     Interior base building wood doors shall be 3'0" x 8'-0" by 1 3/4"
          solid core, plain sliced, red oak and/or 3'0" x 7'0" by 1 3/4" solid
          core, stain grade oak. Provide fire rated doors as required by code.
          All oak doors are to have matching edges.

SECTION 8B - METAL DOORS AND FRAMES

8B-01     All interior base building door frames shall be welded type or three
          piece, pressed metal, single and/or double rabbet door frames with
          proper anchors for partitions. Provide fire rated frames as required
          by code.

SECTION 8C - FINISH HARDWARE

8C-01     Finish hardware shall be heavy duty grade Russwin, Schlage, or
          approved equal.

8C-02     Key schedule shall be per the Owner's requirements.

8C-03     Lockset to have removable cores.

8C-04     Provide electric strikes at exterior doors.

SECTION 8D - ALUMINUM ENTRANCE

8D-01     Aluminum door frame assemblies, including window trim, shall be
          anodized aluminum as indicated on the drawings.

8D-02     Aluminum entrances shall be complete with all hardware (pivot hinges,
          push/pulls, closers, etc.) except cylinder, which is to be furnished
          under Section 8C, Finish Hardware.

8D-03     Provide electric strikes at exterior doors.

SECTION 8E - GLASS AND GLAZING

8E-01     Glass for entrances shall be 1/4" tinted. Entrance doors shall be 3'0"
          x 7'0" with glass transom.

8E-02     Mirrors shall be provided over each lavatory at the men's and women's
          toilet rooms. In addition, women's toilet rooms shall be provided with
          a full height mirror located on the wall opposite the lavatories.

8E-03     The exterior glass shall be 1" insulating, tinted as manufactured by
          LOF, PPG or approved equal. Glass area shall be kept under 50% of the
          exterior wall area. Includes Manufacturer's Standard ten (10) year
          warranty for the insulated glass units.

                                       10
<PAGE>   71

               DIVISION 8 - DOORS, WINDOWS AND GLASS (Continued)

SECTION 8E - GLASS AND GLAZING (Continued)

8E-04     The aluminum framing for glass shall be anodized aluminum with a
          thermal break as manufactured by Alumiline, Kawneer or approved equal.
          All windows are to be the fixed type.

SECTION 8F - OVERHEAD DOORS

8F-01     Provide one (1) electrically operated, 8' x 8', insulated overhead
          door with weather seal for the truck dock.

                                       11
<PAGE>   72

                                   DIVISION 9

                                    FINISHES

SECTION 9A - RESILIENT BASE FOR THE BASE BUILDING

9A-01     Resilient base shall be 4" high, vinyl cove or straight as applicable.

SECTION 9B - ACOUSTICAL WORK FOR THE BASE BUILDING

9B-01     All base building toilet rooms, stairways and main lobby shall have
          lay-in, reveal edge units of 3/4" x 24" x 24", mineral acoustic tile.
          Suspension system shall be exposed grid "T" suspension system. Ceiling
          height shall be 9'-0", except toilet rooms shall be 7'6". Tile and
          suspension system shall be white.

SECTION 9C - PAINTING FOR THE BASE BUILDING

9C-01     All exposed ferrous metals shall receive a primer coat and one coat of
          enamel.

9C-02     Interior painted walls are to receive two coats of latex paint. The
          lobby will be painted with Zolatone, polymix or approved equal.

9C-03     Interior, base building doors shall receive two coats of semi-gloss
          enamel paint, or one coat of sealer and two coats of polyurethane.

9C-04     Toilet room walls that are not to receive ceramic tile shall be
          painted with Zolatone, polymix or approved equal, or shall receive
          vinyl wall covering at the contractor's option.

SECTION 9D - GYPSUM DRYWALL FOR THE BASE BUILDING

9D-01     Interior, ceiling high partitions shall be 25 ga., 2 1/2" galvanized
          metal studs, 24" O.C. with 5/8" gypsum wallboard on each side, taped,
          sanded and ready for paint. All full-height partitions shall be 25
          ga., 3 5/8" galvanized metal studs, 24" O.C. with 5/8' gypsum
          wallboard on each side, taped, sanded and ready for paint. Insulation
          in partitions shall be as indicated on the drawings. Provide fire
          rating as required by code. All required fire rated walls shall be
          constructed with approved fire rated drywall assembly systems.

9D-02     The interior of the exterior walls shall be furred with metal studs,
          insulated and covered with drywall in all finished areas. The interior
          face of all precast concrete will be insulated with a minimum of
          3 1/2" of fiberglass insulation.

                                       12
<PAGE>   73

                       DIVISION 9 - FINISHES (Continued)

SECTION 9D - GYPSUM DRYWALL FOR THE BASE BUILDING (Continued)

9D-03     Interior steel columns will be tubular type, or "H" columns covered
          with drywall, taped, sanded and prepared for finish or exposed tube
          type.

SECTION 9E - EXTERIOR SOFFITS

9E-01     All exposed exterior soffits shall be synthetic plaster.

SECTION 9F - INSULATION

9F-01     Fiberglass blanket type insulation shall be provided behind all
          exterior walls, except behind the spandrel panels where rigid
          insulation may be used.

9F-02     Rigid insulation shall be provided at the perimeter foundation walls.

SECTION 9G - CARPETING

9H-01     An allowance of twenty-four dollars ($24.00) per square yard has been
          included for all carpet at the base building areas.

SECTION 9H - CERAMIC TILE

9I-01     Toilet rooms and showers shall have 1" x 1", unglazed, ceramic floor
          tile and 4 1/4" x 4 1/4" glazed, ceramic tile, full height, at wet
          walls.

                                       13
<PAGE>   74

                                  DIVISION 10

                                  SPECIALTIES

SECTION 10A - TOILET PARTITIONS

10A-01    Partitions shall be ceiling hung with a baked enamel finish. Provide
          toilet partitions as indicated on the drawings.

SECTION 10B - TOILET ACCESSORIES

10B-01    Provide brushed stainless steel accessories as indicated on the
          drawings. Accessories shall include double roll toilet paper holders,
          recessed paper towel dispenser/disposals, liquid soap dispensers,
          sanitary napkin vendors and disposals and grab bars at handicap
          toilets. Also, provide mop hooks at janitor's closets.

SECTION 10C - DOCK EQUIPMENT

10C-01    Provide one (1) mechanical 20,000 pound capacity dock levelers. Dock
          bumper integral with the dock leveler shall be provided. Truck dock
          will be standard 48" height. Also, provide seals and/or shelters,
          swivel dock lights and bollards.

                                       14
<PAGE>   75

                                   DIVISION 12

                                   FURNISHINGS

SECTION 12A - BLINDS

12A-01    Vertical blinds shall be LouverDrape, Model EL (Elite) or approved
          equal, both traversing and rotating types.

12A-02    Blinds shall have top track only with manufacturer's standard baked
          enamel finish.

12A-03    Vertical blind blades are to be PVC solid core, 3 1/2" wide, .03"
          thickness. Color shall be manufacturer's standard color as selected by
          the Owner and Architect.

12A-04    Blinds shall be installed at all exterior wall windows.

                                       15
<PAGE>   76

                                   DIVISION 15

                                   MECHANICAL

DIVISION 15A - PLUMBING

15A-01    CODES, ORDINANCES AND PERMITS

          1.   All material and workmanship shall be in strict accordance with
               the following codes:

               A. Massachusetts State Plumbing Code
               B. Massachusetts State Building Code
               C. National Fire Codes
               D. Requirements of the Town of Westford, Massachusetts
               E. Department of Public Health

15A-02    SANITARY WASTE AND VENT SYSTEM
          1.   Interior waste and vent piping shall convey wastes to the
               underground sanitary waste system and shall be vented through the
               roof as required by code.

          2.   Exterior sanitary waste shall be connected to the existing Park
               sewer treatment system as indicated on the site plan.

15A-03    ROOF DRAINAGE SYSTEM
          1.   Interior roof drains shall be adequately sized and installed to
               drain all roof surfaces and shall be connected to the storm drain
               outside the building line.

15A-04    COLD AND HOT WATER SYSTEMS
          1.   Cold and hot water systems shall be installed to service all
               fixtures and equipment indicated on the drawings requiring cold
               and hot water.

          2.   Cold and hot water shall be sized in accordance with the latest
               requirements of the applicable plumbing code.

          3.   Provide isolation valves at each toilet room by floor.

15A-05    GAS PIPING
          1.   Provide gas piping from the meter to the rooftop HVAC Unit.

15A-06    PIPING AND FITTINGS
          1.   Piping and fittings shall be cast iron for sanitary and storm,
               and copper for water - all conforming to the latest ASTM and/or
               F.S. standards.

15A-07    PIPING AND DRAINAGE ACCESSORIES
          1.   Roof drains, wall/ground hydrants, cleanouts, and fixture
               carriers shall be as manufactured by J.R. Smith, Josam, Zurn or
               approved equal. Pressure-reducing valves and back flow preventors
               shall be as manufactured by Watts or approved equal.

                                       16
<PAGE>   77

                      DIVISION 15 - MECHANICAL (Continued)

SECTION 15A - PLUMBING (Continued)

15A-08    INSULATION
          1.   All above-ground cold water piping, valves and fittings shall be
               insulated, including the air chamber. Horizontal rain leaders and
               all roof drains shall be insulated.

15A-09    WATER METER
          1.   Water meter and piping shall be furnished and installed in
               accordance with the Town of Westford, Massachusetts'
               requirements.

15A-10    PLUMBING FIXTURES
          1.   Water closets shall be wall-hung, elongated, flush valved closets
               with 1 1/2" top spuds and exposed valves as manufactured by
               Kohler Company or approved equal, with white, open front seats,
               no cover.
          2.   Urinals shall be wall-hung, white with 1 1/2" top spuds, exposed
               valves as manufactured by Kohler Company or approved equal.
          3.   Lavatories shall be drop-in, counter type.
          4.   Drinking fountains (one on each floor) shall be electric,
               semi-recessed, wallmounted type as manufactured by Halsey Taylor
               or approved equal.
          5.   Electric hot water heater(s), sized to suit the base building
               requirements, shall be provided.
          6.   Handicap type fixtures will be provided in the toilet rooms as
               required by applicable codes.

15A-11    TESTING
          1.   All piping systems shall be tested in accordance with the
               applicable codes.

SECTION 15B - HEATING, VENTILATING AND AIR CONDITIONING

15B-01    Provide rooftop, variable volume, heating, ventilating and air
          conditioning to provide comfort heating and cooling on a year-round
          basis with controlled night set back and economizing features, and
          shall meet all applicable code requirements. Capacity will be based on
          325 S.F./Ton. Equipment shall be as manufactured by Carrier, Trane or
          approved equal as selected by Gutierrez Construction Co., Inc. A low
          voltage, automatic temperature control system will also be provided.
          Include an override switch for each rooftop unit to allow after hours
          operation. Includes HVAC distribution for the base building areas.
          Does not include HVAC distribution at tenant areas. The rooftop HVAC
          Units will provide gas fired morning warm-up to meet the requirements
          of the Massachusetts Energy Code. The rooftop HVAC Units will be
          provided with three feet (3') high vibration/insulated curbs to
          minimize noise and vibration. Rooftop units will not be operated
          without filters. Filters used during construction will be changed
          prior to Tenant's occupancy. The ventilation for the building will be
          designed per the Massachusetts State Code.

                                       17
<PAGE>   78

                      DIVISION 15 -MECHANICAL (Continued)

SECTION 15B - HEATING, VENTILATING AND AIR CONDITIONING (Continued)

15B-02    DUCT WORK

          All duct work shall be galvanized steel to meet the ASHRAE standards.
          Flexible duct run-outs shall not exceed six feet (6').

15B-03    GRILLES AND DIFFUSERS

          As required for the base building.

15B-04    TOILET ROOM EXHAUST

          A toilet room exhaust system shall be installed in accordance with the
          code requirements.

15B-05    NOISE LEVELS
          The HVAC System will be designed to meet or exceed an NCR of 35 to 40.

15B-06    HEATING, VENTILATING AND AIR CONDITIONING FOR TENANT AREAS

          A zoned heating, ventilating and air conditioning system, including
          distribution duct work, diffusers, return air grilles and thermostatic
          control for general office use is not included. Duct shafts and ducts
          will be provided from the rooftop equipment to the first and second
          floors. Above the ceiling will be used as a return air plenum. Return
          ductwork is not anticipated.

SECTION 15C - SPRINKLERS

15C-01    An automatic wet pipe, light hazard sprinkler system shall be provided
          for the base building. System shall be designed to meet the I.S.O. and
          NFPA #13 requirements. Heads at acoustical ceilings shall be chrome
          plated, semi-recessed, pendant type located at the center one third
          (1/3) of the 24" x 24" ceiling tile. Heads in open areas shall be the
          brass upright type. Testing shall be in accordance with NFPA Pamphlet
          No. 13. Furnish and install tamper and flow switches. Wiring shall be
          by the electrical subcontractor. Sprinkler distribution for the tenant
          areas is not included. Stub outs will be provided on each floor.
          Includes standpipe and fire hose cabinets as required.

                                       18
<PAGE>   79

                                  DIVISION 16

                                   ELECTRICAL

SECTION 16A - ELECTRICAL WORK

16A-01    SERVICE ENTRANCE

          The primary electric service and pad mounted transformer will be
          provided by the local utility company at no cost to Gutierrez
          Construction Co., Inc. Provide underground PVC conduit for electric
          and telephone as required by the utility companies. The secondary side
          of the electrical service will be 1,500 Amps at 480 Volt, 3-phase,
          4-wire. Provide empty conduit from the pad mounted transformer to the
          switchgear. When the Tenant's additional electrical requirements are
          determined, the main service size, feeder circuits and equipment will
          be increased at the Tenant's cost.

16A-02    CODES AND STANDARDS

          Materials and workmanship shall conform with the latest editions of
          the following applicable codes, standards and specifications:

          1.   National Board of Fire Underwriters
          2.   Underwriter's Laboratories, Inc.
          3.   National Electrical Code
          4.   National Bureau of Standards Handbook 11-30, National Safety Code
          5.   Local and State Building Codes, and all other authorities having
               jurisdiction

16A-03    RACEWAYS AND CONDUCTORS

          Generally, wiring will consist of insulated conductors installed in
          3/4" minimum size, EMT. Flexible conduit (BX) will be used for
          terminal connection at all motors. Electrical metallic tubing will be
          used in areas above hung ceilings. Aluminum conduit may be used in
          concealed areas or in areas eight feet (8') above the floor. No
          aluminum conduit will be used in concrete or underground. BX may be
          used where allowed by applicable codes. Above the ceiling is used as a
          return air plenum. Conductors will be 600 volt copper, except where
          otherwise noted. Wire/cable #2 and larger may be aluminum. The
          following conductors will be used:

          1.   Power:         #12 Minimum 75[degrees]C THWN

          2.   Lighting:      #12 Minimum 75[degrees]C THWN

          3.   Control:       #14 Minimum 75[degrees]C THW

          4.   Fixture:       #16 Minimum 90[degrees]C MTW

          5.   Alarm:         #14 Minimum 75[degrees]C THW

                                       19
<PAGE>   80

                      DIVISION 16 - ELECTRICAL (Continued)

SECTION 16A - ELECTRICAL WORK (Continued)
16A-04    GROUNDING SYSTEM

          Grounding will consist of copper clad steel rods connected with bare
          copper cable. The grounding system will be connected to the existing
          ground in the power plant. The interconnection conductors will be
          built into the main feeder cable. Building steel and all electrical
          equipment enclosures will be grounded.

16A-05    FEEDER CIRCUITS

          Feeders will supply 480/277 volt power from the main distributor to
          distribution panels. Main service will be adequately sized to serve
          the building's requirements as specified in these outline
          specifications. The main riser electrical feeder will be by a vertical
          plug-in type busway system. Includes transient voltage surge
          protection at the service entrance and branch circuit panel boards.

16A-06    TRANSFORMERS
          Dry-type K20 rated transformers will be provided for 120/208 volt
          panels.

16A-07    PANELBOARDS

          Panelboards will be 480/277 volt, 3-phase, 4-wire and 120/208 volt,
          3-phase, 4-wire with 200% neutrals with provisions for bolt in circuit
          breakers. Panelboards will be sized for the HVAC 6 watts per square
          foot and 2 watts per square foot for the 277 volt light fixtures and 6
          watts per square foot at for 120/208 volt power. Panelboards will be
          located in electrical closets on each floor.

16A-08    WIRING DEVICES, OUTLETS AND SWITCHES

          1.   Switches will be the quiet toggle type, NEMA standard.
          2.   Convenience outlets will be duplex grounding type, 20 amp rates,
               NEMA standard.
          3.   Device plates will be ivory-colored plastic.

16A-09    INDOOR LIGHTING
          Lighting will be fluorescent and/or incandescent for the base
          building. Lighting in tenant areas is not included.

16A-10    OUTDOOR LIGHTING

          Building lighting will be provided for security lighting and provide
          400 watt, high pressure sodium fixtures, energized at 277/480 volt
          with photocell control and time clock override. High pressure sodium
          fixtures will have integral ballasts. Fixtures will be pole-mounted in
          parking areas. Provide lighting at sidewalks for pedestrians. Lighting
          at the parking areas will be in accordance with the latest energy code
          requirements, but will provide a minimum of 0.5 foot candles at the
          remote parking areas.

                                       20
<PAGE>   81

                      DIVISION 16 - ELECTRICAL (Continued)

SECTION 16A - ELECTRICAL WORK (Continued)

16A-11    EMERGENCY LIGHTING AND POWER SYSTEM

          Provide emergency power for exit lights, emergency lighting and fire
          alarm system. Power source for emergency power shall be wet cell
          batteries located in the electrical rooms. Provide exit lights,
          emergency lights and fire alarm at all common areas as required by
          applicable codes. Exit lights, emergency lights and fire alarm
          distribution at tenant areas are not included.

16A-12    TELEPHONE EQUIPMENT

          Provide four (4) 4" sleeves at each telephone room (or as designated
          by the Tenant) through the second and third floor slabs.
          Interconnection and telephone equipment will be by the telephone
          company. Telephone interface will be the responsibility of the tenant
          and will be installed in the tenant's space.

