Document:

EXHIBIT 10.10

           CONFIDENTIAL MATERIALS HAVE BEEN OMITTED FROM THIS EXHIBIT
         PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT AND HAVE BEEN
          FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION.
                           ASTERISKS DENOTE OMISSIONS.

                                MASTER AGREEMENT

                                 BY AND BETWEEN

                             WINSTAR WIRELESS, INC.

                                       AND

                        SAVVIS COMMUNICATIONS CORPORATION

This  Master  Agreement  is entered  into as of the 30TH day of June,  2000 (the
"Effective Date") by and between WINSTAR WIRELESS, INC., a Delaware corporation,
with offices located at 7799 Leesburg Pike, Suite 700 South,  Tysons Corner,  VA
22043  ("Winstar"),   and  SAVVIS  COMMUNICATIONS   CORPORATION,  a  corporation
organized  under the laws of Missouri,  with offices  located at 12851 Worldgate
Drive, Herndon, VA 20170 ("Customer").

                              EXPLANATORY STATEMENT

Winstar  operates a  telecommunications  network  between  various points in the
United States.  Customer  desires to acquire from Winstar certain  equipment and
associated  connectivity.  Winstar  is willing  to  provide  Customer  with such
equipment and  associated  connectivity  on the terms and  conditions  set forth
herein.

                              TERMS AND CONDITIONS

1.    DEFINITIONS

      1.1 CERTAIN DEFINITIONS.

          (a)  "Affiliate"  shall mean,  with  respect to any entity,  any other
entity  Controlling,  Controlled  by or under  common  Control with such entity,
whether directly or indirectly through one or more intermediaries.

          (b) "Agreement" means this Master Agreement.

          (c) "Business Day" means any day on which  Citibank,  N.A. is open for
the transaction of banking business.

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          (d) "Connectivity" shall mean the use of telecommunication  facilities
and equipment necessary to achieve one or more desired connections.

          (e)  "Control"  and its  derivatives  shall mean legal,  beneficial or
equitable ownership, directly or indirectly, of more than fifty percent (50%) of
the  outstanding  voting capital stock (or other  ownership  interest,  if not a
corporation) of an entity, or actual managerial or operational control over such
entity.

          (f)  "Days"  or "days"  shall  mean  calendar  days  unless  otherwise
specified.

          (g) "Effective Date" has the meaning set forth in the preamble to this
Agreement.

          (h) "Eligible  Location" shall mean a building  designated by Customer
that has been approved by Winstar for purposes of installing the Equipment.

          (i) "End User" shall mean the person or entity to whom Customer  sells
the Equipment, or if the Equipment is used by Customer, Customer.

          (j)  "Equipment"  shall  mean the  equipment  provided  by  Winstar to
Customer pursuant to Exhibit A.

          (k)  "Events of  Default"  shall mean each of the  following:  (i) any
representation  or warranty made by a Party in the  Transaction  Documents which
was incorrect in any respect when made and that could  reasonably be expected to
have a material  adverse  effect upon the other  Party's  ability to realize the
benefits of the Transaction Documents; (ii) a material breach of the Transaction
Documents that is capable of being cured on commercially reasonable terms within
thirty (30) days, which breach is not cured within thirty (30) days after notice
of breach to the breaching  Party, or (iii) a material breach of the Transaction
Documents  that is not  capable of being cured  within  thirty (30) days and the
breaching  Party fails to (a) proceed  promptly  and  diligently  after  written
notice to correct the breach,  (b) develop  within  fifteen (15) days  following
written notice of breach a complete plan for curing the breach, and (c) cure the
breach within sixty (60) days of notice thereof.

          (l) "FCC Licenses" shall have the meaning set forth in Section 5.3.

          (m) "FCC" shall mean the Federal Communications Commission.

          (n) "Link  Availability  Letter"  means a letter signed by Winstar and
delivered  to  Customer  which  advises  Customer  that the  Link has been  made
available for Customer's use at the designated location(s).

          (o) "Link" shall mean a radio spectrum path on a  line-of-sight  basis
between  radio pairs,  one radio which is located at a Winstar hub and the other
of which is located at an Eligible Location, and the related backhaul facilities
connecting  the Winstar hub to a Winstar  switch center as set forth in Schedule
B-1 to Exhibit B.

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          (p)  "Local   Connectivity"   shall   mean   wireless   local   access
Connectivity.

          (q) "Losses" shall mean all liabilities, damages and related costs and
expenses  (including  fines,  levies,  assessments,  reasonable  legal  fees and
disbursements and costs of  investigations,  litigation,  settlement,  judgment,
interest and penalties) directly incurred by a Party.

          (r) "Parties" shall mean Customer and Winstar, together.

          (s)  "Party"  shall  mean  Customer  or  Winstar,   individually,   as
appropriate.

          (t) "POP" shall mean the Winstar terminal facility (point of presence)
where the Links are delivered to Customer.

          (u)  "Purchase  Price"  shall  mean the  aggregate  sum of all  monies
required  to be  paid  by  Customer  to  Winstar  pursuant  to  the  Transaction
Documents.

          (v) "Spectrum"  shall mean certain  licensed radio  frequency  network
capable of fiber quality transmissions.

          (w) "Term" shall have the meaning set forth in Section 3.

          (x) "Transaction  Documents" shall mean the Agreement and all Exhibits
and Schedules thereto.

          (y)    "Winstar    Network"    shall    mean   the    facilities-based
telecommunications system over which Winstar offers telecommunications services.

      1.2 OTHER  DEFINITIONS.  Other terms used in this Agreement are defined in
the  context in which they are used and have the  meanings  there  stated or are
defined in the applicable Transaction Document.

2.  REGULATORY  ISSUES.  Customer  shall not take a  position  or issue a public
statement  with  respect  to  regulatory  or  legislative  issues  that could be
reasonably  expected to impact Winstar's  business without first consulting with
Winstar.  In general,  the Parties agree to affirmatively take a position in the
United States  regulatory  environment  in favor of a level playing field and in
support of competition. Customer shall, at Winstar's expense, assist and support
in good faith all of Winstar's  regulatory-related  efforts in  connection  with
obtaining required licenses, approvals or otherwise in connection with Winstar's
obligations hereunder.

3.  TERM.  Except  as  may  otherwise  be  provided  therein,  the  term  of the
Transaction  Documents shall begin upon the Effective Date and shall end on that
date which is the later of (a) the tenth  (10th)  anniversary  of the  Effective
Date or (b) the term stated in any  Schedule  or Exhibit  (the  "Term"),  unless
terminated earlier in accordance with this Agreement.

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4. OBLIGATIONS OF THE PARTIES

      4.1 EQUIPMENT  SALE.  Winstar shall sell to Customer,  and Customer  shall
purchase from Winstar,  the  Equipment,  pursuant to the terms and conditions in
Exhibit A.

      4.2 INSTALLATION SERVICES. Winstar shall provide to Customer, and Customer
shall purchase from Winstar, installation services for the Equipment pursuant to
the terms and conditions in Exhibit B.

      4.3 LOCAL  CONNECTIVITY AND BACKHAUL  TRANSPORT.  Winstar shall provide to
Customer, and Customer shall purchase from Winstar,  wireless Local Connectivity
and Backhaul transport pursuant to the terms and conditions of Exhibit C.

      4.4  OPERATION  AND  MAINTENANCE  OF  EQUIPMENT.  Winstar shall provide to
Customer and Customer shall purchase from Winstar the operation and  maintenance
services  with respect to the Equipment on similar terms as set forth in Exhibit
D.

      4.5  COLLOCATION.  Pursuant to the terms and  conditions  of the  Terminal
Facility Collocation Space Exhibit attached as Exhibit E, Winstar shall lease to
Customer, and Customer shall lease from Winstar, space in certain premises.

5. COVENANTS OF THE PARTIES.

      5.1 NETWORK INTEGRITY.

          5.1.1  Customer  may not  improperly  restrict or  interfere  with the
Winstar  Network or the use  thereof.  Upon  notice by Winstar,  Customer  shall
promptly  remove any hazard,  interference  or service  obstruction  that may be
caused by hardware,  software or connectivity,  owned by or under the control of
Customer.  Nothing stated herein shall be construed to interfere with Customer's
ability to comply with the rules,  regulations or directives of any governmental
or jurisdictional authority.

          5.1.2 In the event that  Customer  improperly  restricts or interferes
with the Winstar Network or the use thereof,  Winstar may, after giving Customer
notice,  immediately modify, suspend, delay, condition, or cease until cured its
obligations under the Transaction Documents in whole or in part.

      5.2 ACCESS TO FACILITIES. Each Party shall, upon the reasonable request of
the  other  Party,  provide  the  other  Party's  personnel  with  access to its
facilities  to the extent  reasonably  required  for such  Party to perform  its
obligations  hereunder.   Any  such  access  permitted  hereunder  shall  be  in
accordance with each Party's applicable  internal security  procedures,  and any
applicable governmental requirements.

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      5.3 CONTROL; LICENSES.

          (a) Except as is agreed to by the Parties in writing,  Customer  shall
secure,  at its own expense,  other than the licenses  held by Winstar for Local
Connectivity pursuant to this Agreement ("FCC Licenses"), all licenses, permits,
agreements,  consents,  rights-of-way, and other arrangements necessary for: (i)
the  installation  of  Customer's  equipment  and  (ii) the  interconnection  of
Customer-provided  terminal equipment or communications systems with the Winstar
Network or other Winstar facilities.  Winstar shall, at Customer's request,  use
all  reasonable  efforts to cooperate  with Customer in meeting its  obligations
under this subparagraph 5.3 (a).

          (b) During the Term,  the Equipment  shall at all times be operated in
compliance  with  all  applicable  FCC  rules  and  regulations  as  well as all
applicable state and local regulations or requirements  governing  Winstar's FCC
Licenses, and the provision of telecommunications services thereunder.

          (c)  Winstar  shall  retain  at all  times  during  the  term  of this
Agreement  control over its FCC  Licenses,  and shall have, at all times therein
unfettered access to the Equipment and all of the facilities where transmissions
and receptions under its FCC Licenses are being conducted.

          (d) Winstar  will take all  reasonable  precautions  not to disturb or
interfere  with  Customer's  services or property,  unless such  disturbance  or
interference  is deemed by Winstar to be necessary for control of the use of the
FCC  Licenses,  such as  execution  of a  request  from  the  FCC to  shut  down
interfering  transmissions or performing emergency service restoration.  Winstar
shall provide Customer with notice of any such disturbance or interference.

          (e) During the Term, Customer shall not represent itself as the holder
of any of the FCC Licenses, nor as the representative of Winstar before the FCC,
any state regulatory body or any other third party.

          (f) Except as  otherwise  required by law, all filings made during the
Term of this Agreement  before  regulatory  bodies with respect to Winstar's FCC
Licenses  shall  be  made by and in the  name of  Winstar,  and  Customer  shall
cooperate fully with Winstar in the making of such filings.

          (g)  Nothing in this  Agreement  is  intended  to diminish or restrict
Winstar's  compliance with its obligations  before the FCC. Winstar and Customer
desire that this Agreement and the  obligations  performed  hereunder be in full
compliance with (i) the terms and conditions of Winstar's FCC Licenses; (ii) all
applicable rules and policies of the FCC; (iii) the  Communications Act of 1934,
as  amended,  and (iv) any  other  applicable  federal,  state  and local law or
regulation.  If the FCC or any state body of competent  jurisdiction  determines
that any provision of this Agreement violates any

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applicable rules,  policies, or regulations,  both Parties shall make reasonable
efforts to immediately bring this Agreement into compliance, consistent with the
terms of this Agreement. It is expressly understood by Winstar and Customer that
nothing in this  Agreement is intended to give Customer any right which would be
deemed to  constitute  a transfer  of control  (as  `control'  is defined in the
Communications Act of 1934, as amended,  and/or any applicable FCC rules or case
law) by Winstar of one or more of the FCC Licenses from Winstar to Customer.

6. PAYMENT TERMS

      6.1 TRANSFER OF EQUIPMENT.  As of the Effective  Date,  Customer agrees to
purchase  the  Equipment  and  related  services  pursuant  to  the  Transaction
Documents and Winstar agrees to transfer the Equipment in consideration  for the
price set forth in Exhibit A.

      6.2  PAYMENT OF PURCHASE  PRICE.  The  Purchase  Price shall be payable in
accordance with the payment terms set forth in the Exhibits  attached hereto. In
the event that  Customer  elects to pay any  component of the Purchase  Price in
accordance with any such options in any Exhibits  attached hereto,  that portion
of the  deferred  Purchase  Price shall be secured  pursuant to Schedule  M-6.2.
Customer   shall  make  payments  under  this  Agreement  by  wire  transfer  of
immediately  available funds to the United States account or accounts designated
by the payee.  At the payee's  discretion,  payments to be made pursuant to this
Agreement may be made by check or draft of immediately available funds delivered
to the address  designated in writing by the payee or, failing such designation,
to the address for notice to payee pursuant to Section 13.2. Except as expressly
provided  otherwise,  the Purchase Price will be the sole  consideration  due to
Winstar  for the  performance  of any and all of its  obligations  due under the
Transaction Documents.

      6.3 ALLOCATION.  The Parties agree to allocate the Purchase Price (and all
other  capitalizable  costs)  between  and  among  the  Equipment  listed on the
allocation  table  attached as Schedule  M-6.3 for all purposes  (including  for
accounting  and  tax  purposes).  Winstar  and  Customer  agree  to  report  the
allocation as provided in the applicable  sections of the Internal  Revenue Code
of 1986, as amended, and regulations promulgated thereunder,  in accordance with
such allocation and agree to prepare and file all income tax returns in a manner
consistent with such allocation.

      6.4 TAXES.  The Parties'  respective  responsibilities  for taxes  arising
under or in connection with the Transaction Documents shall be as follows:

          (a) Each Party shall be  responsible  for personal  property  taxes on
property it owns or leases,  for franchise and privilege  taxes on its business,
for taxes  based on its net income or gross  receipts,  and for any  third-party
imposed fees.

          (b) Each Party  shall  timely  report and pay any and all sales,  use,
income, gross receipts, excise, transfer, ad valorem or other taxes, and any and
all

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franchise fees or similar fees assessed against it due to the  implementation of
any facilities or equipment in connection with the Equipment.

          (c) The Parties  agree to cooperate  with each other to enable each to
determine  more  accurately its own tax liability and to minimize such liability
to the extent legally  permissible.  Each Party shall provide and make available
to the  other  any  resale  certificates  and other  exemption  certificates  or
information  reasonably  requested  by either  Party that is  applicable  to the
subject matter of this Agreement.

          (d) Each Party shall within thirty (30) business days notify the other
of,  and  coordinate  the  response  to and  settlement  of, any claim for taxes
directly related to the transactions  contemplated by this Agreement asserted by
applicable  taxing   authorities  for  which  the  other  Party  is  responsible
hereunder. With respect to any claim arising out of a form or return signed by a
Party to this Agreement, such Party shall have the right to elect to control the
response to and settlement of the claim.

7. CONFIDENTIALITY

The terms and  conditions of that certain non disclosure  agreement  between the
Parties,  a copy of which is appended  hereto as Schedule M-7, are  incorporated
herein by this reference and shall continue in full force and effect  throughout
the Term of this Agreement.

8. TERMINATION.

      8.1  TERMINATION.  In the event  that  either  Party  commits  an Event of
Default,  then the other Party may, by giving  written  notice to the defaulting
Party (i)  terminate  this  Agreement  for cause as of a date  specified  in the
notice of termination, and (ii) subject to the terms of this Section, pursue any
legal remedies it may have under applicable law or principles of equity relating
to  such  breach.  Any  Event  of  Default  may  be  waived  in  writing  at the
non-defaulting Party's option.

      8.2 EFFECT OF  TERMINATION.  Termination of this  Agreement  refers to the
termination of the Parties'  respective  commitments  and  obligations  from and
after the date of termination, but does not relieve the Parties of their payment
and  other  obligations  incurred  prior to the date of  termination  and  their
continuing  obligations  under  Sections  7 and  12 or as  may  be  specifically
provided in any Schedule or Exhibit.

9. REPRESENTATIONS; DISCLAIMER

      9.1 REPRESENTATIONS. Each Party represents and warrants to the other that:

          (a) It has the requisite  corporate  power and authority to enter into
the Transaction Documents and to carry out the transactions  contemplated by the
Transaction Documents; and

          (b)  The  execution,  delivery  and  performance  of  the  Transaction
Documents  and  the  consummation  of  the  transactions   contemplated  by  the
Transaction

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Documents  have been duly  authorized by the requisite  corporate  action on the
part of such Party.

          (c) Each Party  represents  that the  Transaction  Documents have been
duly  executed  and  delivered,  and create  lawful,  valid and legally  binding
obligations,  in  accordance  with their  respective  terms.  The  execution and
delivery of the Transaction  Documents and the  consummation of the transactions
contemplated  hereby are not  prohibited by, do not violate or conflict with any
provision  of,  and do not  constitute  a default  under or a breach of: (a) any
contract,  agreement or other  instrument to which it is a party or by which any
of the assets  that are the  subject  hereof are  bound;  or (b) to the  Party's
knowledge,  any order,  writ,  injunction,  decree or  judgment  of any court or
governmental agency.

          (d) Winstar  represents  that the Network  Facilities will function in
accordance with the Terms of the Transaction Documents for the Term.

      9.2  DISCLAIMER.  EXCEPT  AS  SPECIFICALLY  SET  FORTH IN THE  TRANSACTION
DOCUMENTS,  THE PARTIES  MAKE NO WARRANTY TO EACH OTHER OR TO ANY OTHER  ENTITY,
WHETHER EXPRESS,  IMPLIED OR STATUTORY, AS TO THE MERCHANTABILITY OR FITNESS FOR
ANY  PARTICULAR  PURPOSE  OF THE  EQUIPMENT,  ANY  FACILITIES  PROVIDED  OR USED
HEREUNDER OR DESCRIBED HEREIN, ANY SERVICES,  EQUIPMENT,  MATERIAL,  GOODS, REAL
ESTATE OR OTHER  TANGIBLE OR  INTANGIBLE  ASSET THAT IS CONVEYED,  HYPOTHECATED,
LEASED,  SOLD,  OR  OTHERWISE  PROVIDED TO CUSTOMER IN ANY MANNER,  OR AS TO ANY
OTHER  MATTER,  ALL OF  WHICH  WARRANTIES  ARE  HEREBY  EXPRESSLY  EXCLUDED  AND
DISCLAIMED.