16A-13    FIRE ALARM SYSTEM

          A local fully addressable fire alarm system with horn/light
          combinations, pull stations and annunciator panel will be provided for
          the base building. The main fire alarm panel and annunciator panel
          will be sized to accommodate the tenant area. Location of horn/lights,
          pull stations and annunciator panel shall be in accordance with
          applicable codes and the local fire department's requirements. Connect
          to the local fire department if available. Double shielded cable will
          be used.

                                       21
<PAGE>   82

                                  DIVISION 17

                                   EXCLUSIONS

1.   Power wiring for any special equipment or outlets other than those
     specified in these Outline Specifications.

2.   Special floor finishes, other than those previously mentioned.

3.   Special wall finishes, other than those previously mentioned.

4.   Special millwork items, other than those previously mentioned.

5.   Health Department or other regulatory agency requirements resulting from
     tenant's operations unknown to Gutierrez Construction Co., Inc.

6.   Furniture, furnishings, etc.

7.   Security, intercom or sound system.

8.   Vending machines or provisions for such.

9.   Kitchen equipment.

10.  Moveable partitions.

11.  Special exhaust systems.

12.  Underfloor duct systems.

13.  Drinking fountains, other than those specified.

14.  Drywall partitions, including demising walls and painting for tenant areas.

15.  Doors, frames and hardware for tenant areas.

16.  Vinyl base for tenant areas.

17.  Power distribution, lights, outlets, light switches, exit signs/lights, and
     emergency lights at tenant areas.

18.  Special modifications required for a day care center, if any.

19.  Sprinkler piping and heads at tenant areas.

20.  HVAC air terminal units, duct work, grilles and diffusers at tenant areas.

                                       22
<PAGE>   83

                                 "EXHIBIT C-1"

CERTIFICATE OF                     OWNER           [ ]
SUBSTANTIAL                        ARCHITECT       [ ]
COMPLETION                         CONTRACTOR      [ ]
                                   FIELD           [ ]
                                   OTHER
AIA DOCUMENT G704
--------------------------------------------------------------------------------
PROJECT:                                          ARCHITECT:
(name, address)
                                                  ARCHITECT'S PROJECT NUMBER:

TO (Owner)
                                                  CONTRACTOR:
                                                  CONTRACT FOR:

                                                  CONTRACT DATE:

DATE OF ISSUANCE:

PROJECT OR DESIGNATED AREA SHALL INCLUDE:

The Work performed under this Contract has been reviewed and found to be
substantially complete. The Date of Substantial Completion is hereby established
as
which is also the date of commencement of all warranties and guarantees
required by the Contract Documents.
--------------------------------------------------------------------------------
                  DEFINITION OF DATE OF SUBSTANTIAL COMPLETION

The Date of Substantial Completion of the Work or designated portion thereof is
the Date certified by the Architect when construction is sufficiently complete,
in accordance with the Contract Documents, so the Owner may occupy the Work or
designated portion thereof for the use for which it is intended.
--------------------------------------------------------------------------------

A list of items to be completed or corrected, prepared by the Contractor and
verified and amended by the Architect, is appended hereto. The failure to
include any items on such list does not alter the responsibility of the
Contractor to complete all Work in accordance with the Contract Documents.

----------------------------   ------------------------------   ----------------
ARCHITECT                      BY                               DATE

The Contractor will complete or correct the Work on the list of items appended
hereto within           days from the above Date of Substantial Completion.

----------------------------   ------------------------------   ----------------
CONTRACTOR                     BY                               DATE

The Owner accepts the Work or designated portion thereof as substantially
complete and will assume full possession thereof at             (time) on
            (date).

----------------------------   ------------------------------   ----------------
OWNER                          BY                               DATE

--------------------------------------------------------------------------------
The responsibilities of the Owner and the Contractor for maintenance, heat,
utilities and insurance shall be as follows: (NOTE -- Owner's and Contractor's
legal and insurance counsel should determine and review insurance requirements
and coverage)

<TABLE>
<S>                                                                                                                         <C>
------------------------------------------------------------------------------------------------------------------------------------
AIA DOCUMENT G704 - CERTIFICATE OF SUBSTANTIAL COMPLETION - APRIL 1970 EDITION - AIAR                                       ONE PAGE
(c) 1970 - THE AMERICAN INSTITUTE OF ARCHITECTS, 1735 NEW YORK AVE., NW, WASHINGTON, D.C. 20006
</TABLE>
<PAGE>   84
                                  EXHIBIT "C-2"

                         CERTIFICATE OF FINAL COMPLETION

Project:  Unisphere Solutions, Inc.                  Lease Date: _________, 2000

Location: Technology Park Drive                      Date:
        : Westford, Massachusetts

Owner:   Michelson Farm-Westford            ,        Trade:
         Technology Park X Limited Partnership

( )     All work has been completed in accordance with Article III of the Lease.

( )     All work has been completed in accordance with Article III of the Lease,
        except for that listed in attached schedule for which a credit has been
        taken.

Final Inspection was made _________________ in the presence of:

Remarks:

Owner must have completed or corrected all punch list items or accepted credit
for unsatisfactory or incomplete work and submitted all Close-out Documents as
listed on Close-out Documents - Record & Transmittal Form.

This is to certify that Unisphere Solutions, Inc. will not be held responsible
for any bills, liens, claims or demands in connection with the above noted
project. All workmanship and materials are hereby guaranteed in accordance with
stipulations in the Contract Documents and Lease on Certificate of Substantial
Completion.

By:________________________________         By:_________________________________

Title:______________________________        Title:______________________________

Date:______________________________         Date:_______________________________

NOTE:  See also definition of Substantial Completion in Article III of the
       Lease.
<PAGE>   85
                                   EXHIBIT "D"
                               LANDLORD'S SERVICES

I.       CLEANING

         A.       General

                  1.       All cleaning work will be performed between 8:00 AM
                           and midnight, Monday through Friday, unless otherwise
                           necessary for stripping, waxing, etc.

                  2.       Abnormal waste removal (e.g., computer installation
                           paper, bulk packaging, wood or cardboard crates,
                           refuse from cafeteria and laboratory operations,
                           etc.) shall be Tenant's responsibility.

         B.       Daily Operations (5 times per week)

                  1.       Tenant Areas

                           a.       Empty and clean all waste receptacles. Wash
                                    receptacles as necessary.

                           b.       Vacuum all rugs and carpeted areas.

                           c.       Empty, damp-wipe and dry all ashtrays.

                  2.       Lavatories

                           a.       Sweep and wash floors with disinfectant.

                           b.       Wash both sides of toilet seats with
                                    disinfectant.

                           c.       Wash all mirrors, basins, bowls, urinals.

                           d.       Spot-clean toilet partitions.

                           e.       Empty and disinfect sanitary napkin disposal
                                    receptacles.

                           f.       Refill toilet tissue, towel, soap and
                                    sanitary napkin dispensers.

                  3.       Public Areas

                           a.       Wipe down entrance doors and clean glass
                                    (interior and exterior).

                           b.       Vacuum elevator carpets and wipe down doors
                                    and walls.

         C.       Operations as Needed (but not less than every other day)

                  1.       Tenant and Public Areas

                           a.       Buff all resilient floor areas every other
                                    day.

                           b.       Clean water coolers.
<PAGE>   86
         D.       Weekly Operations

                  1.       Tenant Areas, Lavatories, Public Areas

                           a.       Hand dust and wipe clean all horizontal
                                    surfaces with treated cloths to include
                                    furniture, office equipment, window sills,
                                    door ledges, chair rails, baseboards,
                                    convector tops, etc. within normal reach.

                           b.       Remove finger marks from private entrance
                                    doors, light switches, and doorways.

                           c.       Sweep all stairways.

         E.       Monthly Operations

                  1.       Tenant and Public Areas

                           a.       Thoroughly vacuum seat cushions on chairs,
                                    sofas, etc.

                           b.       Vacuum and dust grillwork.

                  2.       Lavatories

                           a.       Wash down interior walls and toilet
                                    partitions.

         F.       As Required and Weather Permitting (but not less than three
                  times per year)

                  1.       Entire Building

                           a.       Clean inside of all windows.

                           b.       Clean outside of all windows.

         G.       Yearly

                  1.       Tenant and Public Areas

                           a.       Strip and wax all resilient tile floor
                                    areas.

II.      HEATING, VENTILATING AND AIR CONDITIONING

         1.       Heating, ventilation and air conditioning (HVAC) as required
                  to provide reasonably comfortable temperatures for normal
                  business day occupancy (except holidays), Monday through
                  Friday, from 8:00 AM to 6:00 PM and Saturday from 8:00 AM to
                  1:00 PM. Tenant shall be operating HVAC systems beyond the
                  hours specified above and any additional maintenance or
                  services associated with such overtime use shall be furnished
                  by Landlord provided that the additional costs thereof are
                  chargeable to Tenant pursuant to the provisions of Sections
                  4.2 and 5.1.2 Note: Cost of electricity to be paid directly by
                  Tenant to utility company.

                                       2
<PAGE>   87
         2.       Maintenance on any additional or special air conditioning
                  equipment and the associated operating cost will be at
                  Tenant's expense.

III.     WATER

         1.       Prior to the commencement of the Term hereunder, Landlord is
                  responsible for providing water up to, but not including,
                  Tenant's water meter, such that hot water for lavatory
                  purposes and cold water for drinking, lavatory and toilet
                  purposes are available. Thereafter, Tenant is responsible for
                  all water and sewer charges consumed in the leased premises,
                  as measured by Tenant's water meter.

         2.       The cost of the repair or replacement of a hot water heater
                  which supplies hot water exclusively in a sink in Tenant's
                  Premises will be the responsibility of Tenant.

IV.      ELEVATORS

         Elevators for the use of all tenants and the general public for access
         to and from all floors of the Building, programming of elevators
         (including, but not limited to, service elevators), shall be as
         Landlord from time to time reasonably determines best for the Building
         as a whole, Landlord hereby agreeing that Tenant may provide input in
         connection therewith.

V.       RELAMPING OF LIGHT FIXTURES

         Tenant will reimburse Landlord for relamping, ballasts and starters
         within the Premises.

VI.      CAFETERIA, VENDING AND PLUMBING INSTALLATIONS; LABORATORY

         1.       Any space to be used primarily for lunchroom or cafeteria
                  operation shall be Tenant's responsibility to keep clean and
                  sanitary, unless otherwise mutually agreed upon in writing by
                  Landlord and Tenant. Cafeteria, vending machines or
                  refreshment service installations by Tenant must be approved
                  by Landlord in writing, Landlord hereby acknowledging and
                  agreeing that it shall approve a cafeteria in connection with
                  the Tenant's Plans. All maintenance, repairs and additional
                  cleaning necessitated by such installations shall be at
                  Tenant's expense.

         2.       Tenant is responsible for the maintenance and repair of
                  plumbing fixtures and related equipment installed in the
                  Premises for its exclusive use (such as in coffee room,
                  cafeteria, laboratory, or employee exercise area, if
                  applicable), and all of such other fixtures described as
                  Tenant's Property in Section 6.1.13.

         3.       Any space to be used primarily for laboratory operations
                  (currently estimated at 15,000 square feet) shall be Tenant's
                  responsibility to keep clean and neat, unless otherwise
                  mutually agreed upon in writing by Landlord and Tenant.

                                       3
<PAGE>   88
VII.     ELECTRICITY

         1.       Tenant shall pay for all electricity and gas consumed in the
                  Premises directly to the respective utility providers.

         2.       Tenant's use of electrical service in the Premises shall not
                  at any time exceed the capacity of any of the electrical
                  conductors or other equipment in or otherwise serving the
                  Premises or the Building standard, as hereinafter provided. To
                  ensure that such capacity is not exceeded and to avert
                  possible adverse effects upon the Building's electrical
                  system, Tenant shall not, without at least ten (10) days prior
                  written notice to and consent of Landlord in each instance,
                  connect to the Building electric distribution system any
                  fixtures, appliances or equipment which operates on a voltage
                  in excess of 120 volts nominal, or which requires a single
                  (dedicated) circuit, or make any alteration or addition to the
                  electric system of the Premises. In the event Tenant shall use
                  (or request that it be allowed to use) electrical service in
                  excess of that deemed by Landlord to be standard for the
                  Building, Landlord may refuse to provide such excess usage or
                  refuse to consent to such usage or may consent upon such
                  conditions as Landlord reasonably elects (including but not
                  limited to the installation of utility service upgrades,
                  submeters, air handlers or cooling units), and all such
                  additional usage (except to the extent prohibited by law),
                  installation and maintenance thereof shall be paid for by
                  Tenant, as additional rent, upon Landlord's demand.

         3.       It is understood that the electrical service to the Premises
                  may be furnished by one or more suppliers of electricity and
                  that the cost of electricity may be billed as a single charge
                  or divided into and billed in a variety of categories such as
                  distribution charges, transmission charges, generation
                  charges, public good charges and other similar categories and
                  may also include a reasonable fee, commission or other charge
                  by a broker, aggregator or other intermediary for obtaining or
                  arranging the supply of electricity. Landlord shall, upon
                  Tenant's prior approval (not to be unreasonably withheld or
                  delayed) so long as Tenant remains the sole tenant of the
                  Building, have the right to select the supplier of electricity
                  to the Building, Premises and Lot, and, as Tenant's agent, to
                  designate the same to a local utility, to aggregate the supply
                  of electricity for the Building, Premises and Lot with other
                  buildings, to purchase electricity for the Building, Premises
                  and Lot through a broker, aggregator or other intermediary
                  and/or buyers group or other group and to change the supplier
                  of electricity and/or manner of purchasing electricity from
                  time to time.

                  If Landlord undertakes activities for the purpose of reducing
                  Landlord's or Tenant's operating costs (such as negotiating an
                  agreement with a utility or another energy supplier or
                  engaging an energy consultant or undertaking conservation or
                  other energy efficient measures that may require capital
                  expenditures), Tenant shall pay its proportionate share of all
                  costs and expenses associated with such actions (including but
                  not limited to brokers' commissions, legal fees and capital
                  expenditures), as additional rent, as and when payment is made
                  by Landlord, so long as Tenant's approval has been obtained by
                  Landlord in advance, which such approval shall not be
                  unreasonably

                                       4
<PAGE>   89
                  withheld or delayed by Tenant and which such approval of
                  Tenant shall only be required so long as Tenant remains the
                  sole tenant of the Building.

         4.       Utility lines and other facilities that supply the Premises,
                  whenever installed, may be the subject of a requirement that
                  the owner of the Premises make payments for the lines or other
                  facilities upon the occurrence of certain events, if, for
                  example, a tenant utilizing such facilities discontinues
                  purchasing energy from the provider of the facilities,
                  Landlord may be required to enter into agreements that would
                  obligate it to make such payments in the future. Landlord
                  agrees to notify the Tenant of any such agreements, any
                  amendments, modifications, replacements or substitutions
                  thereto, Landlord hereby acknowledging that there are no such
                  agreements currently in force or effect. If such payments are
                  required, whether based on contract or tariff, from Landlord
                  with respect to such facilities that are utilized by the
                  Tenant, the Landlord shall so inform Tenant in writing, and
                  the Tenant thereby agrees that it shall reimburse the Landlord
                  for its proportionate share of all such payments as additional
                  rent, when and as made by the Landlord, with no profit to
                  Landlord.

         5.       As used in this Section VII, the term "supplier(s) of
                  electricity" shall mean one or more companies (including but
                  not limited to an electric utility, generator, independent or
                  non-regulated company or intermediary or broker or group) that
                  provides electricity to the Premises or to the Landlord to be
                  provided to the Premises, as the case may be.

VIII.             SNOW REMOVAL AND LANDSCAPING

                  As may be necessary and consistent with the other lots in the
                  Park to provide landscaping services and snow removal on the
                  Lot.

                                       5
<PAGE>   90
                                   EXHIBIT "E"
                              RULES AND REGULATIONS

1.       No curtains, blinds, shades, screens, or signs other than those
         furnished by Landlord shall be attached to, hung in, or used in
         connection with any window or door of the Premises without the prior
         written consent of the Landlord. All interior Tenant signage is at
         Tenant's expense and must be installed or affixed by a contractor first
         approved by Landlord acting reasonably and without delay. The style,
         size and color of any interior signage visible from the exterior of the
         Premises must also be reasonably acceptable to Landlord.

2.       As well as any security (door access) system provided and installed by
         Tenant, as reasonably approved by Landlord, Tenant shall be allowed to
         place additional locks or bolts upon doors and windows within the
         Premises. Tenant recognizes that these additional locks and bolts could
         prove to be a hindrance to Landlord providing building services such as
         cleaning and maintenance. Tenant must, upon the termination of its
         tenancy and provide Landlord all Building access cards and keys either
         furnished to or otherwise procured by Tenant; and in the event of the
         loss of any keys so furnished, Tenant shall pay to Landlord the
         reasonable cost thereof.

3.       Canvassing, soliciting and peddling in the Building are prohibited, and
         Tenant shall cooperate to prevent the same.

4.       Tenant shall comply with all reasonably necessary security measures
         from time to time established by Landlord for the Park.