      IN NO EVENT SHALL WINSTAR, ITS AFFILIATES, OFFICERS, DIRECTORS, EMPLOYEES,
AGENTS OR ASSIGNS BE LIABLE FOR ANY DAMAGES,  INCLUDING BUT NOT LIMITED TO, LOST
PROFITS, LOSS OF BUSINESS, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE OR
CONSEQUENTIAL  DAMAGES THAT RESULT IN ANY WAY FROM  CUSTOMER'S OR ITS AUTHORIZED
USERS'  RELIANCE ON OR USE OF  CONTENT,  INFORMATION,  SERVICES  OR  MERCHANDISE
PROVIDED ON OR THROUGH THE DATA SERVICES, OR THAT RESULT FROM OR ARE RELATED TO,
MISTAKES, OMISSIONS,  INTERRUPTIONS,  DELETION OF FILES, ERRORS, DEFECTS, DELAYS
IN OPERATION OR  TRANSMISSION OR ANY FAILURE OF PERFORMANCE OF ANY KIND, EVEN IF
WINSTAR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

10. LIABILITY

      10.1 GENERAL  INTENT.  Subject to the specific  provisions of this Section
10, it is the intent of the Parties that each Party shall be liable to the other
Party only for any  direct  damages  incurred  by the  non-breaching  Party as a
result of the breaching Party's failure to perform its obligations in the manner
required by the Transaction Documents.

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     10.2 LIABILITY RESTRICTIONS.

          (a) Each Party's liability to the other whether in contract or in tort
(including breach of warranty, negligence and strict liability in tort) shall be
limited to the amounts  actually paid (including both principal and interest) to
Winstar by Customer at the time the event resulting in liability occurs.

          (b) The limitation set forth in Subsection (a), above, shall not apply
with respect to: (i) third-party claims subject to  indemnification  pursuant to
the  Agreement;  or (ii) fees due and owing under this  Agreement at the time of
the claim.

          (c) For the purposes of this Section 10.2, all amounts payable or paid
to third parties in connection with claims that are eligible for indemnification
pursuant to this Agreement shall be deemed direct damages.

     10.3 FORCE MAJEURE.

          (a)  Neither  Party  shall be liable  for any  default or delay in the
performance of its  obligations  under the  Transaction  Documents if and to the
extent  such  default  or delay is  caused,  directly  or  indirectly,  by fire,
explosion,  vandalism, power outage, flood, lightning,  earthquake,  elements of
nature  or "acts of God",  war,  riots,  any  civil or  military  authority  (by
national  emergency  or acts of third  parties),  civil  disorders,  rebellions,
revolutions,  insurrections, or acts of terrorism, provided that such default or
delay could not have been prevented by reasonable  precautions by the Party with
the  obligation  to perform and cannot be reasonably  circumvented  by the Party
with the obligation to perform through the use of alternate sources,  workaround
plans or other means.

          (b) In such event,  the Party with the  obligation to perform shall be
excused from further  performance or observance of the obligation(s) so affected
for as long as such  circumstances  prevail  and  such  Party  continues  to use
commercially reasonable efforts to recommence performance or observance whenever
and to whatever extent possible without delay.

11. INDEMNIFICATION

     11.1 INDEMNITIES BY WINSTAR.  Winstar agrees to indemnify,  defend and hold
harmless Customer and its Affiliates and their respective  officers,  directors,
employees, managers, contractors,  agents, successors, and assigns, from any and
all Losses and  threatened  Losses,  arising  from,  relating  to,  incurred  in
connection with, or based on allegations of, any of the following:

          (a) Any claims of  infringement  or  misappropriation  of any  patent,
trade secret,  copyright or other proprietary  rights,  alleged to have occurred
based upon the provision of the Equipment by Winstar,  except to the extent that
such  claims  arise from (i)  modification  of the  Equipment  or any  component
thereof by Customer that is not  recommended  or otherwise  approved by Winstar,
(ii) use of the Equipment by

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Customer in combination with deliverables furnished by third parties that is not
recommended or otherwise approved by Winstar;

          (b) To the extent caused by Winstar, the death or bodily injury of any
agent,  employee,  customer,  business invitee or any other person caused by the
tortious conduct of Winstar;

          (c) To the extent caused by Winstar,  the damage,  loss or destruction
of any real or tangible  personal  property  caused by the  tortious  conduct of
Winstar; or

          (d) To the  extent  caused by  Winstar,  any  claim,  demand,  charge,
action,  cause of action,  or other  proceeding  asserted  against  Customer but
resulting from an act or omission of Winstar in its capacity as an employer of a
person.

     11.2 INDEMNITIES BY CUSTOMER. Customer agrees to indemnify, defend and hold
harmless  Winstar and its Affiliates and their respective  officers,  directors,
employees, managers, contractors,  agents, successors, and assigns, from any and
all  Losses and  threatened  Losses  arising  from,  relating  to,  incurred  in
connection with, or based on allegations of, any of the following:

          (a) Any claims of  infringement  or  misappropriation  of any  patent,
trade secret,  copyright or other proprietary  rights,  alleged to have occurred
based upon misuse of the Equipment by Customer,  including (i)  modification  of
the Equipment or any component  thereof by Customer that is not  recommended  or
otherwise  approved  by  Winstar,  or (ii) use of the  Equipment  by Customer in
combination   with   deliverables   furnished  by  third  parties  that  is  not
contemplated by the Transaction Documents,  recommended or otherwise approved by
Winstar;

          (b) The  death or  bodily  injury of any  agent,  employee,  customer,
business invitee or any other person caused by the tortious conduct of Customer;

          (c) The damage,  loss or destruction of any real or tangible  personal
property caused by the tortious conduct of Customer; or

          (d) Any claim,  demand,  charge,  action,  cause of  action,  or other
proceeding  asserted  against  Winstar but resulting  from an act or omission of
Customer in its capacity as an employer of a person.

12.  DISPUTE  RESOLUTION  Any  dispute  between  the  Parties  arising out of or
relating to the Transaction  Documents,  the  interpretation  of any performance
thereof,  or the performance or failure to perform shall be resolved as provided
in this Section.

     12.1 INFORMAL DISPUTE RESOLUTION.

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          (a) Prior to the initiation of formal dispute  resolution  procedures,
the Parties shall first attempt to resolve their dispute informally  pursuant to
this Section.  Upon the written  request of a Party,  each Party shall appoint a
representative  from its executive  management whose task it will be to meet for
the purpose of endeavoring  to resolve such dispute.  If, after thirty (30) days
from the  appointment of such  representatives  from executive  management,  the
representatives  have not resolved such dispute,  then the provisions of Section
12.2 shall apply.

          (b) The Parties agree that disputes,  controversies  or claims between
them shall not be subject to the provisions of this Section where:

              (i) A Party makes a good faith  determination that a breach of the
terms of the  Transaction  Documents by the other Party is such that a temporary
restraining  order or  other  injunctive  relief  is the  only  appropriate  and
adequate remedy; or

              (ii) Institution of formal  proceedings  earlier than as set forth
in this Section 12.1 for the resolution of a dispute may be commenced  after the
earlier of (x) a good faith determination that such proceedings are necessary to
avoid the expiration of any applicable  limitations  period or (y) to preserve a
superior position with respect to other creditors.

          (c) If a  Party  files  a  pleading  with a  court  seeking  immediate
injunctive  relief and this  pleading is  challenged  by the other Party and the
injunctive  relief sought is not awarded in  substantial  part, the Party filing
the pleading seeking immediate  injunctive relief shall pay all of the costs and
attorneys' fees of the Party successfully challenging the pleading.

         12.2     ARBITRATION.

          (a) Except as provided in Section 12.1(b), any dispute, controversy or
claim  arising out of or relating to the  Transaction  Documents  or the breach,
termination or validity thereof, shall be finally settled in accordance with the
commercial arbitration rules of the American Arbitration Association (the "AAA")
then obtaining, by a panel of three arbitrators.  Judgment upon the award of the
Arbitrators  may be  entered  by any court of  competent  jurisdiction  over the
Parties on the subject matter of the Agreement.  Each party shall have the right
to appoint one arbitrator  from the list of arbitrators  supplied to the parties
by the AAA, and the two arbitrators so appointed shall appoint the third.

          (b) The place of arbitration  shall be the City of New York, New York,
U.S.A.  The language of the  arbitration  shall be in English.  The  arbitrators
shall  determine the matters in dispute in  accordance  with the internal law of
the State of New York,  without reference to the Convention on Contracts for the
International  Sale  of  Goods.  Except  as  precluded  by  the  United  Nations
Convention on the Recognition and Enforcements of Foreign  Arbitral Awards,  the
internal procedural and substantive laws

                                       11
<PAGE>

of New York and the  United  States  Federal  Arbitration  Act shall  govern all
questions of arbitral procedure,  arbitral review,  scope of arbitral authority,
and arbitral enforcement.

          (c) If any necessary  party to the  arbitration  proceeding  cannot be
made a party to the  arbitration,  and a proceeding  is instituted in a court of
competent jurisdiction which results in either (i) either Party having to defend
both the  arbitration and judicial  proceeding or (ii) the arbitrator  having to
adjudicate  a set of facts  identical to the  judicial  proceeding,  then either
Party may at its option elect not to arbitrate, but litigate the issues.