5.       Tenant agrees that there shall be no smoking allowed anywhere in the
         Building.

6.       Tenant shall comply with the Park Covenants attached hereto as Exhibit
         "I", provided that such compliance is within Tenant's control, Landlord
         hereby acknowledging and agreeing, as set forth in Section 10.18, that
         Landlord's construction of the Landlord's Work and Tenant's Work shall
         be in compliance therewith.
<PAGE>   91
                                   EXHIBIT "F"
                                OPTION TO EXTEND

         The Tenant has the option to extend this Lease for two (2) successive
five (5) year terms ("Extended Terms", and separately the "First Extended Term"
and the "Second Extended Term"), the exercise of each of which shall
automatically extend the term of this Lease without the necessity of additional
documentation. So long as there does not exist any Event of Default hereunder at
such time, and except as otherwise set forth in Article VII of this Lease, the
option to extend shall be deemed to have been exercised as to the First Extended
Term by Tenant's notification to Landlord that it elects to exercise its first
option to extend at least twelve (12) months but not more than eighteen (18)
months prior to the end of the initial Term hereunder, and as to the Second
Extended Term by Tenant's notification to Landlord that it elects to exercise
its second option to extend at least twelve (12) months but not more than
eighteen (18) months prior to the end of the First Extended Term. Each Extended
Term shall be upon the same terms and conditions as are set forth in this Lease,
including, without limitation, the Tenant's obligations to pay Operating Cost
Escalation set forth in Section 4.2, except that (i) there shall be no
additional option to extend after the termination of the Second Extended Term or
the failure to exercise the first option, whichever shall first occur, (ii) the
annual Fixed Rent for the First Extended Term shall be equal to the Market Rent
(as defined in and determined in accordance with Exhibit P), and (iii) the
annual Fixed Rent for the Second Extended Term shall be equal to the Market Rent
(as defined and determined in accordance with Exhibit P). In no event, however,
shall the annual Fixed Rent and additional rent for the First Extended Term and
for the Second Extended Term be less than the rent then in effect as of the last
day immediately preceding the First Extended Term or Second Extended Term, as
applicable.
<PAGE>   92
                                   EXHIBIT "G"

                              ESTOPPEL CERTIFICATE

        THIS CERTIFICATE is made to ___________________________ (the "Bank")
with respect to a lease dated _________________ execute by and between
________________________ (the "Landlord") and the undersigned (as "Tenant"),
covering a building (a portion of a building) located in _____________ (the
"Lease"), as amended by (list all amendments):

        The undersigned has been advised that the Bank is about to enter into a
transaction whereby the Bank is making a loan secured by the aforesaid real
estate and the Lease to the undersigned, and under which the Bank may acquire an
ownership interest in such real estate. In connection with this transaction, the
entire interest of the Landlord under the Lease to the undersigned will be
assigned to the Bank. The undersigned acknowledges that the Bank is and will be
relying upon the truth, accuracy and completeness of this letter in proceeding
with the transaction described above.

        The undersigned, for the benefit of the bank, their successors and
assigns, hereby certifies, represents, warrants, agrees and acknowledges that:

        1. The Lease is in full force and effect in accordance with its terms
without modification or amendment except as noted above and the undersigned is
the holder of the Tenant's interest under the Lease.

        2. The undersigned is in possession of all of the Premises described in
the Lease under and pursuant to the Lease and is doing business thereon; and the
premises are completed as required by the Lease.

        3. The undersigned has no claims or offsets with respect to any of its
obligations as Tenant under the Lease, and neither the undersigned nor the
Landlord is claimed to be in default under the Lease.

        4. The undersigned has not paid any rental or installments thereof in
advance of the due date as set forth in the Lease.

        5. The undersigned has no notice of prior assignment, hypothecation or
pledge of rents of the Lease or the Landlord's interest thereunder or of the
Tenant's interest thereunder.

        6. The term of the Lease has commenced and is presently scheduled to
expire on __________, ____. If there are any rights of extension or renewal
under the terms of the Lease, the same have not, as of the date of this letter,
been exercised.

        7. Until such time as the Bank shall become the Landlord, if the
undersigned should assert a claim that the Landlord has failed to perform an
obligation to the undersigned under the terms of the Lease or otherwise, notice
thereof shall promptly be furnished to the Bank; and the undersigned agrees
<PAGE>   93
that the undersigned will not exercise any rights which the undersigned might
otherwise have on account of any such failure until notice thereof has been
given to the Bank, and the Bank has had the same opportunity to cure any such
failure as the Landlord may have under the terms of the Lease.

        8. Each of the statements set forth in Paragraphs 1 through 7 are true,
accurate and complete except as follows (state specifically any exception):

DATED

ATTEST:

                                                  By:

                                                  Its:

                                       2
<PAGE>   94
                                   EXHIBIT "H"

                              INTENTIONALLY DELETED
<PAGE>   95
                                   EXHIBIT "I"

                                 PARK COVENANTS

         Landlord agrees with Tenant to enforce, or cause to be enforced, these
Park Covenants with all due diligence to preserve the quality and appearance of
the Park.

         The Lot is approximately ________________ (____) acres and is located
in an approximately ninety (90) acre office/research and development park shown
on the Plan of the Park attached hereto as part of Exhibit A and more
particularly described therein and elsewhere in this Lease, as the same,
including without limitation the Common Areas of the Park, may be amended by
Landlord from time to time in accordance with and subject to the provisions of
Section 2.1 of this Lease.

         All lots of land comprising the Park (which lots, including without
limitations the Lot, are individually called the "Parcel" and collectively the
"Parcels") are subject to the following restrictions which shall bind Michelson
Farm-Westford Technology Park Trust (collectively "Grantor") as original owner
of the Park and its successors in title.

         A. All parcels shall have facilities for parking, loading and unloading
sufficient to serve any uses of the Parcels without using adjacent streets for
such purpose. On-street parking shall be prohibited. All parking, trucking and
vehicular maneuvering areas for a Parcel shall be contained within such Parcel.

         B. No exterior loading platforms shall be visible from any primary way
or proposed primary way serving the Park. Screening and planting may be used for
this purpose.

         C. No open or outside storage shall be done on any Parcel, other than
normal and customary trash compactors and containers on locations to be
reasonably approved by Landlord in advance.

         D. Signs shall conform to the sign ordinances of the Town of Westford.
Any variance from such ordinance granted by the Town of Westford must also be
approved by Grantor in the manner provided below in Section I.

         E. No condition or use of any Parcel will be permitted which is
objectionable by reason of noise, odor, vibration, smoke, radiation, the
hazardous nature of the use, or the violation of environmental laws or
regulations adopted by the Town of Westford, the Commonwealth of Massachusetts,
the Federal Government or any Court.

         F. All utilities serving a Parcel shall be placed underground, unless
prohibited by the utility company. Any exterior lighting on a Parcel shall
either be indirect or of such controlled focus and intensity as not to disturb
street traffic or the occupancy of any adjacent Parcel.

         G. The exterior appearance of any buildings in the Park, including
landscaping thereon, shall be kept neat and orderly and free from litter.

<PAGE>   96
         H. No building, exterior sign, fence, wall, exterior lighting or other
structure shall be erected or allowed to maintain on any portion of the Park or
exterior structural alteration or addition made, except pursuant to plans
approved in writing by Grantor as to landscaping, parking and architectural
conformity with existing buildings in the Park.

         I. The Grantor may from time to time by written instrument in
recordable form grant variance from any one or more of these restrictions
(except restriction H for which variances may not be granted) where the Grantor
reasonably determines that the variance can be granted without substantial
detriment to the intent and purpose of the restrictions and without substantial
detriment to the Land, and portions of the Park theretofore built upon.

         J. Written approval by the Grantor as to any buildings, signs,
structures, alterations, additions and landscaping approved by Grantor in good
faith shall be conclusive evidence of compliance with these restrictions. The
Grantor agrees to furnish to any grantee such written instruments in recordable
form as may reasonably be requested by the grantee as evidence of such
compliance.

         K. The term "Grantor", as herein used, shall mean Arthur J. Gutierrez
and John A. Cataldo, Class A Trustees, and Howard Stock and Marc D. Levy, Class
B Trustees, all as Trustees of Michelson Farm-Westford Technology Park Trust,
u/d/t dated October 1, 1984 and recorded with the Middlesex North District
Registry of Deeds in Book 2863, Page 235, and any of its successors in title to
whom the Grantor has expressly granted of record the rights to enforce these
restrictions.

                                       2
<PAGE>   97
                                   EXHIBIT "J"

                            LESSEE'S LEASE STATEMENT
                                       AND
             SUBORDINATION, NON-DISTURBANCE AND ATTORNMENT AGREEMENT

         THIS AGREEMENT is made and entered into as this ____ day of
___________, 2000, by and among ______________________________, a
______________________________ (hereinafter called the ("Lender"),
________________________ (hereinafter called the "Tenant") and
______________________________ (hereinafter called the "Landlord").

                              W I T N E S S E T H

         WHEREAS, Landlord owns certain real property commonly known as
_______________, ________________________ and located in _____________ County,
Massachusetts, and more particularly described in Exhibit "A" attached hereto
and made a part hereof (said property being hereinafter called the "Property");
and

         WHEREAS, Landlord and Tenant made and entered into that certain Lease,
dated as of the ___ day of ____________, 2000, with respect to certain premises
located on the Property constituting the Premises therein described, as the same
may be expanded pursuant to Exhibit "R" of the Lease (said Lease being
hereinafter called the "Lease" and said premises being hereinafter called the
"Leased Premises"), notice of which was recorded in the Middlesex _________
Registry of Deeds on _________________, 2000 as Instrument No. _______; and

         WHEREAS, Landlord has entered into and delivered that certain Mortgage
and Security Agreement in favor of Lender recorded in the Middlesex _________
Registry of Deeds on _______________, 2000 as Instrument No. ______ prior to the
recording of this Agreement (said Mortgage and Security Agreement being
hereinafter called the "Security Deed"), conveying the Property to secure the
payment of the indebtedness described in the Security Deed; and

         WHEREAS, on or about the date hereof, Landlord has entered into and
delivered that certain Assignment of Leases and Rents in favor of Lender
recorded in the Middlesex _______ Registry of Deeds on _______________, _______
as Instrument No. _________ prior to the recording of this Agreement (said
Assignment of Leases and Rents being hereinafter called the "Assignment of
Leases"), assigning all of Landlord's right, title and interest as lessor under
the Lease to further secure the indebtedness described in the Security Deed; and

         WHEREAS, the Lender represents that it is the sole holder of the
Security Deed and the Promissory Note and other loan documents secured thereby;
and

         WHEREAS, the parties hereto desire to enter into this Non-Disturbance,
Attornment and Subordination Agreement;
<PAGE>   98
         NOW, THEREFORE, for and in consideration of the mutual covenants
hereinafter set forth and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Lender, Tenant and Landlord hereby
covenant and agree as follows:

         1. ESTOPPEL - Tenant hereby certifies to Lender that, as of the date of
this Agreement: (i) the Lease, as described above, is the true, correct and
complete Lease and has not been modified or amended and constitutes the entire
agreement between Landlord and Tenant, (ii) to the best of Tenant's knowledge,
without inquiry, there are no defaults of Landlord under the Lease and there are
no existing circumstances which with the passage of time, or giving of notice,
or both, would give rise to a default under the Lease and/or allow Tenant to
terminate the Lease, and (iii) Tenant is satisfied with all of the work done by
and required of Landlord to date, such work has been done in accordance with
plans and specifications approved by Tenant, and as of the date hereof Tenant is
not aware of any defect in the work or has not rejected any of the work done by
Landlord on the Leased Premises. If this Agreement is being delivered prior to
completion of all of Landlord's Work (as such term is defined in the Lease) on
the Leased Premises, Tenant agrees that, promptly after request of the Lender
therefor, it will provide an estoppel certificate to Lender following completion
of such work indicating whether Tenant has accepted the work and begun payment
of rent.

         2. NON-DISTURBANCE - Lender agrees that if Lender comes into possession
of or acquires title to all or any part of the Leased Premises or the Lot (as
defined in the Lease) as a result of foreclosure or other enforcement of the
Security Deed or the Assignment of Leases, or both, then so long as no default
under the Lease by Tenant exists and continues beyond the expiration of all
applicable cure periods (after notice, if any, required by the Lease) as would
entitle the lessor under the Lease to terminate the Lease or would cause,
without any further action on the part of such lessor, the termination of the
Lease or would entitle the lessor under the Lease to exercise any other remedy
available to it on account of Tenant defaults under the Lease, the Lease shall
not be terminated, nor shall Tenant's use, possession or enjoyment of the Leased
Premises and appurtenant rights and interests or rights under the Lease be
interfered with. Following a foreclosure or other action or proceeding in the
nature of foreclosure instituted under or in connection with the Security Deed
or the Assignment of Leases, or the acquisition of title to the Leased Premises,
the person or entity acquiring the interest of the lessor under the Lease as a
result of any such action or proceeding or deed in lieu of any such action or
proceeding (hereinafter called the "Purchaser") or Lender if Lender takes
possession of the Property shall have all rights and obligations of Landlord
under the Lease, except as expressly otherwise set forth herein, provided,
however, that neither the Purchaser nor the Lender shall be (a) liable for any
act or omission of any prior lessor under the Lease provided that nothing herein
shall relieve such Purchaser or Lender from curing any continuing defaults of
lessor after receipt of requisite notices from Tenant, all in accordance with
the Lease; or (b) liable for the return of any security deposit which lessee
under the Lease has paid under the Lease unless such security deposit is
received by Lender; or (c) subject to any offsets or defenses which the lessee
under the Lease might have against any prior lessor under the Lease unless
Lender has received prior written notice of the offset or defense and
opportunity to cure the same in accordance with Section 7 below; or (d) bound by
any base rent, or any other payments which the lessee under the Lease might have
paid for more than the current month to any prior lessor under the Lease; or (e)
bound by any amendment or modification of the Lease made without Lender's prior
written consent (Lender hereby agreeing not to unreasonably withhold or delay
its consent); or (f) bound by any assignment or sublease of the lessee's
interest in the Lease made without obtaining Lender's prior written consent

                                       2
<PAGE>   99
(such consent not to be unreasonably withheld or delayed), except where the
consent of the Landlord is not required pursuant to the provisions of Section
6.1.6 of the Lease (in which event no consent of Lender shall be required); or
(g) personally liable for any default under the Lease or any covenant or
obligation on its part to be performed thereunder as lessor, it being
acknowledged that Tenant's sole remedy in the event of such default shall be to
proceed against Purchaser's or Lender's interest in the Property and the rents,
or other proceeds arising therefrom.

         In the event that Lender acquires title to or possession of all or any
part of the Leased Premises, whether pursuant to a foreclosure proceeding or
otherwise, then within thirty (30) days thereafter, the Lender may elect to
deliver a written notice to the Tenant stating that either (i) the Lender
intends to perform the construction obligations of the Landlord set forth in
Article III of the Lease (the "Construction Obligations"), or (ii) the Lender
does not intend to perform the Construction Obligations. A notice delivered by
the Lender pursuant to clause (i) is referred to herein as an "Opt-In
Construction Notice" and a notice delivered by the Lender pursuant to clause
(ii) is referred to herein as an "Opt-Out Construction Notice".

         In the event that the Lender does not deliver either an Opt-Out
construction Notice or an Opt-In Construction Notice to the Tenant within said
thirty (30) days after acquisition of title or possession, then Tenant may elect
to deliver a written request (a "Construction Confirmation Request") to the
Lender, requesting that Lender deliver either an Opt-Out Construction Notice or
an Opt-In Construction Notice.

         If either (a) Lender delivers an Opt-Out Construction Notice to Tenant
as aforesaid, or (b) Lender does not deliver an Opt-In Construction Notice to
Tenant by not later than thirty (30) days after receipt of Tenant's Construction
Confirmation Request, then Lender shall not be obligated to perform the
Construction Obligations in accordance with the terms and provisions the Lease.
If Lender delivers an Opt-In Construction Notice as aforesaid, then Lender shall
be obligated to perform the Construction Obligations in accordance with the
terms and provisions of the Lease. If Lender timely delivers an Opt-Out
Construction Notice to Tenant by not later than thirty (30) days after receipt
of Tenant's Construction Confirmation Request as aforesaid, or Lender does not
deliver an Opt-In Construction Notice to Tenant by not later than thirty (30)
days of its receipt of Tenant's Construction Confirmation Request, then (a)
Lender shall have no obligation to perform the Construction Obligations, and (b)
Tenant may elect to terminate the Lease by providing written notice of such
election to Lender. If Tenant elects to terminate the Lease, the Lease shall be
terminated effective as of the date specified in Tenant's notice. Thereafter the
Lease shall be null and void and of no further force or effect, and neither the
Tenant nor the Lender shall have any further liabilities or obligations
thereunder.

         If (a) Lender sells, conveys, assigns, pledges or transfers its
interest in the Loan, or (b) Lender sells the Leased Premises, or any part
thereof, at a foreclosure sale, or (c) if Lender acquires title to the Leased
Premises and subsequently conveys the Leased Premises, then, in any such event,
concurrently with such transaction, Lender shall transfer, assign and convey all
right, title and interest of the Lender in and to the Security Deposit then held
by it, if applicable, to such purchaser, assignee, or transferee.
Notwithstanding anything to the contrary contained in this Section, if Lender so
transfers, assigns or conveys all right, title and interest of the Lender in and
to the Security Deposit, if applicable, as aforesaid, then Lender shall have no
liability for the return of the Security Deposit.

                                       3
<PAGE>   100
         3. ATTORNMENT - Unless the Lease is terminated in accordance with
Paragraph 2 or in accordance with the terms of the Lease, if the interests of
the lessor under the Lease shall be transferred by reason of the exercise of the
power of sale contained in the Security Deed (if applicable), or by any
foreclosure or other proceeding for enforcement of the Security Deed, or by deed
in lieu of foreclosure or such other proceeding, or if Lender takes possession
of the Property pursuant to any provisions of the Security Deed, Tenant shall be
bound to the Purchaser or Lender, as the case may be, under all of the terms,
covenants and conditions of the Lease for the balance of the term thereof and
any extensions or renewals thereof which may be effected in accordance with any
option therefor in the Leases with the same force and effect as if the Purchaser
or Lender were the lessor under the Lease, and Tenant, as lessee under the
Lease, does hereby agree to attorn to the Purchaser and Lender if it takes
possession of the Property, as its lessor under the Lease. Such attornment shall
be effective and self-operative without the execution of any further instruments
upon succession by Purchaser to the interest of the lessor under the Lease or
the taking of possession of the Property by Lender. Nevertheless, Tenant shall,
from time to time, execute and deliver such instruments evidencing such
attornment as Purchaser or Lender may reasonably require. The respective rights
and obligations of Purchaser, Lender and of the lessee under the Lease upon such
attornment, to the extent of the then remaining balance of the term of the Lease
and any such extensions and renewals, shall be and are the same as now set forth
in the Lease, except as otherwise expressly provided in Paragraph 2 above.

         4. SUBORDINATION - Subject to the provisions of this Agreement, Tenant
hereby subordinates all of its rights, title and interest as lessee under the
Lease to the right, title and interest of Lender under the Security Deed, and
Tenant further agrees that the Lease now is and shall at all times continue to
be subject and subordinate in each and every respect to the Security Deed and to
any and all increases, renewals, modifications, extensions, substitutions,
replacements and/or consolidations of the Security Deed and to all sums secured
thereby with the same force and effect as if the Security Deed had been
executed, delivered and recorded prior to the execution and delivery of the
Lease.