          (d) The parties agree that the award of the  arbitrators  shall be the
sole and exclusive  remedy  between them  regarding  any claims,  counterclaims,
issues or accountings presented or pled to the arbitrators, that the award shall
be made  and  shall  be  promptly  payable  in U.S.  dollars,  free of any  tax,
deduction or offset,  and that any costs, fees or taxes instant to enforcing the
award shall,  to the maximum  extent  permitted  by law, be charged  against the
party resisting such enforcement.

          (e) The award shall include interest from the date of damages incurred
for breach or other violation of the Transaction Documents, and from the date of
the award until paid in full, at a rate to be fixed by the arbitrators.

          (f) No claim may be submitted by a party to  arbitration in accordance
with this  Section 12 unless  notified to the other party within one (1) year of
the date on which the  submitting  party  first knew or should have known of the
existence of the facts indicating the existence of such dispute.

     12.3 CONTINUED  PERFORMANCE.  Each Party agrees to continue  performing its
obligations under the Transaction  Documents while any dispute is being resolved
except to the extent the issue in dispute  precludes  performance  (dispute over
payment shall not be deemed to preclude performance).

13. GENERAL

     13.1 BINDING NATURE AND ASSIGNMENT.

          (a) The  Transaction  Documents  shall accrue to the benefit of and be
binding upon the Parties  hereto and any purchaser or any successor  entity into
which either Party has been merged or  consolidated or to which either Party has
sold or transferred all or substantially all of its assets.

          (b) Except as expressly  provided in a Transaction  Document,  neither
Party may,  or shall  have the power to,  assign the  Transaction  Documents  or
delegate such Party's obligations hereunder without the prior written consent of
the other,  except that either Party may assign its rights and obligations under
the Transaction Documents without the approval of the other Party to

              (i) an  entity  which  acquires  all or  substantially  all of the
assets of the assigning party,

                                       12
<PAGE>

              (ii) to any  Affiliate,  in which event the assignor  shall remain
liable as a guarantor of the  assignee/Affiliate's  performance  of such Party's
obligations hereunder,

              (iii) to a successor in a merger or acquisition, or

              (iv) in the case of Customer,  to any  successor  Affiliate in the
course of the spin-off or other reorganization transaction of Customer.

     13.2 NOTICES. Any notices, requests, demands, and determinations under this
Agreement (other than routine operational  communications),  shall be in writing
and shall be deemed duly given (i) when delivered by hand, (ii) one (1) business
day after being given to an express,  overnight  courier with a reliable  system
for  tracking  delivery,  (iii)  when sent by  confirmed  facsimile  with a copy
delivered  by another  means  specified in this  Section,  or (iv) on the day an
authorized  employee of the  receiving  party accepts  receipt in writing,  when
mailed by United  States mail,  registered  or certified  mail,  return  receipt
requested, postage prepaid, and addressed as follows:

If to Customer:                            If to Winstar:

SAVVIS Communications Corporation          Winstar Wireless, Inc.
12851 Worldgate Drive                      7799 Leesburg Pike
Herndon, VA  20170                         Suite 700 South
ATTN:  MATTHEW A. FANNING                  Tysons Corner, VA  22043
       EXECUTIVE VICE PRESIDENT,           ATTN: ROBERT K. MCGUIRE, PRESIDENT
       STRATEGIC DEVELOPMENT/                    AND CHIEF OPERATING OFFICER
       BUSINESS PLANNING                         WINSTAR LARGE ACCOUNTS
       FACSIMILE:  (703) 716-1059                FACSIMILE:  (703) 226-7649

With a copy to:                            With a copy to:

SAVVIS Communications Corporation          Winstar Wireless, Inc.
795 Office Parkway                         7799 Leesburg Pike
2nd Floor                                  Suite 700 South
St. Louis, MO  63141                       Tysons Corner, VA  22043
ATTN:  STEVEN M. GALLANT                   ATTN: COLLEEN R. JONES
       VICE PRESIDENT                            CHIEF COUNSEL
       AND GENERAL COUNSEL                       WINSTAR LARGE ACCOUNTS
       FACSIMILE:  (314) 468-7550                FACSIMILE:  (703) 226-7649

     A  Party  may  from  time  to time  change  its  address  or  designee  for
notification  purposes  by giving  the  other  prior  written  notice of the new
address or designee and the date upon which it will become effective.

                                       13
<PAGE>

     13.3  COUNTERPARTS.  The  Transaction  Documents may be executed in several
counterparts,  all of which taken together shall constitute one single agreement
between the Parties hereto.

     13.4  RELATIONSHIP  OF PARTIES.  Winstar,  in furnishing  the Equipment and
other services hereunder,  is acting as an independent  contractor,  and Winstar
personnel  (including,  without  limitation,  any  subcontractors)  shall not be
considered  or  represented  as employees or agents of Customer.  Winstar is not
otherwise an agent of Customer and has no authority to represent  Customer as to
any  matters.   Winstar  is  solely   responsible   for:  (a)   performing   its
responsibilities under the Transaction Documents,  (b) management and control of
its  personnel;  (c) the  payment  of all  compensation  owed to its  personnel,
including  payment  of   employment-related   taxes,   benefits,   and  worker's
compensation  insurance;  (d) the filing of all required  employment returns and
reports;  and (e) the withholding and payment of all applicable federal,  state,
and local  taxes and other wage or  employment  assessments,  including  but not
limited to income tax, social security tax, and unemployment  insurance premiums
for its personnel.

     13.5 SEVERABILITY AND MODIFICATION.

          (a) In the  event  that any  provision  of the  Transaction  Documents
conflicts with the law under which the Transaction Documents are to be construed
or if any such  provision  is held  invalid  by an  arbitrator  or a court  with
jurisdiction over the Parties,  such provision shall be deemed to be modified to
reflect  as nearly  as  possible  the  original  intentions  of the  Parties  in
accordance with applicable law. The remainder of the Transaction Documents shall
remain in full force and effect.

          (b) In the event that a provision  of any  Underlying  Agreement is in
conflict with this Agreement, the Agreement will be modified to conform with the
provisions of the Underlying Agreement.

          (c) If this Agreement is modified  pursuant to subsection  (a), (b) or
(d) above,  and as a result of such  modification,  either  Party would not have
entered into this Agreement as set out in the Transaction Documents,  then, that
Party may seek to terminate the Transaction Documents. Any such action must have
a good  faith  basis  and the Party  taking  such  action  must  prove  that the
modification,  had it  been  proffered  at the  time  of  the  execution  of the
Agreement, would have caused it not to so execute.

          (d) If the FCC or any state body of competent jurisdiction  determines
that any provision of the Transaction  Documents  violates any applicable rules,
policies,  or  regulations,  both  Parties  shall  make  reasonable  efforts  to
immediately  bring the Transaction  Documents into compliance and shall endeavor
in those efforts to preserve for both Parties the economic benefits as reflected
in the Transaction Documents to the maximum extent possible.

                                       14
<PAGE>

     13.6 CONSENTS AND APPROVAL. Except where expressly provided as being in the
sole discretion of a Party, where agreement, approval,  acceptance,  consent, or
similar  action by either Party is required  under this  Agreement,  such action
shall not be unreasonably delayed or withheld. An approval or consent given by a
Party under this Agreement shall not relieve the other Party from responsibility
for complying with the requirements of the Transaction  Documents,  nor shall it
be construed as a waiver of any rights under the Transaction  Documents,  except
as and to the extent otherwise expressly provided in such approval or consent.

     13.7 WAIVER OF DEFAULT. No waiver or discharge hereof shall be valid unless
in writing and signed by an authorized representative of the Party against which
such  amendment,  waiver,  or  discharge  is sought to be  enforced.  A delay or
omission  by either  Party  hereto  to  exercise  any  right or power  under the
Transaction Documents shall not be construed to be a waiver thereof. A waiver by
either of the Parties of any of the  covenants  to be  performed by the other or
any  breach  thereof  shall not be  construed  to be a waiver of any  succeeding
breach thereof or of any other covenant.

     13.8  CUMULATIVE  REMEDIES.  Except as otherwise  expressly  provided,  all
remedies  provided for in the  Transaction  Documents shall be cumulative and in
addition to and not in lieu of any other  remedies  available to either Party at
law, in equity or otherwise.

     13.9  SURVIVAL.   Any  provision  of  the   Transaction   Documents   which
contemplates   performance  or  observance  subsequent  to  any  termination  or
expiration of the Transaction  Documents (in whole or in part) shall survive any
termination or expiration of the Transaction  Documents (in whole or in part, as
applicable) and continue in full force and effect.

     13.10 PUBLIC DISCLOSURES.  All media releases,  public  announcements,  and
public  disclosures  relating to this  Agreement  or the subject  matter of this
Agreement,  including  promotional  or  marketing  material,  but not  including
announcements  intended  solely for internal  distribution or disclosures to the
extent required to meet legal or regulatory  requirements  beyond the reasonable
control of the disclosing Party,  shall be coordinated with and shall be subject
to approval by each Party prior to release.

     13.11  THIRD  PARTY  BENEFICIARIES.  Except as  otherwise  provided  in the
Transaction  Documents,  the Transaction Documents shall not be deemed to create
any rights in third parties, including suppliers and customers of a Party, or to
create  any  obligations  of a Party to any such third  parties,  or to give any
right to Customer to enforce this Agreement on behalf of a third party.

                                       15
<PAGE>

     13.12 GOVERNING LAW. The Transaction  Documents and performance  under them
shall be governed by and construed in  accordance  with the laws of the State of
New York without  regard to its choice of law  principles  or the  Convention on
Contracts for the International Sale of Goods.

     13.13 AMENDMENT.  The Transaction Documents shall not be modified,  amended
or in any way altered except by an instrument in writing signed by both Parties.

     13.14 INCORPORATION BY REFERENCE AND ORDER OF PRECEDENCE.

          (a)  Any  conflict  among  or  between  the  documents  making  up the
Transaction Documents will be resolved in accordance with the following order of
precedence (in descending order of precedence):

               (i) The Schedules;

              (ii) The Exhibits to the Schedules; and

             (iii) The Agreement.

          (b) In the  event of  conflict  between  the  documents  making up the
Transaction  Documents and the terms and conditions of any purchase order issued
by either Party, the terms of the Transaction Documents shall supersede any such
purchase order.

     13.15 ENTIRE  AGREEMENT.  The Transaction  Documents  constitute the entire
agreement  between  the  Parties  with  respect  to the  subject  matter in this
Agreement,  and supersede all prior  agreements,  whether  written or oral, with
respect to the subject matter contained in this Agreement.

IN WITNESS  WHEREOF,  this  Agreement  has been  executed  and  delivered by the
Undersigned officers, thereunto, duly authorized, as of the Effective Date.

SAVVIS COMMUNICATIONS                        WINSTAR WIRELESS, INC.
CORPORATION

By:     /s/ Matthew A. Fanning               By:   /s/ Robert  K. Maguire
        --------------------------------           ------------------------

Name:   Matthew A. Fanning                 Name:   Robert K. Maguire
        --------------------------------           ------------------------

 Title: Executive Vice                    Title:   President & Chief Operating
        President--Strategic                       Officer of Large Accounts
        Development &
        Business Planning
       ---------------------------------           ------------------------

Date:   June 30, 2000                      Date:   June 30, 2000
        --------------------------------           ------------------------

                                       16
<PAGE>

                                 SCHEDULE M-6.2

                                       TO

                                MASTER AGREEMENT

                               SECURITY AGREEMENT

1. This Security Agreement Schedule  ("Schedule") shall be governed by the terms
and conditions of the Equipment Purchase Agreement ("Agreement") dated as of the
30th day of June, 2000,  between Winstar Wireless,  Inc.  ("Winstar") and SAVVIS
COMMUNICATIONS CORPORATION ("Customer"). Capitalized terms used in this Schedule
that are not defined below shall have the meaning set forth in the Agreement.

2.  Security  Interest.  As collateral  security for all of  Customer's  payment
obligations under the Agreement, Customer hereby grants Winstar a first priority
security  interest in all of the Radios  purchased or to be purchased  under the
Agreement,  to the maximum  extent  permitted  by law (such items of  collateral
being  collectively or individually,  referred to as the  "Security").  Customer
shall, at Winstar's expense, take all commercially reasonable action required by
Winstar to further  evidence  and/or perfect such security  interest,  including
without  limitation  executing and delivering a separate security  agreement and
UCC-1 financing statements.  In the event Winstar exercises its rights set forth
below, Customer shall cooperate in good faith in assisting Winstar.

3.       Remedies upon Default.

     (i) Upon the  occurrence  of any Event of  Default  that has not been cured
Winstar  shall have the right with or without  legal process and with or without
previous notice or demand for performance,  to replevin,  take possession and/or
control of the  Security or any part  thereof (at the same or  different  times)
and, generally,  to exercise any and all rights, of any kind or nature, afforded
to a secured party under the UCC, or other applicable law, or in equity. Without
limiting the  generality of the  foregoing,  Customer  agrees that Winstar shall
have the right upon  nonpayment  of any amounts due pursuant to this  Agreement,
and such  nonpayment  has not been cured,  subject to notice in  paragraph  (ii)
below and subject to the mandatory  requirements  of applicable  law, to sell or
otherwise  dispose of all or any part of the  Security at public or private sale
for cash, upon credit or for future delivery as Winstar shall deem  appropriate.
Upon  consummation  of any such sale  Winstar  shall  have the right to  assign,
transfer  and deliver to the  purchaser  or  purchasers  thereof the Security so
sold.  Each  such  purchaser  at any such  sale  shall  hold the  property  sold
absolutely,  free  from any  claim or  right  on the part of  Customer  it being
understood  that  Customer  shall retain the right to redeem the Security at any
time prior to sale.

     (ii) Winstar shall give Customer 15 days'  written  notice (which  Customer
agrees is reasonable notice within the meaning of Section 9-504(3) of the UCC or
its

                                       17
<PAGE>

equivalent in other  jurisdictions)  of Winstar's  intention to make any sale of
the  Security,  pursuant to paragraph (i) above.  Such notice,  in the case of a
public sale,  shall state the time and place for such sale. Any such public sale
shall be held at such time or times within  ordinary  business hours and at such
place or places as Winstar may fix and state in the notice of such public  sale.
At any such sale, the Security,  or portion  thereof,  to be sold may be sold in
one lot as an entirety or in separate  parcels,  as Winstar may (in its sole and
absolute discretion) determine.  Winstar shall not be obligated to make any sale
of any Security if it shall determine not to do so,  regardless of the fact that
notice of sale of such  Security  shall have been given.  Winstar  may,  without
notice or  publication,  adjourn any public or private sale or cause the same to
be adjourned from time to time by  announcement  at the time and place fixed for
sale, and such sale may,  without further notice,  be made at the time and place
to which the same was so  adjourned.  In case any sale of all or any part of the
Security is made on credit or for future  delivery,  the Security so sold may be
retained by Winstar  until the sale price is paid by the purchaser or purchasers
thereof, but Winstar shall not incur any liability in case any such purchaser or
purchasers  shall fail to take up and pay for the  Security so sold and, in case
of any such failure,  such  Security may be sold again upon like notice.  At any
public (or, to the extent permitted by law,  private) sale made pursuant to this
Section,  Winstar may bid for or  purchase,  the  Security  or any part  thereof
offered  for  sale  and may  make  payment  on  account  thereof  by  using  any
"Obligation" (defined as all present and future monetary obligations of Customer
to Winstar under the Agreement) then due and payable to Winstar from Customer as
a credit  against the purchase price and Winstar may, upon  compliance  with the
terms of sale,  hold,  retain  and  dispose  of such  property  without  further
accountability  to Customer  therefor,  provided that the purchase price paid by
Winstar  reflects at least the fair market value on the secondary  market of the
Security.  For purposes hereof, a written  agreement to purchase the Security or
any portion  thereof shall be treated as a sale thereof.  As an  alternative  to
exercising the power of sale herein  conferred upon it, Winstar may proceed by a
suit or suits at law or in equity to foreclose  this  Agreement  and to sell the
Security or any portion  thereof  pursuant to a judgment or decree of a court or
courts  having  competent   jurisdiction  or  pursuant  to  a  proceeding  by  a
court-appointed receiver.

     (iii)  In the  event  Winstar  exercises  this  right  in lieu of a sale of
Security as provided  above,  then the amounts  payable to Winstar  which are in
default  shall be credited by an amount  equal to the fair market  value of such
Security  and  Winstar  shall  retain  its  rights to pursue  collection  of any
remaining unpaid amounts.

4.   Application of Proceeds. Winstar shall apply the proceeds of any collection
or sale of the Security, as well as any Security consisting of cash, as follows:

     FIRST,  to the  payment of all costs and  expenses  incurred  by Winstar in
connection  with such  collection or sale or otherwise in  connection  with this
Agreement or any of the Obligations,  including all court costs and the fees and
expenses of its agents and legal counsel,  the repayment of all advances made by
Winstar hereunder

                                       18
<PAGE>

on behalf of Customer  and any other costs or  expenses  incurred in  connection
with the exercise of any right or remedy hereunder;

     SECOND, to the payment in full of the Obligations; and

     THIRD, to Customer,  its successors or assigns,  or as a court of competent
jurisdiction may otherwise direct.

     Winstar shall have absolute discretion as to the time of application of any
such proceeds,  moneys or balances in accordance  with this  Schedule.  Upon any
sale of the Security by Winstar  (including  pursuant to a power of sale granted
by statute or under a judicial proceedings), the receipt of sale from Winstar or
of the officer making the sale shall be a sufficient  discharge to the purchaser
or purchasers of the Security so sold and such purchaser or purchasers shall not
be obligated to see to the  application  of any part of the purchase  money paid
over  to  Winstar  or  such  officer  or  be  answerable  in  any  way  for  the
misapplication thereof.