         5. OTHER CONDITIONS - Notwithstanding anything to the contrary
contained in this Agreement or in the Lease, Lender, Tenant and Landlord agree:
(a) that to the extent required by the Lease, and provided that (i) Tenant has
not defaulted in the payment of rent or other charges under the Lease, (ii)
Landlord has not defaulted in the payment of debt service or other payments
under the loan documents and (iii) neither Landlord or Tenant has filed a
voluntary petition in bankruptcy under Title 11 of the United States Code or had
an order for relief issued against it and not dismissed within thirty (30) days
of issuance or has filed any petition or answer seeking or acquiescing in any
reorganization, arrangement, composition, readjustment, liquidation, dissolution
or similar relief for itself under any present or future federal, state or other
law or regulation relating to bankruptcy, insolvency or other relief of debtors
or consented or acquiesced in the appointment of any custodian, trustee,
receiver, conservator or liquidator for it or all or any substantial part of its
property or made an assignment for the benefit of creditors, then in the event
of an insured casualty to the Leased Premises, and if Landlord satisfies the
conditions provided for hereafter, Lender shall hold the balance of any casualty
proceeds after proof and adjustment and shall use such funds for the following
purposes: (x) to pay costs and obligations secured by the Security Deed (the
"Secured Obligations") as such become due during the course of reconstruction or
repair of the Leased Premises (y) to reimburse Landlord, in accordance with the
terms and conditions set forth below, for the costs of reconstruction or repair
of the Leased Premises,

                                       4
<PAGE>   101
and (z) upon completion of such reconstruction or repair, to apply any excess to
the payment of the Secured Obligations. Such funds shall be made available as
provided above upon the Landlord's prior satisfaction of such conditions as the
Lender may reasonably establish with respect thereto (each of which must be
complied with in a manner reasonably satisfactory to the Lender, with all
documents, instruments, agreements, or evidence to be in form and substance
satisfactory to the Lender), including without limitation, the following
(hereinafter referred to as the "Funding Requirements"):

                  (i) delivery of estoppel certificate(s) or other satisfactory
                  evidence that the Lease remains in full force and effect and
                  will remain in full force and effect after such repair and
                  restoration, without any right of termination or cancellation
                  during the projected course of said repair or restoration;

                  (ii) delivery of plans and specifications, construction
                  budget, construction contract, and construction schedule for
                  such repair and restoration, satisfactory to Lender;

                  (iii) delivery of evidence of compliance with all applicable
                  state, federal, and local laws, ordinances and regulations
                  relating to such repair and restoration, and the issuance of
                  all required permits, licenses and approvals relative thereto;

                  (iv) delivery of evidence of the availability of any funds
                  necessary to complete such repairs and restoration in excess
                  of such proceeds, which funds, at the request of the Lender,
                  shall be deposited with the Lender to be disbursed with such
                  proceeds;

                  (v) builder's all risk insurance;

                  (vi) rent loss insurance sufficient to pay all operating costs
                  and debt service confirmed by the insurer to be available for
                  the period of repair and restoration;

                  (vi) evidence that the insurer under such policies of fire or
                  other casualty insurance does not assert any defense to
                  payment under such policies against Lender, Landlord or any
                  tenant of the Leased Premises;

                  (vii) execution of any documentation deemed reasonably
                  necessary by the Lender to provide for the disbursement of
                  such funds in a manner typical to a construction loan;

                  (viii) delivery of evidence that the repair or restoration can
                  be completed prior to the then applicable maturity date of the
                  note;

                  (ix) Landlord delivers to Lender a written undertaking to
                  expeditiously commence and to satisfactorily complete with due
                  diligence the necessary restoration; and

                  (x) compliance of such other reasonable non-financial terms
                  and conditions customary for construction loans of the size
                  and scope involved with such repairs and restoration.

                                       5
<PAGE>   102
         6. ASSIGNMENT OF LEASES - Tenant hereby acknowledges that all of
Landlord's right, title and interest as lessor under the Lease is being duly
assigned to Lender pursuant to the terms of the Assignment of Leases, and that
pursuant to the terms thereof all rental payments under the Lease shall continue
to be paid to Landlord in accordance with the terms of the Lease unless and
until Tenant is otherwise notified in writing by Lender. Upon receipt of any
such written notice from Lender, Tenant covenants and agrees to make payment of
all rental payments then due or to become due under the Lease directly to Lender
or to Lender's agent designated in such notice and to continue to do so until
otherwise notified in writing by Lender. Landlord hereby irrevocably directs and
authorizes Tenant to make rental payments directly to Lender following receipt
of such notice and covenants and agrees that Tenant shall have the right to rely
on such notice without any obligation to inquire as to whether any default
exists under the Security Deed or the Assignment of Leases or the indebtedness
secured thereby, and notwithstanding any notice of claim of Landlord to the
contrary, that Landlord shall have no right or claim against Tenant for or by
reason of any rental payments made by Tenant to Lender following receipt of such
notice. Except as otherwise specifically set forth in the Lease, Tenant further
acknowledges and agrees: (a) that under the provisions of the Assignment of
Leases, the Lease cannot be terminated (nor can Landlord accept any surrender of
the Lease) or modified in any of its terms, or consent be given to the waiver or
release of Tenant from the performance or observance of any obligation under the
Lease without the prior written consent of Lender, and without such consent, no
rent may be collected or accepted by Landlord more than one month in advance;
and (b) that the interest of Landlord as lessor under the Lease has been
assigned to Lender for the purposes specified in the Assignment of Leases, and
Lender assumes no duty, liability or obligation under the Lease, except only
under the circumstances, terms and conditions specifically set forth in the
Assignment of Leases or this Agreement.

         7. NOTICE OF DEFAULT BY LESSOR - Tenant, as lessee under the Lease,
hereby covenants and agrees to give Lender written notice properly specifying
wherein the lessor under the Lease has failed to perform any of the covenants or
obligations of the lessor under the Lease simultaneously with the giving of any
notice of such default to the lessor under the provisions of the Lease. Tenant
agrees that Lender shall have the right, but not the obligation, within thirty
(30) days after receipt by Lender of such notice (or, with respect to
non-monetary defaults only, within such additional time as is reasonably
required to correct any such default) to correct or remedy, or cause to be
corrected or remedied, each such default before the lessee under the Lease may
take any action under the Lease by reason of such default; provided however, in
no event shall such time extend for more than sixty (60) days after Tenant
provides such notice to Lender, except if Lender has commenced to cure any such
non-monetary default under the Lease (which shall in no event include
foreclosure or exercise of other remedies available under the Security Deed)
within thirty (30) days after such written notice to Lender and is diligently
proceeding to cure such default and such non-monetary default cannot be cured
within sixty (60) days despite such diligent efforts to cure on the part of
Lender, in which event such time period may be extended for an additional period
of not more than thirty (30) days. Such notices to Lender shall be delivered in
duplicate in writing by registered or certified mail, return receipt requested,
or by depositing the same with an overnight commercial courier (such as Federal
Express) or by hand delivery to:

                                       6
<PAGE>   103
                                    __________________________
                                    __________________________
                                    __________________________
                                    Attention: _______________

or to such other address as the Lender shall have designated to Tenant by giving
written notice to Tenant, prior to the Term Commencement Date at:

                                    __________________________
                                    __________________________
                                    __________________________
                                    Attention: _______________

after the Term Commencement Date at:

                                    __________________________
                                    __________________________
                                    __________________________
                                    Attention: _______________

or to such other address as may be designated by written notice from Tenant to
Lender.

         8. NO FURTHER SUBORDINATION - Except as expressly provided to the
contrary in Paragraph 4 hereof, Landlord and Tenant covenant and agree with
Lender that there shall be no further subordination of the interest of lessee
under the Lease to any lender or to any other party without first obtaining the
prior written consent of Lender. Any attempt to effect a further subordination
of lessee's interest under the Lease without first obtaining the first written
consent of Lender shall be null and void.

         9.  CONSENT - Lender hereby consents to the Lease.

         10. TRADE FIXTURES OR EQUIPMENT - The lien of the Security Deed does
not encumber any trade fixtures or equipment used by Tenant in its business on
the Property.

         11. AS TO LANDLORD AND TENANT - As between Landlord and Tenant,
Landlord and Tenant covenant and agree that nothing herein contained nor
anything done pursuant to the provisions hereof shall be deemed or construed to
modify the Lease.

         12. AS TO LANDLORD AND LENDER - As between Landlord and Lender,
Landlord and Lender covenant and agree that nothing herein contained nor
anything done pursuant to the provisions thereof shall be deemed or construed to
modify the Security Deed or the Assignment of Leases.

                                       7
<PAGE>   104

         13. TITLE OF PARAGRAPHS - The titles of the paragraphs of this
agreement are for convenience and reference only, and the words contained
therein shall in no way be held to explain, modify, amplify or aid in the
interpretation, construction or meaning of the provisions of this agreement.

         14. GOVERNING LAW - This agreement shall be governed by and construed
in accordance with the laws of the Commonwealth of Massachusetts.

         15. PROVISIONS BINDING - The terms and provisions hereof shall be
binding upon and shall inure to the benefit of the heirs, executors,
administrators, successors and permitted assigns, respectively, of Lender,
Tenant and Landlord. The reference contained to successors and assigns of Tenant
is not intended to constitute and does not constitute a consent by Landlord or
Lender to an assignment by Tenant where such consent is required under the
Lease, but has reference only to those instances in which the lessor under the
Lease and Lender shall have given written consent to a particular assignment by
Tenant thereunder where such consent is required under the Lease.

         In the event of any transfer of the Security Deed or the note secured
thereby, the Lender shall transfer and deliver to the transferee any security
deposit under the Lease held by Lender or its agent, and provided the transferee
assumes the obligations of Lender hereunder or otherwise recognizes the
provisions hereof by written instrument, Lender shall thereupon become freed and
relieved of all covenants and obligations of the Lender hereunder, except with
respect to any breaches of this Agreement as shall have theretofore occurred.

         16. COUNTERPARTS - This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

         17. MODIFICATION - This Agreement may not be modified orally or in any
manner other than by an agreement in writing signed by the parties hereto or
their respective successors in interest.

         IN WITNESS WHEREOF, the parties have executed this Agreement as an
instrument under seal and hereunto set their respective hands and seals as of
the day, month and year first above written.

                                        LENDER:

                                        --------------------------------------

                                        By:

                                        Title:

                                       8
<PAGE>   105

                                        TENANT:

                                        --------------------------------------

                                        By:

                                        Title:

                                        LANDLORD:

                                        --------------------------------------

                                        By:

                                        By:

                          COMMONWEALTH OF MASSACHUSETTS

______________ County, SS                                  _______________, 2000

         Then personally appeared before me _______________, the
_____________________ of ________________________, to me personally known, who I
am satisfied signed the foregoing instrument, and who did acknowledge under oath
that he/she signed and delivered the same in his/her capacity as
________________ and that the foregoing instrument is his/her free act and deed
and the free act and deed of such                             .

                                             -----------------------------------
                                             Notary Public
                                             My Commission Expires:

                                       9
<PAGE>   106
                          COMMONWEALTH OF MASSACHUSETTS

____________ County, SS.                                  ________________, 2000

         Then personally appeared before me _______________, the
_____________________ of _____________________, to me personally known, who I am
satisfied signed the foregoing instrument, and who did acknowledge under oath
that he/she signed and delivered the same in his/her capacity as
________________ and that the foregoing instrument is his/her free act and deed
and the free act and deed of such corporation.

                                             -----------------------------------
                                             Notary Public
                                             My Commission Expires:

                          COMMONWEALTH OF MASSACHUSETTS

__________________, SS.                                      _____________, 2000

         Then personally appeared before me __________________, as
____________________, to me personally known, who I am satisfied signed the
foregoing instrument, and who did acknowledge under oath that he signed and
delivered the same in his capacity as ___________ aforesaid and that the
foregoing instrument is his free act and deed as ____________ aforesaid.

                                             -----------------------------------
                                             Notary Public
                                             My Commission Expires:

                          COMMONWEALTH OF MASSACHUSETTS

__________________, SS.                                      _____________, 2000

         Then personally appeared before me __________________, as
____________________, to me personally known, who I am satisfied signed the
foregoing instrument, and who did acknowledge under oath that he signed and
delivered the same in his capacity as ___________ aforesaid and that the
foregoing instrument is his free act and deed as ____________ aforesaid.

                                             -----------------------------------
                                             Notary Public
                                             My Commission Expires:

                                       10
<PAGE>   107

                                  EXHIBIT "K"

                          LANDLORD, TENANT, CONTRACTOR
                              CHANGE PROPOSAL FORM
                          ----------------------------

Project:  _____________________________

          _____________________________          R____________  NR_____________

Proposal No. ______________Date________

From: (Landlord) ______________________          BB___________  TW_____________

To: (Contractor)_______________________

CC: (Tenant)___________________________

________________________________________________________________________________

Step 1: Contractor:  Provide an estimate for the described work.
        Architect:   Develop proper plans and specifications to clarify
                     described work.
        Description: (List Drawings)
        -----------

        Landlord:__________________________ Reason:_____________________________
________________________________________________________________________________

Step 2: Contractor: Proceed with work as definitive plans become available.

        Landlord:__________________________ Date:_______________________________
________________________________________________________________________________

Step 3: Cost of Work
        a. Cost of the work                      $_______________
           (See attached breakdown)
        b. Add construction fee                  $_______________
        Total Cost of Work                       $_______________

Submitted by:____________________________________________  _____________________
Dennis G. Bailey, Vice President & Construction Manager    Date
________________________________________________________________________________

Step 4: The submitted Cost of Work has been reviewed and is (not) approved.

        ________________________________________  _________________________
           Architect                                      Date

        Design Fees -                               $___________________
        TOTAL COST OF PROPOSAL                      $___________________
________________________________________________________________________________

Step 5: FINAL ACTION

        a. The Tenant___________________________ Hereby agrees to reimburse the
                            Name of Firm
           Landlord the Total Cost of Proposal shown in Step 4 above.

        ________________________________________  _________________________
           Authorized Tenant's Representative             Date

        b. This bulletin is approved (rescinded) and the work above is (not) to
           be performed. Cost of this work shall be included in Change Order
           No.________

        ________________________________________  _________________________
                    Landlord                               Date

<PAGE>   108
                                   EXHIBIT "L"

                         DEFINITION OF COST OF THE WORK

REIMBURSABLE COSTS:

The following 18 numbered items shall be used to determine and calculate the
Cost of the Work:

1.       The term Cost of the Work shall mean costs necessarily incurred and
         paid by the Contractor in the proper performance of the work. Such
         costs shall be at rates not higher than the standard paid in the
         greater Boston area and shall include the items set forth below.

2.       Wages paid for labor in the direct employ of Gutierrez Construction
         Co., Inc. ("Contractor") in the performance of the work under
         applicable collective bargaining agreements, or under a salary or wage
         schedule agreed upon by the Landlord, and Contractor, and including
         such welfare or other benefits, if any, as may be payable with respect
         thereto.

3.       Salaries of Contractor's personnel when stationed at the field office,
         in whatever capacity employed, and a proportionate share of the project
         manager and construction managers' salaries, whether at the job site or
         in the main office. Personnel engaged at shops or on the road in
         expediting the production or transportation of materials or equipment
         shall be considered as stationed a the field office and their salaries
         paid for that portions of their time spent on the work.

4.       Cost of contributions, assessments or taxes incurred during the
         performance of the work for such items as unemployment compensation and
         social security, insofar as such cost is based on wages, salaries or
         other remuneration paid to employees of the Contractor and included in
         the Cost of the Work under subparagraphs 2 and 3.

5.       The portion of reasonable travel and subsistence expenses of the
         Contractor or of his officers or employees incurred while traveling in
         discharge of duties connected with the work, but not including travel
         and expenses to and from the job site or to attend meetings..

6.       Costs of all materials, supplies and equipment incorporated in the
         work, including costs of transportation thereof.

7.       Payments made by the Contractor to subcontractors for work performed
         pursuant to subcontracts.

8.       Cost, including transportation and maintenance, of all materials,
         supplies, equipment, temporary facilities and hand tools not owned by
         the workers, which are consumed in the performance of the work, and
         cost less salvage value on such items used by not consumed which remain
         the property of the Contractor.

<PAGE>   109
9.       Rental charges of all necessary machinery and equipment, exclusive of
         hand tools, used at the site in performance of the work, whether rented
         from the Contractor or others including installation, minor repairs and
         replacements, dismantling, removal, transportation and delivery costs
         thereof, at rental charges consistent with those prevailing in the
         greater Boston area.

10.      Cost of premiums for all bonds required by Tenant.

11.      Sales, use, or similar taxes related to the work and for which the
         Contractor is liable, which are imposed by any governmental authority.

12.      Permit fees, royalties, damage or infringement of patents and costs of
         defending suits therefor, and deposits lost for causes other than due
         to the Contractor's negligence.

13.      Losses and expenses, not compensated by insurance or otherwise,
         sustained by the Contractor in connection with the work, provided they
         have resulted from causes other than the fault or neglect of the
         Contractor, subcontractors, or those for whom the Contractor is
         responsible. Such losses shall include settlements made with the
         written consent and reasonable approval by Landlord and Tenant. If,
         however, such loss requires reconstruction and the Contractor is placed
         in charge thereof, he shall be paid for his services a fee of ten
         percent (10%) of the cost of such work.

14.      Minor expenses such as telegrams, long distance telephone calls,
         telephone service at the site, expressage, drawing reproduction, mail
         service, special deliveries, and similar petty cash items incurred in
         connection with the Tenant's Work.

15.      Cost of all removal of debris and clean up.

16.      Costs incurred due to an emergency affecting the safety of persons and
         property.

17.      Other costs incurred in the performance of the work if and to the
         extent approved in advance in writing by the Tenant.

18.      The cost of temporary power and heat.

                                       2
<PAGE>   110
                                   EXHIBIT "M"

                                   ALLOWANCES

         -        $3.50 per rentable square foot for Tenant's costs for project
                  management, space planning, architectural and engineering for
                  the Tenant's Work. Landlord hereby acknowledges and agrees
                  that such allowance shall be paid by Landlord within ten (10)
                  days of Landlord's receipt of an invoice therefor. It is
                  hereby acknowledged and agreed to by Landlord that Tenant
                  shall have the right to apply such portion of any unused
                  allowance to other costs due from Tenant pursuant to Article
                  III hereof, Tenant hereby acknowledging and agreeing that in
                  no event shall Landlord be required to actually reimburse
                  Tenant out-of-pocket for any such unused amount.