                                       19
<PAGE>

                                 SCHEDULE M-6.3

                                ALLOCATION TABLE

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------
                    Monthly Price     12 Months      10 Year    Price Per Unit    Quantity           Total
                      per Link        Per Year        Term
----------------------------------------------------------------------------------------------------------------
<S>                 <C>               <C>           <C>          <C>             <C>                 <C>
RADIO EQUIPMENT                                                          [***]      500                  [***]
----------------------------------------------------------------------------------------------------------------
INSTALLATION                                                             [***]      500                  [***]
SERVICES
----------------------------------------------------------------------------------------------------------------
O&M                          [***]       12            10                [***]      500                  [***]
----------------------------------------------------------------------------------------------------------------
BACKHAUL                     [***]       12            10                [***]      500                  [***]
----------------------------------------------------------------------------------------------------------------
IN-BUILDING                  [***]       12            10                [***]      500                  [***]
----------------------------------------------------------------------------------------------------------------
CENTRAL OFFICE               [***]       12            10                [***]       30                  [***]
COLLOCATION
----------------------------------------------------------------------------------------------------------------
                                                                                   TOTAL                 [***]
----------------------------------------------------------------------------------------------------------------
</TABLE>

[***] CONFIDENTIAL TREATMENT REQUESTED

                                       20
<PAGE>

                                    EXHIBIT A

                                       TO

                                MASTER AGREEMENT

                               EQUIPMENT PURCHASE

This Equipment  Purchase Exhibit  ("Exhibit") shall be governed by the terms and
conditions of the Master Agreement ("Master Agreement") dated as of the 30th day
of  June  2000,   between  WINSTAR   WIRELESS,   INC.   ("Winstar")  and  SAVVIS
COMMUNICATIONS CORPORATION ("Customer"). Terms used in this Exhibit that are not
defined below shall have the meaning set forth in the Master Agreement.

1.   CONVEYANCE OF THE RADIOS.

     (a) During  the Term of the  Master  Agreement,  Customer  shall  purchase,
acquire,  and accept from Winstar, all of Winstar's right, title and interest in
and to a total of five  hundred  (500) radio pairs and other  related  equipment
listed in Schedule  A-1  attached  hereto and made part of this  Exhibit (all of
which is collectively referred to hereafter as "Equipment".

     (b) Winstar shall  convey,  assign,  transfer and deliver to Customer,  and
Customer  shall  purchase Two Hundred Four (204) of such radio pairs and related
equipment on the Effective Date. Winstar shall deliver the Equipment to Customer
at the premises set forth in Schedule A-1.

2.   PAYMENT FOR EQUIPMENT.

     (a) Customer  shall pay to Winstar the amount set forth in Schedule A-1 for
the Equipment,  which shall be secured  pursuant to Schedule M-6.2 to the Master
Agreement.

     (b)  Customer  shall  make  payment  to Winstar  for the  initial  batch of
Equipment  in the manner  provided in Schedule  A-2 and detailed in the purchase
order attached hereto as Schedule A-3. For all subsequent  batches of Equipment,
Customer  shall pay  Winstar  a Thirty  percent  (30%)  down  payment,  with the
remaining amount due quarterly, on the Fifteenth (15th) day of the last month of
the quarter,  over a six (6) year period at an interest  rate of Eleven  percent
(11%) per anum.

     (c) If Customer fails to pay any amount due within fifteen (15) days of the
date due, at the option of Winstar,  the full amount remaining unpaid under this
Agreement shall become immediately due and payable without  presentment,  demand
or notice of any kind; and Winstar may exercise any or all remedies available to
it under  applicable law and the Transaction  Documents.  In addition,  Customer
shall pay to Winstar on demand a late charge equal to eighteen  percent (18%) of
the amount due.

     (d) Customer shall be responsible for all sales and/or use or similar taxes
that may be due as a result of the transfer of the Equipment.

3.  ACCEPTANCE  OF,  TITLE  TO,  AND  RISK OF LOSS OF  EQUIPMENT.  Title  to the
Equipment shall vest in Customer  immediately upon shipment of the Equipment FOB
shipping point by Winstar. Risk of loss or damage to the Equipment shall pass to
Customer  upon passage of title to the  Equipment.  Customer  acknowledges  that
Schedule 1-A hereto serves as its purchase  order for all shipments of Equipment
and that Winstar is authorized to ship against it in the amount and on the dates
specified herein.

4.  SHIPPING.  Winstar  shall:  (a) ship to the  destination  designated in this
Exhibit; (b) ship according to routing instructions given by Customer; (c) place
the order number on all subordinate documents;  (d) enclose a packing memorandum
with each  shipment  and,  when more than one package is shipped,  identify  the
package containing the memorandum; and (e) mark the order number on all packages
and shipping papers. Adequate protective packing

                                       21
<PAGE>

shall be furnished at no additional  charge.  Shipping and routing  instructions
may be furnished or altered by Customer  without a writing.  If Winstar does not
comply  with the  terms of the FOB  clause  of this  Exhibit  or with  Customer'
shipping or routing instructions, Winstar authorizes Customer to deduct from any
invoice of Winstar (or to charge back to Winstar),  any increased costs incurred
by Customer as a result of Winstar's noncompliance.  Winstar will be responsible
for paying all shipping costs to Customer' premises indicated in the attached.

5. UPGRADE OF  EQUIPMENT.  Upon mutual  agreement of the Parties,  Customer may,
upon providing thirty (30) days written notice to Winstar,  sell back to Winstar
any  Equipment at the fair market value of the  Equipment,  as  determined  by a
commercially  reasonable method of valuation agreed to by the Parties, as of the
effective  date of the  repurchase.  Customer  may only  exercise  its option to
upgrade once during the Term of the Master Agreement. In consideration, and upon
exercise  of such  option,  Customer  shall  purchase,  upon  similar  terms and
conditions as those described  herein,  Equipment with greater capacity than the
Equipment sold back to Winstar.  Winstar shall inform Customer of the repurchase
price of the Equipment as well as the purchase  price of the upgraded  Equipment
as soon as  practicable  after  receipt of notice from Customer of its intent to
exercise  its option to upgrade the  Equipment  pursuant to this  Section.  This
upgrade  clause shall be available  during the year following the Effective Date
only.

                      (THIS SPACE INTENTIONALLY LEFT BLANK)

IN WITNESS  WHEREOF,  the Parties hereto have caused this Exhibit to be executed
by their duly authorized representatives.

SAVVIS COMMUNICATIONS                    WINSTAR WIRELESS, INC.
CORPORATION

By:                                      By:
      ----------------------------              --------------------------------

Name:                                    Name:
      ----------------------------              --------------------------------

Title:                                   Title:
      ----------------------------              --------------------------------

Date:                                     Date:
      ----------------------------              --------------------------------

                                       22
<PAGE>

                                  SCHEDULE A-1

                                       TO

                           EQUIPMENT PURCHASE EXHIBIT

                                 ALLOCATION LIST

Number of Radio Pairs                                    500

PRICE PER RADIO PAIR                                 [***](OC-3)

                                                     [***](DS-3)

Customer Premises for Delivery:

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

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

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

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

ATTENTION:
          ----------

[***] CONFIDENTIAL TREATMENT REQUESTED

                                       23
<PAGE>

                                  SCHEDULE A-2

                                       TO

                           EQUIPMENT PURCHASE EXHIBIT

<TABLE>
<CAPTION>
        -------------------------------------------------
        -------------------------------------------------
             DATE                      PAYMENT
             ----                      -------
         <S>                          <C>
        -------------------------------------------------
                     6/30/00              [***]
        -------------------------------------------------
                     9/15/00              [***]
        -------------------------------------------------
                    12/15/00              [***]
        -------------------------------------------------
                     3/15/01              [***]
        -------------------------------------------------
                     6/15/01              [***]
        -------------------------------------------------
                     9/15/01              [***]
        -------------------------------------------------
                    12/15/01              [***]
        -------------------------------------------------
                     3/15/02              [***]
        -------------------------------------------------
                     6/15/02              [***]
        -------------------------------------------------
                     9/15/02              [***]
        -------------------------------------------------
                    12/15/02              [***]
        -------------------------------------------------
                     3/15/03              [***]
        -------------------------------------------------
                     6/15/03              [***]
        -------------------------------------------------
                     9/15/03              [***]
        -------------------------------------------------
                    12/15/03              [***]
        -------------------------------------------------
                     3/15/04              [***]
        -------------------------------------------------
                     6/15/04              [***]
        -------------------------------------------------
                     9/15/04              [***]
        -------------------------------------------------
                    12/15/04              [***]
        -------------------------------------------------
                     3/15/05              [***]
        -------------------------------------------------
                     6/15/05              [***]
        -------------------------------------------------
                     9/15/05              [***]
        -------------------------------------------------
                    12/15/05              [***]
        -------------------------------------------------
                     3/15/06              [***]
        -------------------------------------------------
                     6/15/06              [***]
        -------------------------------------------------
</TABLE>

[***] CONFIDENTIAL TREATMENT REQUESTED

                                       24
<PAGE>

                                  SCHEDULE A-3

                                       TO

                           EQUIPMENT PURCHASE EXHIBIT

                                 PURCHASE ORDER

SAVVIS

PURCHASE  ORDER
---------------
<TABLE>
<S>                                                          <C>
                                                              --------------------------------------------------
                                                              SHIP  TO : SAVVIS/MERIDIAN

---------------------------------------------------------
PAYMENT  TERMS :  PER  CONTRACT                               5160 SANDY LEWIS DRIVE
DELIVERY TERMS: FOB SHIPPING POINT                            FAIRFAX, VA 22033

                                                              ATTN: JOHN GRIMSLY (703) 503 2900
---------------------------------------------------------     --------------------------------------------------

<CAPTION>
DESCRIPTION                                                   QTY           PRICE               EXTENDED  PRICE
-----------                                                   ---           -----               ---------------
<S>                                                          <C>           <C>                 <C>
75 OC3 RADIOS PAIRS:

Basic OC-3 IDU with  SNMP, 64K user channel, 10BT Wayside      75          [***]                          [***]
Channel and 1300nm F/O MM main channel
Basic OC-3 IDU with SNMP, 64K user channel, 10BT Wayside       75 [***]           [***]
channel and 1300nm F/O SM main channel
ODU 38Ghz, Band 3A                                             75 [***]           [***]
 ODU 38Ghz, Band 3B                                            75 [***]           [***]
1 Ft Antenna                                                  150 [***]           [***]
EtherAir - 2 port 100 base-T interface                        150 [***]           [***]
100BT to 100BFX converter                                     150 [***]           [***]
                                                                                  ------------------------------
                                                 SUBTOTAL                                                 [***]
                                 (PRICE PER  RADIO  PAIR)                                                 [***]

272  DS3  RADIO  PAIRS:

38 GHZ DS3 XP4 ODU BAND 1 LOW                                 136 [***]           [***]
38 GHZ DS3 XP4 ODU BAND 1 HIGH                                136 [***]           [***]
38 GHZ DS3 XP4 ODU BAND 2 LOW                                 136 [***]           [***]
38 GHZ DS3 XP4 ODU BAND 2 HIGH                                136 [***]           [***]
DS3 XP4 IDU WITH SNMP AND ATPC OPTION                         544 [***]           [***]
1 FT 38DBI ANTENNA                                            544 [***]           [***]
                                                                                  ------------------------------
                                                 SUBTOTAL                                                 [***]
                                 (PRICE PER  RADIO  PAIR)                                                 [***]

TOTAL                                                                                                     [***]
</TABLE>

Upon mutual consent by both parties, Savvis may upon 30 days notice sell back to
Winstar DS3 radio links at fair market value in exchange for Savvis  purchase of
OC3 radio links under the same terms and  conditions  outlined in the  equipment
sale agreement. This upgrade clause is valid until June 30, 2001.

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

Authorized Signature                                     Date
--------------------------------------------------------------------------------
[***] CONFIDENTIAL TREATMENT REQUESTED

                                       25
<PAGE>

BILL OF SALE

THIS BILL OF SALE by and between  Winstar  Wireless,  Inc.  and Customer is made
pursuant to that certain Equipment  Purchase  Agreement (the "Exhibit")  between
the Parties of even date  herewith.  All  capitalized  terms used herein and not
otherwise defined shall have the meanings given to them in the Exhibit.

FOR AND IN CONSIDERATION of the mutual promises contained, and the consideration
recited,  in the  Exhibit,  and for other good and valuable  consideration,  the
receipt and adequacy of which are hereby acknowledged,  and subject to the terms
and conditions of the Exhibit, Winstar hereby bargains,  sells, grants, conveys,
transfers  and assigns to  Customer,  its  successors  and  assigns,  all of the
Equipment listed on Schedule A, attached hereto and to the Exhibit.

IN WITNESS WHEREOF,  Winstar has caused this Bill of Sale to be duly executed on
the day and year written in the Exhibit.

ATTEST/WITNESS:                 WINSTAR WIRELESS, INC.

--------------------                -----------------------------
                                    BY:
                                       --------------------------

                                       26
<PAGE>

                                    EXHIBIT B

                                       TO

                                MASTER AGREEMENT

                              INSTALLATION SERVICES

This  Installation  Services Exhibit  ("Exhibit") shall be governed by the terms
and conditions of the Master Agreement ("Master Agreement") dated as of the 30th
day of  June,  2000  between  WINSTAR  WIRELESS,  INC.  ("Winstar")  and  SAVVIS
COMMUNICATIONS CORPORATION ("Customer"). Terms used in this Exhibit that are not
defined below shall have the meaning set forth in the Master Agreement.

1.  BUILDINGS.  Customer  shall,  no later than sixty  (60) days  following  the
Effective  Date,  provide to  Winstar a list of seven  hundred  and fifty  (750)
buildings in which it desires to have  Equipment  installed  ("Customer  List").
SAVVIS  shall  order the  Customer  List  from the  building  with the  greatest
priority to have Equipment  installed to the building with the least priority to
have  Equipment  installed.  This list shall not contain any buildings that were
previously  proposed  to Winstar by  Customer  to become an  Eligible  Location.
Savvis may add to the Customer List once per calendar quarter.

2.  INSTALLATION  PROCESS.  Once Winstar has installed One Hundred and Two (102)
radio pairs under this Agreement ("Inventory Event"), Customer shall be required
to maintain  an  Inventory  of One  Hundred and Two (102) radio pairs  ("Minimum
Inventory").  To do so,  within  fifteen  (15) days after the  Inventory  Event,
Winstar  shall  notify  Customer of the  buildings at which  Winstar  reasonably
believes it can install radio pairs within  Seventy-Five (75) days of the notice
("Initial Radio Pair Notice").  In determining the buildings to be placed on the
Initial  Radio Pair Notice,  Winstar shall attempt to install radio pairs in the
priority order  buildings  appear on the Customer  List.  Every Thirty (30) days
thereafter,  Winstar  shall  notify  Customer  of the  next  One  Hundred  (100)
buildings at which it believes it can install  radio pairs  within  Seventy-Five
(75)  days  of the  additional  notice  ("Additional  Radio  Pair  Notice").  In
determining  the  buildings  to be placed on the  Additional  Radio Pair Notice,
Winstar  shall attempt to install  radio pairs in the priority  order  buildings
appear on the Customer List.  Customer will every Thirty (30) days purchase from
Winstar any  additional  radio pairs  necessary for Customer to have on hand the
Minimum  Inventory.  Customer will thereafter select from the Initial Radio Pair
Notice and any Additional  Radio Repair  Notice,  the buildings it desires to be
installed by Winstar, ensuring that at all times, Customer has selected at least
One Hundred and Two (102)  buildings.  This process shall terminate when Winstar
has  installed a total of Five  Hundred  (500) radio pairs at  buildings  on the
Customer List. Notwithstanding the foregoing, Winstar may without penalty choose
not to  install  more  pairs at no more  then 2% of  Locations  set forth on the
Initial and any Additional Radio Pair Notice.

3.  INSTALLATION  SERVICES.  Winstar shall be responsible for the payment of all
fees and expenses associated with roof acquisition or rental costs.

4.  ADDITIONAL INSTALLATION SERVICES.

     (a) At the request of Customer,  Winstar shall move any Installed Equipment
from its place of  installation  to any Eligible  Location or to its  designated
inventory storage facilities. Winstar will treat all such moves as a "move, add,
change, or delete" ("MACD").

     (b)  Customer  shall pay  Winstar for all costs  associated  with such MACD
(i.e., decommissioning,  deinstallation, and reinstallation) at Winstar's actual
cost, without mark-up.

5.  LINK TESTING.

<PAGE>

     (a) The Parties  shall develop a mutually  agreed-upon  test plan for Links
within thirty (30) days of the Effective Date.

     (b) After the Equipment  for a Link is  installed,  Winstar shall deliver a
Link Availability Letter to Customer.  Customer shall initiate and complete Link
testing  within three (3) Business Days of the receipt of the Link  Availability
Letter. Customer shall countersign the Link Availability Letter within three (3)
Business  Days of Customer's  receipt of the Link  Availability  Letter.  In the
event that a counter-signed  Link  Availability  Letter, or written objection by
Customer,  to the Link Availability  Letter  designating items on which the Link
has failed a Link test and a detailed  explanation  of such testing and results,
is not received by Winstar within three (3) business days of Customer's  receipt
of the Link  Availability  Letter,  the subject  Link  provided  shall be deemed
installed.

     (c) Each Link shall be tested to ensure that the tested Equipment  performs
to its applicable specifications.

6. PAYMENT FOR INSTALLATION SERVICES.

     (a) In consideration of the installation  services pursuant to this Exhibit
("Installation  Services") Customer shall pay to Winstar the amount set forth in
Schedule  B-6.  Customer  shall pay to Winstar of the cost of such  Installation
Services no later than thirty (30) days after  receipt of the Link  Availability
Letter.

     (b) Customer shall be responsible for all sales and/or use or similar taxes
that may be due as a result of the Installation Services.

7. COVENANTS,  REPRESENTATIONS  AND WARRANTIES.  Each Party covenants and agrees
that  it  has  or  shall   obtain  any  and  all  rights,   licenses,   permits,
authorizations,  consents and  approvals  (including,  without  limitation,  any
necessary  local,  state,  federal or tribal  authorizations  and  environmental
permits) as are  reasonably  necessary in order to permit them to perform  their
obligations hereunder.

IN WITNESS  WHEREOF,  the Parties hereto have caused this Exhibit to be executed
by their duly authorized representatives.

SAVVIS COMMUNICATIONS                   WINSTAR WIRELESS, INC.
CORPORATION

By:                                     By:
      -------------------------------           ------------------------------

Name:                                   Name:
      -------------------------------           ------------------------------

Title:                                  Title:
      -------------------------------           ------------------------------

Date:                                   Date:
      -------------------------------           ------------------------------

                                       28
<PAGE>

                                  SCHEDULE B-6

                                PRICING SCHEDULE

[***] per Link

All installation charges include standard  installation up to common space area.
Out of scope  work  shall be  billed  at cost  plus ten  percent  (10%),  unless
otherwise stated in this Exhibit.