         -        $10.00 per rentable square foot to be applied against the
                  costs due from Tenant pursuant to Article III hereof.
<PAGE>   111
                                   EXHIBIT "N"

                              Intentionally Deleted
<PAGE>   112
                                   EXHIBIT "O"

                             GUARANTY OF COMPLETION

         WHEREAS, Michelson Farm-Westford Technology Park X Limited Partnership
("Landlord") entered into a Lease dated as of ________, 2000 (hereinafter, the
"Lease"), with Unisphere Solutions, Inc. ("Tenant") with respect to certain
demised premises located in the building situated at 10 Technology Park Drive,
Westford, Massachusetts (as in the Lease more particularly defined, the
"Premises"), and

         WHEREAS, The Gutierrez Company is the managing member of the Landlord;
and

         WHEREAS, as an inducement to Tenant to enter into the Lease, the
undersigned will guaranty the construction obligations of Landlord under Article
III of the Lease.

         NOW, THEREFORE, in consideration of the Lease and the covenants herein
set forth, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the undersigned hereby agrees as
follows:

         The undersigned hereby absolutely and unconditionally guarantees to
Tenant the due and punctual performance of all of Landlord's or of Landlord's
general contractor's (Gutierrez Construction Co., Inc.'s) construction
obligations and responsibilities as Landlord under Article III of the Lease,
including, without limitation, the warranties set forth in Section 3.7 of the
Lease, and including the payment and discharge of all claims and demands for
labor used for or in connection with the construction and equipping of such
construction so that the property upon which the Premises is located shall be
and remain free and clear of mechanics' and materialmen's liens, but excluding
all claims and demands for labor and materials used for or in connection with
the Tenant's work not constructed by Landlord or its general contractor pursuant
to Article III of the Lease.

         The undersigned hereby covenants and agrees that, upon written notice
by Tenant, but only after default by Landlord, or its general contractor, as the
case may be, and expiration of applicable grace periods set forth in the Lease,
or if none, thirty (30) days upon receipt of such notice from Tenant, it will
promptly perform all of such construction responsibilities of Landlord under
said Article III of the Lease during the construction of the Building of which
the Premises form a part.

         The undersigned hereby agrees, as principal obligor and not as a
guarantor only, to pay to Tenant forthwith upon demand all costs and expenses
(including court costs and reasonable legal fees) incurred or expended by Tenant
in connection with this Guaranty and the defense and/or enforcement hereof.

         No provision of this Guaranty can be changed, waived or discharged
except by an instrument in writing signed by Tenant and the undersigned. No
course of dealing or delay or omission on the part of Landlord in exercising any
right shall operate as a waiver thereof or otherwise be prejudicial thereto.

<PAGE>   113
         This Guaranty is intended to take effect as a sealed instrument to be
governed by and construed in accordance with the laws and courts of the
Commonwealth of Massachusetts and shall inure to the benefit of Tenant and its
successors and assigns, and shall be binding on the undersigned and its
successors and assigns.

         IN WITNESS WHEREOF, the undersigned has executed this Guaranty under
seal on this _____ day of ________, 2000.

                                            GUARANTOR:
                                            THE GUTIERREZ COMPANY

                                         By:
                                            Arturo J. Gutierrez
                                            President

                          COMMONWEALTH OF MASSACHUSETTS

COUNTY OF MIDDLESEX

         Then appeared the above named Arturo J. Gutierrez, the President of The
Gutierrez Company, who acknowledged the foregoing instrument to be his free act
and deed in his capacity as aforesaid, before me, this ___ day of ___________,
2000.

                                            ------------------------------------
                                            NOTARY PUBLIC
                                            My Commission Expires:

                                       2
<PAGE>   114
                                   EXHIBIT "P"

                                   MARKET RENT

         The market rent for the Premises shall be the then fair market rent for
similar space in similar Class A office buildings in the Town of Westford, which
such rent (the "Market Rent") shall be determined as follows:

(a)      The Market Rent shall be proposed by Landlord within fifteen (15) days
         of receipt of Tenant's notice that it intends to exercise its option to
         extend the Term as specified in Exhibit F of this Lease hereof (the
         "Landlord's Proposed Market Rent"). The Landlord's Proposed Market Rent
         shall be the Market Rent unless Tenant notifies Landlord, within
         fifteen (15) days of Tenant's receipt of Landlord's Proposed Market
         Rent, that Landlord's Proposed Market Rent is not satisfactory to
         Tenant ("Tenant's Rejection Notice").

(b)      If Tenant delivers Tenant's Rejection Notice and the Market Rent is not
         otherwise agreed upon by Landlord and Tenant within forty-five (45)
         days after Landlord's receipt of Tenant's notice that it intends to
         exercise its option to extend the Term, then the Market Rent shall be
         determined by the following appraisal procedure:

         1.       Within five (5) days of the expiration of said forty-five (45)
                  day period, Tenant shall give notice to Landlord, which notice
                  shall specify the name and address of the appraiser designated
                  by Tenant (the "Tenant's Appraisal Notice"). Landlord shall
                  within five (5) days after receipt of Tenant's Appraisal
                  Notice, notify Tenant of the name and address of the appraiser
                  designated by Landlord. Such two appraisers shall, within
                  twenty (20) days after the designation of the second
                  appraiser, make their determinations of the Market Rent in
                  writing and give notice thereof to each other and to Landlord
                  and Tenant. Such two (2) appraisers shall have twenty (20)
                  days after the receipt of notice of each other's determination
                  to confer with each other and to attempt to reach agreement as
                  to the determination of the Market Rent. If such appraisers
                  shall concur in such determination, they shall give notice
                  thereof to Landlord and Tenant and such concurrence shall be
                  final and binding upon Landlord and Tenant. If such appraisers
                  shall fail to concur as to such determination within said
                  twenty (20) day period, they shall give notice thereof to
                  Landlord and Tenant and shall immediately designate a third
                  appraiser. If the two appraisers shall fail to agree upon the
                  designation of such third appraiser within five (5) days after
                  said twenty (20) day period, then they or either of them shall
                  give notice of such failure to agree to Landlord and Tenant
                  and if Landlord and Tenant fail to agree upon the selection of
                  such third appraiser within five (5) days after the
                  appraiser(s) appointed by the parties give notice as
                  aforesaid, then either party on behalf of both may apply to
                  the American Arbitration Association or any successor thereto,
                  or on his or her failure, refusal or inability to act, to a
                  court of competent jurisdiction, for the designation of such
                  third appraiser.

<PAGE>   115
         2.       All appraisers shall be independent real estate appraisers or
                  consultants who shall have had at least seven (7) years
                  continuous experience in the business of appraising real
                  estate in the suburban Boston area.

         3.       The third appraiser shall conduct such hearings and
                  investigations as he or she may deem appropriate and shall,
                  within ten (10) days after the date of his or her designation,
                  make an independent determination of the Market Rent.

         4.       If none of the determinations of the appraisers varies from
                  the mean of the determinations of the other appraisers by more
                  than ten (10%) percent, the mean of the determinations of the
                  three (3) appraisers shall be the Market Rent for the
                  Premises. If, on the other hand, the determination of any
                  single appraiser varies from the mean of the determinations of
                  the other two (2) appraisers by more than ten (10%) percent,
                  the mean of the determination of the two (2) appraisers whose
                  determinations are closest shall be the Market Rent.

         5.       The determination of the appraisers, as provided above, shall
                  be conclusive upon the parties and shall have the same force
                  and effect as a judgment made in a court of competent
                  jurisdiction.

         6.       Each party shall pay fees, costs and expenses of the appraiser
                  selected by it, its own counsel fees, and one-half (1/2) of
                  all other expenses and fees of any such appraisal.

                                        2
<PAGE>   116
                                   EXHIBIT "Q"

                     EXISTING EXCLUSIVE USES AND EXCLUSIONS

EXCLUSIONS:

Lotus - Building 3 Lease
         -  Novell
         -  Netscape
         -  Microsoft
         -  Hewlett Packard

Emerson - Building 7 Lease
         -  Tenants whose principal use is offering medical and
         diagnostic treatment services and/or health education and wellness
         promotion educational services

Chili's

         -  Restaurant exclusion for 3-mile radium of Westford Technology
         Park excluding cafeterias in buildings

RIGHTS OF FIRST REFUSAL:

Lotus - Building 3 Lease
        -   Building 4
        -   Building 6

Lotus - Building 1 Lease
        -   Building 1

Emerson -   Building 7 Lease
        -   Building 7

RIGHTS OF FIRST OFFER:

ENSR - Building 2 Lease
        -   Building 2 - any space that becomes available

UNISPHERE - BUILDING 10 LEASE (PHASE I)

        -   Building 2
        -   Building 4
        -   Building 6
<PAGE>   117
                                   EXHIBIT "R"

                              Intentionally Deleted
<PAGE>   118

                                                                     EXHIBIT "S"

               Westford Technology Park - Building 10 - Phase II
       Preliminary Construction Schedule - Base Building & T.I. - 6/21/00

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------
                                                Start               End
Task Name                                       Date                Date         Duration
-------------------------------------------------------------------------------------------
<S>                                           <C>                <C>             <C>
1.)  Authorization & Required Dwgs             6/19/00            9/14/00        62.0 days
-------------------------------------------------------------------------------------------
      Authorization to Start Const.            6/19/00            6/19/00         0.0
-------------------------------------------------------------------------------------------
      Receipt of Base Bldg. Dwgs               6/23/00            6/23/00         0.0
-------------------------------------------------------------------------------------------
      Tenants Undergrd. Util. Plan             8/11/00            8/11/00         0.0
-------------------------------------------------------------------------------------------
      Tenant Improvement ConstDwgs             9/15/00            9/15/00         0.0
-------------------------------------------------------------------------------------------
2.)  Order Major Bldg. Components              6/26/00            6/26/00         0.0
-------------------------------------------------------------------------------------------
3.)  Site Excavation-Cuts&Fills                7/10/00             8/4/00        20.0 days
-------------------------------------------------------------------------------------------
4.)  Bldg. Excavation&Backfill                 7/31/00            8/30/00        23.0 days
-------------------------------------------------------------------------------------------          [BAR CHART: REFLECT
5.)  Site Utilities                            7/31/00             9/1/00        25.0 days           THE DATE IN THE TABLE]
-------------------------------------------------------------------------------------------
6.)  Bldg. Foundations                         7/31/00             9/5/00        26.0 days
-------------------------------------------------------------------------------------------
7.)  Bldg. Undergrd. Util.                      9/5/00            9/20/00        12.0 days
-------------------------------------------------------------------------------------------
8.)  Gravel Base for S.O.G.                    9/18/00            9/22/00         5.0 days
-------------------------------------------------------------------------------------------
9.)  Slab on Grade                             9/25/00            9/27/00         3.0 days
-------------------------------------------------------------------------------------------
10.) Gravel Base @ Bit. Paving                  9/5/00            9/22/00        14.0 days
-------------------------------------------------------------------------------------------
11.) Bit. Paving Binder                        9/27/00            9/29/00         3.0 days
-------------------------------------------------------------------------------------------
12.) Granite Curb & Bit. Berm                  10/2/00           10/13/00         9.0 days
-------------------------------------------------------------------------------------------
13.) Struct. Steel/Joist/Deck                  10/3/00           11/10/00        28.0 days
-------------------------------------------------------------------------------------------
14.) Stair                                    10/30/00            11/8/00         8.0 days
-------------------------------------------------------------------------------------------
15.) Precast Concrete                         10/30/00           11/10/00        10.0 days
-------------------------------------------------------------------------------------------
16.) Pour 2nd & 3rd Flr. Slabs                10/26/00            11/3/00         7.0 days
-------------------------------------------------------------------------------------------
17.) Windows & Entrances                       11/6/00           12/15/00        28.0 days
-------------------------------------------------------------------------------------------
18.) Roofing & Flashing                       11/14/00           11/22/00         7.0 days
-------------------------------------------------------------------------------------------
19.) Rooftop HVAC Units                       11/20/00           11/21/00         2.0 days
-------------------------------------------------------------------------------------------
20.) Rough-in M.E.P.                          11/14/00            1/12/01        41.0 days
-------------------------------------------------------------------------------------------
21.) Drywall & Rough Carpentry                 12/4/00             2/9/01        47.0 days
-------------------------------------------------------------------------------------------
22.) Deliver H.M. Frames                      12/11/00           12/11/00         0.0
-------------------------------------------------------------------------------------------
23.) Ceiling Grid                              1/16/01            2/16/01        24.0 days
-------------------------------------------------------------------------------------------
24.) M.E.P. Fixtures & Devices                 1/22/01            2/21/01        22.0 days
-------------------------------------------------------------------------------------------
25.) Painting                                  2/5/010             3/9/01        24.0 days
-------------------------------------------------------------------------------------------
26.) Fin. Carpentry & Casework                 2/12/01            3/16/01        24.0 days
-------------------------------------------------------------------------------------------
27.) Glass & Glazing                            2/7/00             3/9/00        23.0 days
-------------------------------------------------------------------------------------------
28.) Ceiling Tile                              2/20/01            3/16/01        19.0 days
-------------------------------------------------------------------------------------------
29.) Elec. Plates & Finish                      2/5/01            3/30/01        39.0 days
-------------------------------------------------------------------------------------------
30.) Carpet & V.C.T.                           2/28/01            3/23/01        18.0 days
-------------------------------------------------------------------------------------------
31.) System Furniture                           3/7/01            3/30/01        18.0 days
-------------------------------------------------------------------------------------------
</TABLE>

                                                                     EXHIBIT "S"
<PAGE>   119
                                   EXHIBIT "T"

                                 NOTICE OF LEASE

         In accordance with the provisions of Massachusetts General Laws (Ter.
Ed.) Chapter 183, Section 4, as amended, notice is hereby given of a certain
lease (hereinafter referred to as the "Lease") dated as of ________, 2000 by and
between Michelson Farm-Westford Technology Park X Limited Partnership
(hereinafter referred to as "Landlord") and Unisphere Solutions, Inc.
(hereinafter referred to as "Tenant").

                              W I T N E S S E T H:

         1.       The address of the Landlord is c/o The Gutierrez Company, One
                  Wall Street, Burlington, Massachusetts 01803.

         2.       The address of the Tenant is 5 Carlisle Road, Westford,
                  Massachusetts 01886.

         3.       The Lease was executed on ____________, 2000.

         4.       The Term of the Lease is a period of ten (10) years beginning
                  on the Term Commencement Date determined in accordance with
                  Section 3.2 of the Lease, currently scheduled for June 30,
                  2001.

         5.       Subject to the provisions of the Lease, the Tenant has the
                  option to extend the Term of the Lease for two (2) successive
                  five (5) year terms pursuant to Exhibit "F" of the Lease.

         6.       The Lot and the Park, as such terms are defined in the Lease,
                  are subject to the covenants and agreements contained in
                  Exhibit "I" of the Lease.

         7.       The demised premises is a three (3) story building containing
                  approximately seventy-five thousand (75,000) rentable square
                  feet located at 10 Technology Park Drive, Westford,
                  Massachusetts 01886, and the areas of which are the subject of
                  all appurtenant rights and easements set forth in Sections 2.1
                  and 10.14 of the Lease.

         8.       The deed for the demised premises was recorded on
                  ______________ with the Middlesex North Registry of Deeds in
                  Book _____, Page ____, as more particularly described on
                  Exhibit "A" hereto.

         This Notice of Lease has been executed merely to give notice of the
Lease, and all of the terms, conditions and covenants of which are incorporated
herein by reference. The parties hereto do not intend this Notice of Lease to
modify or amend the terms, conditions and covenants of the Lease which are
incorporated herein by reference.
<PAGE>   120
         IN WITNESS WHEREOF, the parties hereto have duly executed this Notice
of Lease this ___ day of ______________, 2000.

                                        LANDLORD:
                                        MICHELSON FARM-WESTFORD
                                        TECHNOLOGY PARK X
                                        LIMITED PARTNERSHIP

                                        By:  The Gutierrez Company,
                                             Sole General Partner

                                             By:
                                                --------------------------------
                                                  Arthur J. Gutierrez, President

                                        Dated:
                                              ----------------------------------

                                        TENANT:
                                        UNISPHERE SOLUTIONS, INC.

                                        By:
                                           -------------------------------------
                                        Its:
                                            ------------------------------------
                                        Dated:
                                              ----------------------------------

                          COMMONWEALTH OF MASSACHUSETTS

MIDDLESEX, SS.                                                ____________, 2000

         Then personally appeared before me Arthur J. Gutierrez, President of
The Gutierrez Company, sole general partner of Michelson Farm - Westford
Technology Park X Limited Partnership and acknowledged the foregoing instrument
to be his free act and deed as President aforesaid and the free act and deed of
The Gutierrez Company and Michelson Farm Westford Technology Park X Limited
Partnership.

                                                --------------------------------
                                                NOTARY PUBLIC
                                                My Commission Expires:

                                        2
<PAGE>   121
                          COMMONWEALTH OF MASSACHUSETTS

_______________, SS.                                          ____________, 2000

         Then personally appeared before me ________________, as
________________ of Unisphere Solutions, Inc., and acknowledged the foregoing
instrument to be his/her free act and deed as _________ aforesaid.

                                                --------------------------------
                                                NOTARY PUBLIC
                                                My Commission Expires:

                                       3
<PAGE>   122
                                   EXHIBIT "U"

                              Intentionally Deleted

                                       4<PAGE>   1

EXECUTION VERSION                      1
                                                                   EXHIBIT 10.24

--------------------------------------------------------------------------------
        Confidential Materials are omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.

--------------------------------------------------------------------------------

                   MASTER MANUFACTURING AND PURCHASE AGREEMENT
                        BULL HN INFORMATION SYSTEMS INC.
                                       AND
                              CASTLE NETWORKS, INC

Agreement entered into this 22nd day of September, 1999, by and between BULL HN
INFORMATION SYSTEMS INC., ACTING THROUGH ITS BULL ELECTRONICS UNIT, a Delaware
corporation, with offices at 1001 Pawtucket Boulevard, Lowell Massachusetts,
01854, hereinafter referred to as "BULL", and CASTLE NETWORKS, INC., a Delaware
corporation, with principal offices at 1 Executive Drive, Chelmsford, MA, 01824,
hereinafter referred to as "CNI".

Whereas, BULL agrees to manufacture and provide warranty and post warranty
repair support for the products described on attached Schedule 1 ("Products")
and sell the finished Products exclusively to CNI. CNI agrees to purchase the
finished Products and post warranty repair services for such finished Products
from BULL. The manufacture, sale, purchase, warranty and post warranty repair of
the finished Products will be governed by the terms and conditions of this
Agreement. Additional products as agreed to by the parties in a written
amendment signed by duly authorized representatives of each party may be added
to this Agreement from time to time, whereupon they shall be treated as
"Products" under the terms of this Agreement such that the terms of this
Agreement will cover any and all product manufactured by BULL for CNI.

Now, therefore, the parties hereby agree as follows:

This Agreement consists of the attached following GENERAL TERMS AND CONDITIONS
and the following Schedules (as applicable):

                  Schedule 1 - Product Specifications and Product Pricing
                  Schedule 2 - Quality Requirements
                  Schedule 3 - Approved Vendor List
                  Schedule 4 - Test Programs and Fixtures

1.   PRODUCT PURCHASE PRICES

1.1  Purchase prices ("Purchase Prices") for the Products are set forth on
Schedule 2 and are assumed to provide the basis as the "not to exceed" purchase
price for the term of the agreement. Prices shall be adjusted in accordance with
the provision below, entitled Continuous Improvement. Purchase Prices are FOB
common carrier at BULL's plant of manufacture and are net of all taxes, duties,
and all other charges. Freight costs shall be separately invoiced to CNI based
on BULL's actual costs.

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   2

EXECUTION VERSION                      2

Confidential Materials are omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

1.2  Price decreases based upon the pricing formula in 1.4 below, shall be
passed on to CNI as they occur, except as otherwise specifically set forth
herein. All Product Purchase Prices will be reviewed by CNI and BULL on a
quarterly basis to commence on or about the 90th day following the initial
agreement's effective date. CNI will be given thirty (30) days notice of any
price change which apply only to orders scheduled after the effective date of
the price change as agreed to by the parties. Only in the event of any
Industry-wide or sole source "custom component" shortage of components affecting
price or delivery schedules, will CNI agree to negotiate with BULL equitable
upward adjustments to the Purchase Prices and delivery schedules, otherwise
prices are not to increase for the following one year term.

CNI recognizes that as prices on components decline, BULL may have long lead and
custom component Inventory on hand in excess of 30 days supply. Only for long
lead time and custom parts for which CNI has approved BULL to purchase will
price reductions be delayed until CNI's attributable share of the higher cost
components are consumed.

1.3  Subject to adjustments under this Agreement the Purchase Price for Products
shall be set forth in Schedule 1 attached hereto, as amended from time to time
by mutual written agreement of the parties.

1.4  Purchase Prices for Products shall be based upon component and
manufacturing cost plus an agreed to gross profit margin of [**] percent
([**]%). Purchase Prices shall be adjusted for the following factors:

*    verified increases, beyond the reasonable control of BULL due to broad
     shortages of standard components or shortages of custom components as
     specified by Castle, in the actual costs for such custom components;

*    decreases in Material Components costs or manufacturing overhead;

*    Continuous Improvement adjustments; or

*    increases in overall manufacturing volumes and run volumes.

2.   QUALITY IMPROVEMENT

2.1  BULL shall have a documented plan for continuously assessing and improving
the quality and reliability of Products. BULL's Quality Improvement Plan (QIP)
shall incorporate a well-defined set of metrics, in a form mutually agreed to by
the parties, that will assess BULL's internal manufacturing, procurement and
logistics efficiency in order to improve BULL's performance for Products sold to
CNI. Metric Collection, analysis and reporting should be conducted on a
continual basis. Both field performance and in-process data shall be utilized.
All information in BULL's QIP shall be made available for review by CNI,
including, but not limited to, plans, procedures and results, provided that such
information shall be considered BULL

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   3

EXECUTION VERSION                      3

Confidential Materials are omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

Confidential and Proprietary and treated in accordance with the provisions of
this Agreement governing the use of Confidential and Proprietary Information.

3.   CONTINUOUS IMPROVEMENT

3.1  CNI and BULL agree that the parties shall identify areas for BULL's
continuous improvement in cost, ("Continuous Improvement") over the term of this
Agreement with regard to board level assemblies. CNI and BULL agree that BULL
will use its commercially reasonable best efforts to achieve at a minimum [**]
percent ([**]%) Continuous Improvement in efficiency and cost Improvements, to
CNI at the commencement of Year two (2) of this Agreement Year two (2) shall be
defined as commencing precisely one (1) year after the date on which this
Agreement shall take effect. CNI and BULL further agree that, should this
Agreement be extended, at the commencement of Year three (3) of this Agreement
BULL will use its commercially reasonable best efforts to achieve at a minimum
[**] percent ([**]%) Continuous Improvement over and above those Continuous
Improvement savings achieved at the commencement of Year two (2). Year three (3)
shall be defined as commencing precisely two (2) years after the date on which
this Agreement shall take effect. However, should BULL have the ability to offer
Continuous Improvement savings prior to the commencement of Year two (2) of this
Agreement, CNI shall receive such savings when such savings may feasibly be
offered, subject to the limitations on passing on such savings as are set forth
in Section 1.2.

3.2  For the purpose of this section, the term "Continuous Improvement" shall
mean improved cost measured by one or more dearly measurable parameters, taken
together, on a year over year basis. The Continuous Improvement shall be
measured over the Products purchased.

3.3  If BULL fails to meet Continuous Improvement commitments based upon the
identified parameters within the time frames set forth, then BULL must present
to CNI a detailed competitive analysis by component for each board level item
purchased. The competitive analysis will show component, quantity purchased,
vendor costs from the vendor(s) on the AVL during the past 12 months and cost
BULL paid for components. For lost savings (Continuous Improvements)
opportunities of a material nature involving the "Category A" Material
Components, BULL will present a plan to recapture savings over like time frame's
future purchases. For the purposes of this Agreement "Category A Components" are
those components identified as such on the mutually agreed to costed bills of
Materials, which components are specified by CNI and are either typically
unique, high cost and/or custom.

In CNI's sole discretion, failure by BULL to demonstrate the ability to deliver
competitive priced product will result in termination of this Contract.

3.4  BULL and CNI shall meet once every three months to assess BULL's progress
towards implementation of Continuous Improvement commitments. These quarterly
meetings shall also serve as the appropriate forum for CNI and BULL to discuss
all issues related to Continuous Improvement goals.

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   4

EXECUTION VERSION                      4

4.   CNI PURCHASE ORDERS

4.1  Material Components will be purchased and Products will be manufactured and
shipped according to a mutually agreed schedule and consistent with applicable
Product Lead-Times of no longer than ninety (90) days, unless otherwise agreed
in writing by the parties. Once agreed to, purchase of Material Components as
well as manufacture and shipment of Products will be in accordance with CNI's
Purchase Orders ("Purchase Orders").

Purchase Orders may be issued in hard copy or electronically ("EDI"), subject to
the parties having entered into a mutually acceptable EDI Agreement, and will be
issued at intervals as mutually agreed. Purchase Orders are firm and will cover
a minimum of ninety (90) days or the stated lead times. Purchase Orders will
state the item(s) to be purchased, the number of Products to be manufactured and
shipped during the period covered by the Purchase Order, as well as CNI's
required delivery date, (which required delivery date shall be consistent with
then current Product Lead Times unless otherwise agreed in writing by the
parties) and agreed to unit price consistent with the terms of this Agreement.
Purchase Orders will be accepted or rejected in writing by BULL within three (3)
business days of receipt for forecasted quantities, but in no event more than
five (5) business days. Orders not so rejected are deemed accepted. BULL shall
have the right to reject only those Purchase Orders for Product that are not
issued in accordance with the terms of this Agreement. In the event that CNI
suffers a material adverse change in its credit or financial situation or
payment history which in BULL's reasonable judgment puts BULL at substantially
greater credit risk, BULL may require acceptable security or guarantees for
payment or pre-payment of orders, subject to a reasonable pre-payment discount,
if such prepayment discount is appropriate, until such time as CNI's
creditworthiness is restored.

Any Purchase Order shall otherwise automatically be deemed to include, without
the necessity of reference, all the other terms and conditions of this
Agreement. The preprinted terms and conditions on the face and reverse side of
each Purchase Order or order acknowledgement shall automatically be deemed
deleted and inapplicable without the necessity of a statement to that effect on
the face of the Purchase Order.

4.2  Delivery F.O.B. common carrier at BULL's plant of manufacture of any
Product subject to an accepted Purchase Order shall be made in accordance with
the confirmed date of delivery set forth in BULL's acceptance of the Purchase
Order, where such confirmed date shall be the requested delivery date if such
requested delivery date is either (a) consistent with BULL's then quoted Product
Lead-Times or (b) consistent with BULL's written agreement to delivery earlier
than the then quoted Product Lead-Times, provided that in either event, BULL has
received all CNI supplied Documentation and Tooling, if any are required. BULL
shall have the right to deliver Product F.O.B. BULL's plant of manufacture
either on the confirmed delivery date or up the five (5) business days earlier
than the confirmed delivery date for the delivery to be considered "On-Time".
BULL will provide CNI with monthly reports of its On-Time delivery record and
shall review with CNI on a quarterly basis such reports. If BULL fails to
deliver a Product On-Time due to causes within BULL's control, CNI's sole and
exclusive remedy and BULL's entire liability shall be for CNI to terminate this
Agreement upon written notice to BULL, subject to CNI's obligation to pay for
Product covered by Purchase Order accepted by BULL prior to the date of CNI's
notice of termination and CNI's obligation to pay BULL for

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   5

EXECUTION VERSION                      5

Material Components procured by BULL as of the date of CNI's notice of
termination based on CNI's Purchase Orders and the first ninety (90) days of
CNI's then current Product Forecast

4.3  CNI shall provide BULL on a monthly basis with a twelve (12) month rolling
forecast of Product purchases broken down by calendar month (the "Forecast").
The Forecast beyond ninety (90) days (or some other mutually agreed period) are
for planning purposes only, are not firm.

4.4  BULL will purchase only the Material Components required to manufacture
Products according to the quantity and delivery schedules set forth in Purchase
Orders issued by CNI during the term of this Agreement. BULL will purchase
Material Components for the Products according to CNI's Approved Vendor List
("AVL"). With CNIs prior written consent which my be evidenced through CNI
Purchase Orders for Material Components, BULL may purchase Material Components
in excess of the requirements set forth for Products subject to CNI issued,
non-cancellable, nonreschedulable Purchase Orders such as Long Lead Time
Material Components or Minimum Buy Material Components. These instances will be
discussed and agreed to in writing by the parties prior to any actual purchase.

For purposes of this Agreement, the term "Long Lead Time Material Component" is
defined as those Material Components either identified on the BOM or which
cannot be delivered to BULL's factory within the then current Product Lead-Time,
as quoted by BULL to CNI for a particular Product. A Product's "Lead-Time" is
defined as the amount of time following BULL's acceptance of CNI's Purchase
Order for a Product that is required for BULL, in the exercise of its reasonable
commercial efforts to (a) receive all Material Components, Documentation and
Tooling, (b) manufacture and assemble, if applicable, the Product to CNI's
Specifications and (c) deliver the Products F.O.B. BULL's factory. BULL shall
provide CNI with an update to the list of Long Lead Time Material Components on
a quarterly basis. If BULL provides no update, CNI may rely upon the previously
provided list of Long Lead Time Material Components.

For purposes of this Agreement the term "Minimum Buy Material Component" is
defined as those Material Components which BULL must procure for CNI in a
quantity that exceeds the quantity that BULL needs to complete the build out of
the quantity of Products subject to accepted Purchase Orders but which, when
procured in such quantity, may allow CNI to benefit from a reduced material cost
and lower Product Purchase Price. BULL shall provide CNI with an update to the
list of any Minimum Buy Material Components on a quarterly basis. If BULL
provides no update, CNI may rely upon the previously provided list of Minimum
Buy Material Components.

5.   PAYMENT TERMS

5.1  Payment terms are the following: net thirty (30) days from invoice date in
United States dollars. The invoice date for Product shall be no earlier than the
ship date. Acceptance of a partial payment will not be a waiver of the right to
be paid the remainder due.

In addition, if CNI fails to pay any sums by their due date, BULL shall have the
right to invoice an annual amount of interest on past due amounts equal to the
then current annual prime rate of interest plus three percentage points. BULL
shall have the right to reject Purchase Orders and/or withhold shipment of
Products subject to accepted Purchase Orders if CNI no longer satisfies

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   6

EXECUTION VERSION                      6

BULL's reasonable credit requirements until such time as CNI comes into
compliance with such requirements and/or provides BULL with acceptable security
or guarantees for payment. Notwithstanding the above, BULL's right to invoice
interest for Products delivered late due to factors within Bull's reasonable
control shall arise only after that number of days that the Product was late
following the due date, with interest accruing as of the original due date.

Authorized Credit Limit Process: As of the Effective Date, BULL shall reasonably
determine CNI's maximum credit limit based on a review of applicable financial
information from CNI (the "'Authorized Credit Limit"). If, at any time during
the Term of this Agreement the aggregate dollar value of (a) BULL's issued but
unpaid invoices for Products and other Material Components or services under
this Agreement, (b) CNI's issued Purchase Orders that have been accepted by BULL
and (c) the material and material handling cost of Material Components procured
by BULL for CNI that are Long Lead Time Components and/or Minimum Buy Components
(collectively, the "CNI's Current Account") is equal to or exceeds the
Authorized Credit Limit, BULL shall provide immediate notice of such
circumstance to CNI and if CNI has not remedied the situation within 5 business
days, BULL shall have the right to withhold delivery of any Product subject to
an accepted Purchase Order and/or refuse to accept any new Purchase Orders
unless and until CNI either pays down the CNI's Current Account so that it is
sufficiently below its Authorized Credit Limit to permit BULL to deliver
Products subject to accepted CNI Orders and/or accept new Purchase Orders or
provides BULL with alternative security and/or guarantees reasonably acceptable
to BULL.

At any time during the Term of the Agreement the Authorized Credit Limit may be
reviewed and adjusted upward, downward or maintained the same by BULL based on
material changes in the financial condition of CNI and/or the volume of Products
that CNI is likely to order from BULL. If and to the extent that BULL makes a
change to the Authorized Credit Limit, it shall do so in writing to CNI and the
new Authorized Credit Limit shall be considered the then current Authorized
Credit Limit until BULL provides advance notice to CNI to the contrary.

6.   WARRANTIES, REMEDIES, LIMITATION OF LIABILITY

6.1  BULL warrants that its contracted services, including but not limited to,
fabrication, testing, and handling shall be carried out in a workmanlike manner,
in conformity with Bull's quotes and the agreed upon specifications as set forth
in this Agreement and all schedules and appendices hereto and further shall
result in Products that are free from defects proximately resulting from Bull's
work and services or failure to correctly carry out or complete such work and
services for twelve (12) months from the Product ship date (the "Product
Warranty"),

6.2  In addition, BULL shall use its commercially reasonable best efforts to
obtain from its suppliers any warranties with regard to quality, workmanship and
intellectual property rights indemnification that are transferable to CNI, and
BULL shall so transfer those benefits to CNI so that they are enforceable by
CNI.

6.3  The Product Warranty shall not apply to any defect or nonconformity that is
caused by (i) defect in any Material Components or any related items provided by
CNI, (ii) Product that is abused, damaged, altered or misused other than by
BULL, (iii) Product damaged by external causes not directly contributed to by
BULL, (iv) any defect in a Product' s functionality not

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   7

EXECUTION VERSION                      7

covered by the mutually approved test procedures to be used by BULL, (v) normal
wear and tear, (vi) shipping or transportation after delivery F.O.B. BULL's
factory or (vii) any attempted repair or repair done by any third party not
authorized by BULL.

Notwithstanding anything to the contrary set forth in the immediately preceding
sentence, if BULL purchases Material Components from CNI's designated suppliers
and the Material Components delivered to BULL (a) do not conform to the Material
Components ordered by BULL in terms of manufacturer, manufacturer part number,
BULL part number, quantity or packaging based on BULL's visual inspection or (b)
are discovered by BULL not to be as warranted by the supplier or manufacturer
either by visual inspection or through any testing that BULL has agreed to
perform for the Products as part of the Purchase Price to be paid by CNI for
such Products prior to the shipment of Products from BULL's facility that
includes such Material Components, subject to confirmation by the manufacturer
that the Material Components are not as warranted, BULL shall be responsible for
returning the non-conforming or defective Material Components to CNI's
designated supplier for repair or replacement in accordance with the supplier's
and/or manufactures return and/or warranty procedures, including, without
limitation, warranty exclusions, all at no charge to CNI. Upon receipt by BULL
of repaired or replacement Material Components, BULL shall use the repaired or
replacement Material Components in Products to be built for CNI. BULL shall
notify CNI of any delay in the delivery of Product caused by the receipt of
non-conforming or defective Material Components and shall be relieved of any
liability associated with the delay in delivering Product to CNI that has
non-conforming or defective Material Components.

If CNI discovers Products shipped by BULL to CNI have Material Components that
are not as warranted by the manufacturer within the applicable manufacturer
warranty period, subject to reasonable confirmation by the manufacturer that the
Material Components are not as warranted during the applicable warranty period,
BULL shall assist CNI in the return of any such Material Components to the
supplier or manufacturer and shall work with the supplier or manufacturer to
obtain repaired or replacement Material Components for use by BULL in the
manufacture of replacement Products. Notwithstanding the foregoing, the presence
of Material Components that are not as warranted by the manufacturer in Product
shipped to CNI shall not relieve CNI from its obligation to pay for such
Products if, in conducting the agreed upon incoming inspection, component
assembly and Product tests for which BULL has quoted CNI the Product Purchase
Price, BULL could not have reasonably discovered that the Material Components
were not as warranted nor shall BULL have any liability for any costs incurred
by CNI in the discovery of such Material Components or in the removal of such
Material Components from Product shipped by BULL to CNI. If and to the extent
that CNI elects to have BULL manufacture additional Product using repaired or
replacement Material Components obtained from the supplier or manufacturer, CNI
shall also pay for such additional Products.

The foregoing two paragraphs sets forth BULL's entire liability and CNI's sole
and exclusive remedy in connection with non-conforming Material Components or
Material Components found and confirmed not to be as warranted.

6.4  Completion of Product Acceptance Tests or incoming inspection shall not
void BULL's other warranties hereunder. CNI may perform acceptance testing which
measures a different array of performance criteria but the parties agree that
the mutually agreed upon Product

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   8

EXECUTION VERSION                      8

Acceptance Test Will be the measurement standard to determine if the Product
meets specifications.

6.5  ALL CLAIMS FOR BREACH OF WARRANTY MUST BE RECEIVED BY BULL WITHIN ONE (1)
YEAR AFTER PRODUCT IS SHIPPED TO CNI OR AT CNI'S INSTRUCTION, TO A CNI CUSTOMER.

6.6  EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, BULL MAKES, AND CNI
RECEIVES, NO OTHER WARRANTY, EXPRESS OR IMPLIED. ALL WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE OR USE ARE EXPRESSLY
DISCLAIMED.

6.7  Except as expressly set forth herein, or otherwise agreed to in writing,
BULL makes no warranty that the Products will (i) meet any specification not
made known to and agreed to by BULL, or (ii) receive the approval of or be
certified by underwriters laboratory, any federal, state, local or foreign
government agency (including without limitation The Federal Communications
Commission) or any other person or entity. BULL assumes no responsibility for
obtaining such approvals or certifications, or meeting such specifications.

6.8  As part of the warranty provided by BULL to CNI with respect to the
workmanship of its Products, BULL further warrants that all Product shall be
manufactured in accordance with the following standards:

Workmanship:               J-STD-001
Solder:                    IPC-A-610, Class 2
ESD:                       MIL-STD-1686

In addition, BULL shall provide written documentation of the Year 2000 (Y2K)
compliance of its production machinery, systems and testing or if not yet
compliant present in writing the plan to achieve Y2K compliance with quarterly
status reviews presented to CNI.

6.9  CNI's remedy for breach of the Product Warranty shall be, at BULL's option,
repair or replacement by BULL of defective Products returned to BULL at a
facility of its choice in Massachusetts. Prior to returning any Product that CNI
claims to be not as warranted by BULL, CNI shall follow Bull's reasonable Return
Material Authorization ("RMA") Procedures. BULL shall promptly provide and shall
not unreasonably withhold or delay the issuance of a RMA number. In addition,
BULL's obligation to repair or replace any returned Product after having issued
a RMA number is conditioned on BULL's verification that all of BULL's reasonable
Valid Warranty Claim Requirements have been met. BULL shall be responsible for
all warranty expenses including the costs of incoming and outgoing shipment for
warranty repair, unless the returned Product is found by BULL not to have met
all of BULL's then current Valid Warranty Claim Requirements, in which event CNI
shall pay BULL for the standard rate costs incurred prior to the determination
that such requirements have not been met. All repairs and replacements will be
made and Product will be returned to CNI, or delivered to destination as
directed by CNI, within fifteen (15) days of receipt by BULL. Products requiring
repair more than 2 times shall be replaced by BULL. BULL recognizes that as the
contract manufacturer of CNI Product that CNI does not possess all the test
equipment necessary for in-depth testing prior to

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   9

EXECUTION VERSION                      9

Confidential Materials are omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

return to BULL. CNI shall work with BULL to coordinate and support the fifteen
(15) day cycle. In any instance where BULL fails to deliver repaired or replaced
Product within fifteen (15) days of receipt of defective Product (subject to
material component availability at the time BULL receives the defective
Product), then CNI shall be entitled to a credit of the purchase price of the
defective Product as its sole and exclusive remedy and BULL's entire liability
for single instances of such failure. Should BULL fail, on a continuing basis,
to meet the requirements for repairs set forth herein after notice by CNI and
BULL's failure to cure within a reasonable time, CNI shall have its full rights
and remedies at law or in equity for redress, subject to the limitation of
damages as set forth in Section 6.15.

6.10  BULL's warranty obligations will cease upon the earlier of the agreed upon
warranty period or, in the case of particular Products requiring BULL to have
test equipment on site, then upon BULL's fulfillment of CNI's request to return
any CNI owned applicable test equipment and test fixtures required to fulfill
the warranty repair process.

6.11  BULL shall not be responsible for defects resulting from CNI's failure to
provide accurate and complete manufacturing documentation, unless BULL fails to
advise CNI of errors or omissions which BULL either recognizes or, in the
exercise of due care as a manufacturing sub-contractor, should have recognized.

6.12  BULL will repair and/or upgrade Products which are outside the warranty
period at mutually agreed prices and terms and conditions to be negotiated by
the parties on a per product basis.

6.13  If at least [**] percent ([**]%) of the same type of tested Products by
BULL over at least [**] ([**]) shipments are confirmed by BULL to have the same
or substantially the same defend not resulting from Bull's services failure to
conform to the warranty as provided herein and as a result of CNI's design of
the Product and/or applicable Specifications or where the parties are unable to
reasonably determine the cause of the defect, such defect shall be deemed to be
an epidemic design failure ("Epidemic Design Failure") for purposes of this
Agreement. BULL shall notify CNI of any Epidemic Design Failure and CNI shall
promptly take appropriate corrective action to remedy the Epidemic Design
Failure at its expense, including, without limitation, through appropriate
modifications to the Specification. BULL's obligation with respect to any
Epidemic Design Failure shall be limited to providing CNI with reasonable
technical support and assistance in allowing CNI to diagnose the Epidemic Design
Failure and implement appropriate corrective action, provided that CNI shall
remain liable to BULL for the Product notwithstanding the defect discovered. In
the event that such [**]% level of failures results solely from BULL's services
failure to conform to the warranty as provided herein BULL shall reimburse CNI
for all the costs of any reasonable program to upgrade or replace all such
products at risk of such failure in the field, subject to the limitation of
damages as contained in Section 6.15.

6.14  BULL warrants that it shall maintain all finished goods or consigned
materials which have been purchased by CNI and are on BULL's or BULL's
subcontractor's sites shall be separately stored, labeled as CNI property and
shall be kept free of all liens and attachments.

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<PAGE>   10

EXECUTION VERSION                      10

6.15  In no event shall either party be liable to the other for any indirect,
incidental or consequential damages, Including, without limitation, any lost
profits, provided that the damages that are otherwise covered by indemnities set
forth in this Agreement shall not be excluded by the foregoing sentence. In no
event shall either party's liability for any damages arising out of this
Agreement exceed $2,000,000.

7.    INSPECTION

7.1   CNI will have the right to perform random inspection of Products to be
shipped by BULL and give BULL written notice of any defects or other
discrepancies within two (2) days of inspection. Inspection shall not relieve
BULL of warranty responsibility.

7.2   CNI shall have the right to conduct due diligence inspection and testing
at BULL's, and any of its subcontractors, facilities at any point(s) or on a
continuing basis as CNI may deem appropriate. CNI will provide BULL a reasonable
(usually 2 business days) notice prior to inspection unless the nature of the
inspection results from a direct and immediate impact to CNI Product and
business, in which case, inspection will be immediate. Source Inspection applies
to all Products, sub-assemblies and components. Source Inspection will be
permitted upon Products, sub-assemblies and components by a CNI representative.
When requested, BULL will furnish CNI with full access to its facilities and
those of its subcontractors and the appropriate documentation (i) proving that
the PRODUCT does conform to all contractual specifications, and (ii) showing
BULL's projected failure rate, along with the test data that substantiates the
conformance Products, sub-assemblies and components prior to shipment. CNI
reserves the right to perform testing to confirm the supplied data at BULL's
facility.

7.3   Where CNI Quality Management finds received PRODUCTS do not meet
contractual requirements, the cost of inspection and testing, replacement and
shipping shall be incurred by BULL in accordance with BULL's Warranty for such
PRODUCTS set forth in this Agreement.

7.4   CNI reserves the right to have BULL inspect 100% of any Product that does
not meet contractual Specifications in accordance with BULL's Warranty for such
PRODUCTS set forth in this Agreement at BULL's cost.

7.5 On no less frequently than a quarterly basis, CNI shall share with Bull its
failure analysis of Products at the burn-in and functional test levels to the
extent performed by CNI.

8.    OWNERSHIP OF PRODUCT

8.1   CNI shall retain sole and exclusive Ownership rights to the Product(s)
manufactured by BULL and shall have the exclusive right to market and
manufacture, or have the Product manufactured by third parties at its
discretion, provided that BULL shall have no warranty Obligation with respect to
such third party manufactured Product.

9.    PRIMARY CONTACT PERSON

9.1   Each Party shall assign one individual to act as Primary contact person
for business and one person to act as primary contact person for technical
interactions between CNI and BULL.

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   11

EXECUTION VERSION                      11

Confidential Materials are omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

10.   RESCHEDULING AND CANCELLATION

10.1  CNI may reschedule products previously released for production at no
charge, for a Period of no more than ninety (90) days from the original
scheduled date, for the listed quantities and upon the following terms:

DAYS' NOTICE IN ADVANCE OF
ORIGINAL SCHEDULED DELIVERY
DATE THAT RESCHEDULING NOTICE
IS RECEIVED BY BULL                     % OF PRODUCT ON ORDER
-------------------                     ---------------------
0 - 30                                  [**]%
31 - 60                                 [**]%
61 - 90                                 [**]%

CNI may cancel product at any time subject to the terms of Clause 13.0 Inventory
Indemnification as agreed to by the parties.

Any schedule acceleration or volume increases requested by CNI will be subject
to Material Component availability.

If CNI reschedules any Products subject to accepted Purchase Orders in
accordance with the terms of this Section and if, as a result of such
rescheduling, BULL must hold in its inventory for more than ninety (90) days (i)
Category A Components procured by BULL to complete the manufacture of Products
subject to accepted Purchase Orders that have now been rescheduled and/or (ii)
Work in Process ("WIP") made by BULL to complete the manufacture of Products
subject to accepted Purchase Orders that have now been rescheduled, then BULL
reserves the right to invoice CNI an amount equal to [**] percent ([**]%) of
BULL's Material Component cost for all Category A components so held and WIP
that Bull must hold in its inventory for more than ninety (90) days as a result
of CNI's reschedule request. CNI shall pay the amount invoiced by BULL under the
preceding sentence thirty (30) days from the date of BULL's invoice.

11.   NON-RECURRING ENGINEERING CHARGES

11.1  CNI and BULL will mutually agree on BULL provided non-recurring
engineering, set up and tooling charges ("NRE") required to manufacture the
Products. NRE, set-up, and tooling charges will be paid in full (via an invoice
from BULL) within thirty (30) days after BULL's completion of the NRE item. All
work product (such as: Genrad test fixtures; Unicam programming, Flying probe
test program, etc.) from NRE carried out by BULL under the terms hereof,
including any ideas or concepts either patentable or otherwise shall be owned by
CNI and BULL shall have a right to use such work product solely in the conduct
of this Agreement for the benefit of CNI.

12.   CHANGES TO THE PRODUCTS

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   12

EXECUTION VERSION                      12

Confidential Materials are omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

12.1  BULL will not make any changes to the Products without CNI's prior written
authorization. BULL will make CNI requested engineering changes ("EC") to the
Products as required by the CNI EC. An EC request will include sufficient
information for evaluation of its feasibility and cost impact. BULL will respond
to EC requests in writing and provide cost and other relevant data within ten
(10) business days after receipt of the EC.

12.2  CNI may from time to time change the Specifications for the Products or
the work required of BULL hereunder and BULL agrees to implement the change per
CNI's request and schedule. If changes result in a change in BULL's costs or in
the time for performance an equitable adjustment will be made. Any adjustment
must be in writing and BULL shall not be required to implement such change until
the Parties have mutually agreed upon the price. In the event of a change
necessitated by safety requirements, or law, BULL agrees to implement said
change in a time frame that correlates to the nature of, and timeframe
requirement associated with the event.

12.3  BULL agrees not to make any changes in its processes or manufacturing
standards which would affect form, fit or function of the Product reliability,
maintainability, interchangeability, cosmetic change, without first obtaining
written agreement from CNI. BULL will notify CNI at least ninety (90) days in
advance of any such changes.

12.4  BULL agrees to provide CNI with [**] days' notice in the event they will
no longer be able or willing to produce Product for CNI, and will allow CNI the
opportunity to place a last time buy of Product

For purposes of this Agreement, there shall be "Insufficient Product Demand" for
a Product if there are no quantities of such Product on an accepted Purchase
Order with a scheduled delivery date for at least [**] days. For any Product for
which there is Insufficient Product Demand, BULL shall notify CNI and shortly
thereafter, BULL shall provide CNI with a detailed listing of any Long Lead Time
Components, Minimum Buy Components and other procured but unused Material
Components that were procured by BULL to cover CNI's Purchase Orders (the
"Unused Material List").

BULL and CNI shall negotiate a mutually acceptable disposition of the materials
on the Unused Material List. If the parties fail to mutually agree upon an
acceptable disposition of all of the materials on the Unused Material List
within sixty (60) days following the date that there is Insufficient Product
Demand for the Product(s) that would otherwise require the material on the
Unused Material List, then, BULL shall have the right to invoice and CNI shall
pay BULL within thirty (30) days of the invoice date for BULL's material costs
and material handling costs applicable to the Material Components on the Unused
Material List for which there is no mutual agreement on an acceptable
disposition. BULL shall deliver all Material Components for which BULL invoices
such costs to CNI F.O.B. common carrier at BULL's plant of manufacture, with
delivery occurring on the date BULL issues such invoice.

13.   INVENTORY INDEMNIFICATION

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   13

EXECUTION VERSION                      13

13.1  Upon cancellation of a Purchase Order, or upon expiration of this
Agreement or termination of this Agreement for any reason, CNI shall be
responsible for:

(i)   all finished Products scheduled for shipment within thirty (30) days
      immediately following BULL's receipt of the cancellation or termination
      notice (the "Notice"); and all additional finished goods as mutually
      agreed to in writing, including finished goods that were rescheduled for
      no more than a period of ninety (90) days per Section 10 of this
      Agreement, and

(ii)  all work-in-process at receipt of the Notice; and

(iii) all components, subassemblies and other Material Components purchased to
      fill a Purchase Order or authorized to be purchased by CNI which are on
      hand or on order at receipt of the Notice. Without limitation this
      includes Piece Part Inventory made obsolete or excessive due to changes to
      the Specifications or Products, minimum buy quantities, and reel
      quantities.

Item (i)-(iii) are referred to as the "Termination Inventory". In calculating
the quantity of finished Products under (i) above, Products rescheduled for
manufacture and shipment during the thirty (30) days immediately prior to
receipt of the Notice may be counted by BULL.

13.2  BULL will make every reasonable effort to use and take all steps to
minimize the cost of the Termination Inventory on other current programs at the
Plant where the Products are manufactured, will make every reasonable effort to
cancel all outstanding Material Component orders with vendors, and will attempt
to return piece parts to vendors. CNI will be responsible for costs, charges and
fees actually incurred by BULL to cancel or return any portion of the
Termination Inventory to vendors and, upon mutual agreement, the cost to modify
the Products for other programs.

13.3  Upon sixty (60) days from termination or cancellation, BULL has the right
to invoice CNI for the Termination Inventory remaining after vendor
cancellations and returns and after other program use, as follows: (i) for Piece
Part Inventory and all other items described in Section 13.1 (iii) above, at
BULL's material cost and material acquisition cost. BULL will provide CNI with
evidence of its material cost upon request. (ii) for WIP, at a reasonable pro
rata percentage of the finished Product purchase price; and (iii) for finished
Product, at the Purchase Price, in effect at termination or cancellation. CNI
will be responsible for any negative price differentials between the price BULL
paid for the items described in Section 13.1(iii) and the price at which BULL
was able to return and/or utilize the items on other programs. BULL will credit
CNI for any positive price differentials.

14.   TERM AND TERMINATION

14.1  The term of this Agreement shall be two (2) years from the Effective Date
and, unless terminated as provided for below, will be automatically renewed for
one (1) year periods for as long as BULL retains manufacturing responsibilities
for the Products.

14.2  This Agreement may be terminated by either party upon the occurrence of
any one or more of the following events:

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   14

EXECUTION VERSION                      14

            (i) failure by either party to perform any of its material
      performance obligations under this Agreement and to cure such failure
      within thirty (30) days after receipt of written notice describing the
      failure in sufficient detail, or if the failure cannot be completely cured
      within thirty (30) days, failure to make substantial progress towards a
      cure within the thirty (30) day period; or

            (ii) entering into or filing of a petition, arrangement or
      proceeding seeking: an order for relief under the bankruptcy laws of the
      United States or similar laws of any other jurisdiction; a receivership
      for any of its assets; a composition with or assignment for the benefit of
      its creditors; a readjustment or debt, or its dissolution or liquidation.

14.3  CNI reserves the right to terminate this Agreement at any time for
convenience upon one hundred and eighty (180) days notice without charge or cost
except for any charges accruing pursuant to the terms of Clause 13.0 Inventory
Indemnification.

15.   SPACE ALLOCATION

15.1  BULL agrees to allocate and reserve secured environmentally controlled
space for CNI finished goods inventory, at no charge to CNI. BULL will provide
regular access during working hours as well as access during non-working hours
on an emergency basis.

16.   TRADEMARKS AND PUBLIC ANNOUNCEMENTS

16.1  This Agreement shall not include any license or right for either party to
use any trademark or trade name used or claimed by the other (including but not
limited to the name "Castle Networks, INC." or "BULL" or "BULL ELECTRONICS"),
(the "Trademarks") or coined words or combinations containing the name or parts
thereof in the business name of the other or of any Affiliate or the other in
connection with the business of any of them. All uses of Trademarks by each
party in connection with the products or the packaging thereof shall be in
strict compliance with any conventions of the other concerning the same.

16.2  Neither party shall publicly disclose the existence of this Agreement or
use the other's name in any public announcement or literature, without the
written consent of the other party, and neither party shall disclose the
specific terms and conditions of this Agreement except by written agreement
between the parties or as required by law or court order.

17.   PROPRIETARY DATA

17.1  Any confidential or proprietary data and/or trade secret information
disclosed by CNI to BULL either orally or in writing shall not be used by BULL
except as may be required to manufacture the products sold hereunder, nor shall
either party disclose any of the other's proprietary or confidential data or
trade secret information to third party without the other's prior written
consent, for a period of three (3) years after the date of its original
disclosure, unless such data or information was already known to the general
public in tangible, demonstrable form or the other already had lawful knowledge
of same in tangible demonstrable form or later lawfully acquires same from
another source in tangible, demonstrable, unrestricted form. All such
confidential or proprietary data shall be so labeled by each party and returned
to the disclosing

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   15

EXECUTION VERSION                      15

party upon the earlier of (a) a written request from the disclosing party or (b)
termination of this Agreement.

18.   USE OF SUBCONTRACTORS

18.1  BULL agrees that it will not use any third party subcontractors to provide
services with regard to the manufacture of CNI product without CNI's prior
written consent

18.2  BULL agrees to provide CNI with ninety (90) days' written notice in the
event of a change of location of BULL manufacturing site.

19.   GENERAL

19.1  All work or SERVICES furnished by BULL or by persons furnished by BULL,
including its subcontractors (if any) pursuant to this Agreement shall be
performed in a proper and workmanlike manner and as an Independent Contractor
and not as the agent of CNI. All persons furnished by BULL and its
subcontractors (if any) shall be considered solely BULL's and its
subcontractors' (if any) employees or agents, and BULL and its subcontractors
(if any) shall be responsible for compliance with all laws, rules, and
regulations including, but not limited to employment of labor, hours of labor,
working conditions, worker's compensation, payment of wages, and payment of
taxes, such as unemployment, social security and offer payroll taxes, including
applicable contributions from such persons when required by law. BULL and its
subcontractors (if any) shall indemnify, hold harmless, and defend CNI from and
against any claim or lawsuits arising out of BULL's and its subcontractors' (if
any) failure to comply with any such law, rules or regulations.

19.2  Each party (the "Indemnifying Party") shall indemnify, hold harmless and
defend the other (the "Indemnified Party") from and against any loss, cost
liabilities, claim or demands (including the costs, expenses and attorney's
fees) that may be made by anyone for injuries including death to persons or
damage to property including the resulting from its acts or omissions of the
Indemnifying Party.

CNI shall indemnify, defend and hold BULL harmless from third party claims
arising out of anything provided by CNI or its agents to BULL in connection with
this Agreement including, without limitation, the Product Specifications or due
to the use or resale of any Products by CNI or others, except and to the extent
those third party claims arise out of Bull's negligent acts or failure to comply
with the terms of this Agreement.

19.3  The Indemnifying Party shall not implead or bring any action against the
Indemnified Party and its Affiliates, their respective directors, officers,
employees, agents in connection with any action by any of the Indemnifying
Party's employees for any personal injury (including death) or property damage
that occurs in the course or scope of employment of such person except to the
extent such personal injury or property damage is directly caused by the
negligence of the Indemnifying Party and/or its Affiliates or their employees or
agents. The Indemnified Party and its AFFILIATES will notify the Indemnifying
Party of any written claims or demands against it for which the Indemnifying
Party is responsible hereunder.

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   16

EXECUTION VERSION                      16

19.4  This Agreement and its attachments make up the entire agreement between
the parties regarding the Products. This Agreement supersedes all prior oral and
written agreements and understandings between the parties relating to the
Products, and may only be amended or modified in writing signed by an authorized
representative of each party.

19.5  Unless otherwise agreed, CNI shall be (i) the exporter of record for any
Products and/or Product documentation exported from the United States, and shall
comply with all applicable U.S. export control statutes and regulations, and
(ii) the importer of record for all Products exported from the U.S. and later
imported and returned to CNI or to BULL. BULL will cooperate with CNI in
obtaining any export or import licenses for the Products.

19.6  CNI hereby certifies that it will not knowingly export directly or
indirectly, any U.S. origin technical data or software acquired from BULL or any
direct product of that technical data or software, to any country for which the
United States Government requires an export license or other approval, without
obtaining such approval from the United States Government. BULL will mark any
and all export documentation with the following language when exporting on
behalf of CNI: "These commodities, technology or software were exported from the
United States in accordance with the Export Administration Regulations.
Diversion contrary to U.S. Law is prohibited."

19.7  Except for the Products or portions of the Products which are the other
party's design, each party is responsible for their portion of the design of the
Products. Upon demand, that party will promptly defend, indemnify and hold the
other party, its officers, directors, employees, agents, successors and assigns,
harmless from and against every kind of cost, expense or loss (including
attorneys' fees and legal costs) directly relating to any claim or threatened
claim (a) that any Product or portion of a Product Violates the intellectual
property rights of a third party (foreign or domestic); (b) that the Product has
a design defect; or (c) arising from or related to the distribution, sale or use
of any Product or portion of a Product. The immediately preceding sentence will
apply whether the claim is based upon contract, tort or any other legal theory.

19.8  This Agreement is intended solely for the benefit of the executing parties
and their permitted successors and assigns. No other person or entity shall have
any rights under or in connection with this Agreement.

19.9  Neither party may sell, transfer or assign any right, duty or obligation
granted or imposed upon it under this Agreement without the prior written
consent of the other party, which consent shall not be unreasonably withhold or
delayed. Notwithstanding anything to the contrary in this Agreement either party
shall have the right to assign this Agreement, in whole or in part to any
affiliate or to any entity who is not a direct competitor of Unisphere Solutions
Inc, where such affiliate or entity purchases or succeeds to substantially all
of the assets of the business to which this Agreement relates, effective upon
written notice to the other party. The assigning party shall provide the other
party with prior, to the maximum extent possible, written notice of such
assignment

19.10 The parties agree that transmission of data by EDI (electronic data
interchange) will not occur until a separate agreement governing such
transmissions is executed. Upon execution, such EDI agreement will become an
attachment to this Agreement

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   17

EXECUTION VERSION                      17

19.11 Neither party shall be liable for damages and costs to the other party
arising out of delays or failures to perform under this Agreement if such delays
or failures result from causes beyond the reasonable control of a party, and are
not caused by an act or omission of such party. Notice of any such delays or
failures and explanation of their causes must be given to the other party within
two (2) days of the occurrence. As soon as it is reasonably apparent that the
occurrence will likely cause a delay of more than thirty (30) days, the party
against whom this section is invoked shall have the right to terminate the
affected installments under any Purchase Order. This force majeure provision may
not be invoked for failure or inability to make a payment under this Agreement.

19.12 CNI is the only entity authorized to purchase Product hereunder and BULL
is the only entity authorized to manufacture hereunder. The individuals
executing this Agreement certify they have the legal authority to bind that
entity. Any affiliates, subsidiaries, and permitted assigns ("Assignees") of CNI
which CNI wishes to purchase Product hereunder must execute a copy of this
Agreement and CNI warrants that any and all obligations and debts of the
Assignees will be discharged in a timely fashion.

19.13 This Agreement and performance by BULL and CNI under it shall be governed
by the laws of the Commonwealth of Massachusetts.

19.14 Both parties pledge their full cooperation and good faith to settle any
differences under this Agreement in a reasonable, business-like and commercial
manner. However, in the event any difference can not be so settled, both parties
shall submit the dispute to binding arbitration. The arbitration shall be
conducted in accordance with the commercial dispute rules of the American
Arbitration Association. The Arbitration shall occur in Boston or as otherwise
agreed; provided, however, that the arbitrators may from time to time convene,
carry on hearings, inspect property or documents, and take evidence at any
location which they deem appropriate. The arbitration shall be held before a
panel of three arbitrators, one selected by each party and the third (who shall
preside) selected by the first two. The arbitrators shall be well-versed in any
technology related to the subject matter of the dispute and have sole and
complete discretion to decide the scope of any permitted discovery and to
resolve any other disputes concerning the arbitration but may not limit, expand
or otherwise modify the term of this Agreement and shall be bound by the
limitations on liability contained herein. The arbitrators' award may in
appropriate circumstances (other than in disputes concerning patents or other
Proprietary Rights) provide for injunctive or other equitable relief. Judgment
upon the decision rendered by the arbitrators may be entered in any court having
jurisdiction. The institution and maintenance of an action for Injunction or
other equitable relief or pursuit of a provisional or ancillary remedy shall not
constitute a waiver of the right of any party, including the plaintiff, to
submit the controversy or claim to arbitration if any other party contests such
action for judicial relief. The remedies under this Agreement shall be
cumulative and not exclusive, and election of one remedy shall not preclude
pursuit of other remedies.

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   18

EXECUTION VERSION                      18

IN WITNESS WHEREOF, each party represents that it has caused this Agreement to
be executed on its behalf on the date first above written (Effective Date) by a
representative empowered to bind that party with respect to the undertakings and
obligations contained herein.

CASTLE NETWORKS, INC.                    BULL NH INFORMATION SYSTEMS INC.,
                                         ACTING THROUGH ITS BULL ELECTRONICS
                                         DIVISION

By: /s/ Stephen J. Maffeo                By: /s/ Robert J. McCarthy
    --------------------------------         -----------------------------------
Printed Name: Stephen J. Maffeo          Printed Name: Robert J. McCarthy
              ----------------------                  --------------------------
Title: CFO                               Title: VP Sales & Marketing
       -----------------------------            --------------------------------

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   19

EXECUTION VERSION                      19

                                   SCHEDULE 1

                        PRODUCT SPECIFICATION AND PRICING

                                 (SEE ATTACHED)

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   20

EXECUTION VERSION                      20

Confidential Materials are omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

<TABLE>
<CAPTION>

------------------------------------------------------- ---------------------------------------------------
                                                        BULL ELECTRONICS
FY99-00 CASTLE NETWORKS PRICING                         WORLDWIDE MANUFACTURING SERVICES
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
                                        Q3 1999                    Q4 1999                     Q1 2000
                               Q3      Production         Q4      Production       FY00       Production
   Board No. Description       Qty       Cost*            Qty       Cost*         Q1 Qty        Cost**
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
<S>                            <C>       <C>              <C>       <C>         <C>
        17-00000-00            100       $[**]            100       $[**]
       Shelf Cntrlr
         Rev. 3.4                                                               Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00001-00            300       $[**]            300       $[**]
    DXM (formerly DS3)
         Rev. 3.3                                                               Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00002-00
      Call Processor           100       $[**]            100       $[**]
         Rev. 2.7                                                               Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
       17-00004-000
      Shelf Cntrlr IO          100       $[**]            100       $[**]
         Rev. 2.0                                                               Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00006-00
          DXM IO
    (formerly DS3# IO)         300       $[**]            300       $[**]
         Rev. 2.2
      Multiples of 2                                                            Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00006-00
     DS# Redundant CCA
         Rev. 2.0               85       $[**]             85       $[**]
      Multiples of 2
   Min order of 6 months                                                        Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00007-00            100       $[**]            100       $[**]
         Rev. 1.10                                                              Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00009-00             54       $[**]             54       $[**]
        Fan Cntrlr
         Rev. 2.0
      Multiples of 4
   Min order of 6 months                                                        Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00010-00             25       $[**]            180       $[**]
            CXM                                                                 Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00011-00             25       $[**]            180       $[**]
          CXM I/O                                                               Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00012-00
       Term. Card L             50       $[**]             50       $[**]
         Rev. 1.0                                                               Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
        17-00013-00             50       $[**]             50       $[**]
       Term. Card L
         Rev. 1.0                                                               Need Forecast
---------------------------- -------- ------------- --- -------- ------------- ------------- -------------
</TABLE>

*  If actual quantities shipped to CNI during the applicable calendar quarter
   are different than the quantities set forth above, Bull reserves the right to
   requote the unit price to CNI based on actual quantities to be shipped.

** Q1 200 Production Cost shall depend on actual quantities shopped during Q1
   2000. If actual quantities shipped during Q1 2000 are at least equal to the
   quantities shown in Q4 above upon which Q4 1999 Production Costs are based,
   then Q1 2000 Production Cost shall be at least equal to such Q4 1999
   Production Cost.

-  Standard assembly lead time is 2-3 weeks. Add 1 additional week for flying
   probe test. Any delivers requested inside of these standard lead times will
   be quoted based individually base on capacity lead time. Lead times will
   have a quick turn surcharge assessed.

-  Note -- Bull Electronics to procure materials and assemble quarterly.
   Finished shipments will be made monthly in lots designated by Castle
   Networks.

    PRODUCT SPECIFICATION PRICING ATTACHMENT AS SCHEDULE 1 OF THE CASTLE/BULL
                               PURCHASE AGREEMENT

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   21

EXECUTION VERSION                      21

                                   SCHEDULE 2

                        SUBCONTRACT QUALITY REQUIREMENTS

BULL shall be responsible for the following quality requirements:

-     Successful submission of a Quality Survey.
-     Follow CNI Workmanship Standards as they become available.
-     Ionic cleanliness testing is required per Bellcore TR-NWT-000078.
-     Product is to be built per assembly drawings, BOM's and ECO's. Exceptions
      must be approved, in writing.
-     Utilization of CNI Approved Vendor Listings, without exception, unless a
      documented waiver exists.
-     Maintain ISO9001 registration.
-     Maintain BABT production quality assurance approval, including critical
      component listings and required test processes.
-     Maintain all critical component listings and follow test processes as
      required for UL/CSA/ETL factory approval and audit.
-     BULL is required to provide the following reports to CNI on a monthly
      basis:
      -     Factory Yields, including assembly and test.
-     On new product/pilot runs, provide a written report on any design for
      manufacturability/testability issues encountered with the build of the
      product.
-     CNI reserves the right to audit BULL's manufacturing and quality processes
      and procedures and to conduct periodic source inspection at BULL's
      facility.

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   22

EXECUTION VERSION                      22

                                   SCHEDULE 3

                           APPROVED VENDOR LIST (AVL)

An electronic copy of the AVL will be maintained by CNI and provided to Bull.

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   23

EXECUTION VERSION                      23

                                   SCHEDULE 4

                           TEST PROGRAMS AND FIXTURES

CASTLE NETWORKS TEST NRE                                                 9/15/99

PART NUMBER              ETCH REV PROBE       ICT FIXT          ICT PROG
17-00000-000                 3Y               Y                 Y
17-00001-000                 3Y               Y                 Y
17-00002-000                 2Y               Y                 Y
17-00004-000                 2N               Y                 Y
17-00005-000                 2N               Y                 Y
17-00006-000                 2N               N                 Y
17-00007-000                 1N               Y                 Y
17-00008-000                 na               na                na
17-00009-000                 2N               N                 Y
17-00010-000                 2Y               N                 N
17-00011-000                 1Y               N                 N
17-00012-000                 1Y               Y                 Y
17-00013-000                 1Y               Y                 Y

Note:  Some card share same fixture.

CASTLE NETWORKS, INC.                                       COMPANY CONFIDENTIAL

<PAGE>   24

                                   ASSIGNMENT

This Assignment is made effective as of the         day of December, 1999 (the
"Effective Date") by and among Unisphere Solutions, Inc., One Executive Drive,
Chelmsford, Massachusetts 01824 ("Unisphere"), Castle Networks, Inc. Agreement,
One Executive Drive, Chelmsford, Massachusetts 01824 ("CNI") and Bull HN
Information Systems Inc., 1001 Pawtucket Blvd., Lowell, Massachusetts 01854
("Bull").

Whereas, CNI and Bull entered into a Master Manufacturing and Purchase
Agreement dated September 22, 1999 (the "Agreement");

Whereas, subsequent to entering into the Agreement, CNI desires to have all
purchase orders issued by, and all invoices issued to, its affiliate Unisphere,
as part of an assignment by CNI of all of CNI's right, title and interest under
the Agreement to Unisphere, and under the terms of the Agreement, in order to
effectuate such an assignment, the written consent of Bull is required;

Whereas, Bull is willing to accept such assignment on the terms and conditions
set forth herein, subject to Unisphere agreeing to the terms and conditions of
such assignment, as set forth herein;

Now therefore, in consideration of the foregoing mutual premises and promises
hereinafter set forth, the parties agree as follows:

1. As of the Effective Date, CNI hereby assigns to Unisphere, and Unisphere
hereby assumes all rights and obligations of CNI in the Agreement, including,
without limitation, that any and all purchase orders and other liabilities
originally issued and/or incurred by CNI under the Agreement as of the
Effective Date shall be assigned to Unisphere.

2. As of the Effective Date, Unisphere accepts the assignment of the Agreement
as set forth in Section 1 and hereby assumes all rights and obligations in the
Agreement, including, without limitation, (a) all rights under any and all
purchase orders outstanding as of the Effective Date and any and all invoices
issued originally to CNI as of the Effective Date, in each case, to the extent
such purchase orders have been issued and invoices sent to CNI under the
Agreement and (b) all rights and obligations that may arise after the Effective
Date to the extent that Unisphere issues purchase orders or otherwise desires
Bull to manufacture Products or provide any of the services described in the
Agreement.

3. Subject to the assignment and as set forth in Section 1 and the acceptance
of such assignment as set forth in Section 2, Bull hereby consents to the
assignment of the Agreement from CNI to Unisphere.

4. Except as expressly amended hereby, all of the terms and conditions of the
Agreement shall remain in full force and effect except that any reference in
the Agreement to CNI shall instead be deemed to be a reference to Unisphere.

IN WITNESS WHEREOF, the parties have caused their duly authorized
representatives to have executed this Assignment of the Effective Date.

UNISPHERE SOLUTIONS, INC.                    CASTLE NETWORKS, INC.
By: /s/ Stephen J. Maffeo                    By: /s/ Stephen J. Maffeo
   ------------------------------               -----------------------------
Printed Name:                                Printed Name: Stephen J. Maffeo
             --------------------                         -------------------
Title:                                       Title: CFO Castle Networks
      ---------------------------                  --------------------------

                  BULL HN INFORMATION SYSTEMS INC.,
                  ACTING THROUGH ITS BULL ELECTRONICS DIVISION

                  By: /s/ Robert J. McCarthy
                     -------------------------------------
                  Printed Name: Robert J. McCarthy
                               ---------------------------
                  Title: V.P. Sales & Mktg.
                        ----------------------------------

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