[***] CONFIDENTIAL TREATMENT REQUESTED

                                       29
<PAGE>

                                    EXHIBIT C

                                       TO

                                MASTER AGREEMENT

                             LOCAL CONNECTIVITY AND
                           BACKHAUL TRANSPORT SERVICES

This Exhibit  ("Exhibit")  shall be governed by the terms and  conditions of the
Master Agreement  ("Master  Agreement")  dated as of the 30th day of June, 2000,
between WINSTAR WIRELESS, INC. ("Winstar") and SAVVIS COMMUNICATIONS CORPORATION
("Customer").  Terms used in this Exhibit that are not defined  below shall have
the meaning set forth in the Master Agreement.

1. PROVISION  OF  LOCAL  CONNECTIVITY.  Winstar  shall  provide to Customer  and
Customer agrees to purchase from Winstar Local Connectivity in the form of Links
between Winstar hub locations and Eligible Locations.  Customer shall not resell
to other  entities all or any portion of any Local  Connectivity  purchased from
Winstar pursuant to this Exhibit.

2. BACKHAUL TRANSPORT SERVICES. As an adjunct to the Local Connectivity, Winstar
shall provide to Customer transport facilities from Winstar hub locations,  used
to provide Local Connectivity, to Customer collocation cages at Winstar's switch
sites, all as more particularly listed in Schedule C-2.

IN WITNESS  WHEREOF,  the Parties hereto have caused this Exhibit to be executed
by their duly authorized representatives.

SAVVIS COMMUNICATIONS                      WINSTAR WIRELESS, INC.
CORPORATION

By:                                        By:
     ----------------------------------          -------------------------------

Name:                                      Name:
     ----------------------------------          -------------------------------

Title:                                    Title:
      ---------------------------------          -------------------------------

Date:                                      Date:
     ----------------------------------          -------------------------------

                                       30
<PAGE>

                                  Schedule C-2
                             Winstar's Switch Sites

                                       31
<PAGE>

                                    EXHIBIT D

                               TO MASTER AGREEMENT

                      EQUIPMENT OPERATIONS AND MAINTENANCE

This Equipment  Operations and Maintenance Exhibit ("Exhibit") shall be governed
by the terms and conditions of the Master Agreement  ("Master  Agreement") dated
as of the 30TH day of June, 2000, between WINSTAR WIRELESS, INC. ("Winstar") and
SAVVIS COMMUNICATIONS CORPORATION ("Customer").  Terms used in this Exhibit that
are not defined below shall have the meaning set forth in the Master Agreement.

1. PROVISION OF EQUIPMENT SUPPORT SERVICES

     1.1 Winstar shall provide to Customer, and Customer agrees to purchase from
Winstar, all testing,  maintenance,  monitoring,  sparing,  spectrum management,
restoration  and repair  services for the upkeep of the  Equipment and the Local
Connectivity (the "Equipment Support Services"). Such Equipment Support Services
may include,  but are not  necessarily  limited to:  performing  maintenance and
upkeep on the  installed  Equipment,  repairing  and  calibrating  the installed
Equipment,  and performing  frequency  coordination and  interference  analyses.
Winstar  will  maintain  the  Equipment  and all  other  equipment  or  software
(including,  without  limitation,  cabling) provided by Winstar.  Winstar,  or a
Winstar designee,  will provide the Equipment Support Services  according to its
standard operating procedures.

     1.2 Winstar  shall pass through to Customer all  manufacturers'  warranties
from the  manufacturers  of the Equipment to the extent Winstar is able pursuant
to any  agreements  between  Winstar and such  manufacturers.  In the event that
Winstar is unable to do so, Winstar shall enforce such manufacturers' warranties
on Customer's behalf.  Winstar shall perform the Equipment Support Services in a
good and  workmanlike  manner,  in  accordance  with its standard  operating and
maintenance  procedures.  Winstar shall use commercially  reasonable  efforts to
cause the Equipment to remain in good working order and condition.  Winstar will
maintain  remote  monitoring  of the  Equipment  for  surveillance  purposes  in
accordance with its standard procedures.

     1.3  Customer  shall  be  responsible  for the use and  compatibility  with
Winstar's Network of any of Customer's  equipment,  including but not limited to
the Equipment.

     1.4 Any scheduled  maintenance  (non-emergency)  shall be performed at such
times so as to minimize any  disruption  of Customer's  service and  operations.
Winstar shall cooperate with Customer in scheduling any such maintenance.  Where
practicable,  any scheduled  maintenance  that is expected to produce any signal
discontinuity shall be scheduled after midnight and before 6:00 a.m. local time.
Winstar shall to the extent practical notify Customer in advance of the date and
time of any scheduled  maintenance  and as soon as  practicable  after  becoming
aware of the need for any non-routine maintenance.

                                       32
<PAGE>

2. ASSIGNMENT OF EQUIPMENT SUPPORT SERVICES

     Winstar may assign or  subcontract  to or otherwise  have,  any third party
perform any or all of the Equipment  Support  Services under this Exhibit at any
time,  without the consent of Customer,  provided that Winstar shall continue to
remain responsible for any such duties.

3. OUTAGES/OUTAGE CREDITS

     3.1 In the  event  of an  interruption  of  service  for one or more of the
Equipment hereunder, resulting from physical damage to, or other failure of, any
Equipment,  or otherwise ("Outage"),  Customer shall notify Winstar by telephone
at (888)  569-2525 or through such other  notification  procedure as Winstar may
establish.  Provided  that  Winstar  personnel  or  contractors  have  access to
affected  Customer  facilities  immediately  upon  notification,  if  necessary,
Winstar shall respond and commence work within three (3) hours from notification
by Customer and use commercially  reasonable efforts to restore effective use of
the Equipment as expeditiously as practicable,  with a goal of no more than five
(5) hours from receipt by Winstar of  Customer's  notification  or from the time
Winstar otherwise becomes aware of such interruption.

     3.2  Each  OC-3  Link  will  have  a   performance   standard  of  99.99  %
availability. An "OC-3" Link, for purposes of this Agreement shall be defined as
the Link from the SAVVIS collocation rack in the Winstar POP to the OC-3 port on
the  Customer-provided  Lucent  Stinger  (including  the fiber  patch cable that
connects  from the  radio IDU to the  Stinger).  Performance  shall be  measured
quarterly on an OC-3  Link-by-OC-3  Link basis. For each OC-3 Link that does not
meet the  performance  standard  above,  Winstar will give  Customer a credit of
[***] towards future Equipment Support  Services.  THE FOREGOING STATES THE SOLE
AND  EXCLUSIVE  REMEDY OF  Customer,  AND  LIABILITY  OF WINSTAR,  FOR ANY TOTAL
OUTAGES.

     3.3  If  all or  part  of the  Equipment  or  Local  Connectivity  requires
restoration, replacement or repair during the Term solely as a result of an act,
or any failure to act on the part of Customer as required  hereunder,  including
without  limitation,  the  negligence  or willful  misconduct  of Customer,  its
officers,   employees,   agents,   contractors,   subcontractors,   invitees  or
representatives,  such repair,  replacement  and/or  restoration will be made by
Winstar,  at Customer's sole expense,  in accordance with Winstar's then current
time and materials rates plus applicable  taxes. In addition,  Customer will not
receive any Outage Credit resulting from the foregoing. If any such restoration,
replacement  or repair is  required as a result of the act, or failure to act as
required hereunder,  by Customer and Winstar,  the costs shall be apportioned in
accordance with their respective responsibility therefor.

4. RATES, BILLING AND PAYMENT FOR SERVICES.

A. AS CONSIDERATION  FOR WINSTAR'S  PROVISION OF THE EQUIPMENT SUPPORT SERVICES,
CUSTOMER SHALL PAY WINSTAR THE OPERATIONS AND MAINTENANCE FEES SET

[***] CONFIDENTIAL TREATMENT REQUESTED

                                       33
<PAGE>

FORTH IN SCHEDULE D-4 (THE  "EQUIPMENT  SUPPORT  CHARGES")  COMMENCING  UPON THE
RADIO INSTALL  DATE.
B. Winstar shall invoice Customer on a monthly basis in advance.  Invoices shall
be payable upon receipt.  If payment is not received  within thirty (30) days of
the payment due date, the invoice will accrue interest at the lesser of 1.5% per
month or the highest  rate  permitted  by law. In the event that  payment is not
received within sixty (60) days of the payment due date, Winstar may suspend the
Equipment Support Services,  in Winstar's sole discretion.  If Equipment Support
Services  are  suspended,   Equipment  Support  Services  will  be  restored  or
recommenced when all Equipment Support Charges and interest are paid in full.

5. Relocation.

     5.1 If Winstar determines for bona fide operational reasons, or is required
by a third party within its proper  authority or by a  governmental  entity,  to
relocate  all or any  Equipment  (as  defined in Exhibit  A), (a  "Relocation"),
Winstar  shall,  to the extent  practicable,  provide  Customer sixty (60) days'
prior notice of any such  Relocation  and shall  proceed  with such  Relocation.
Winstar shall also keep Customer informed of any governmental  proceedings which
would  require  such  Relocation.  Winstar  shall have the right to direct  such
Relocation,  including  the right to determine the extent of, the timing of, and
methods to be used for such Relocation,  and shall keep Customer informed of the
same.

     5.2. For  purposes of this  Section,  a  Relocation  shall be for bona fide
operational  reasons if it is  undertaken in good faith (i) to settle or avoid a
bona fide  threatened or filed  condemnation  action or order by a  governmental
authority to relocate,  (ii) to reduce the likelihood of physical  damage to the
Winstar Network, (iii) as the result of a force majeure event, or (iv) for other
operational  reasons to which  Customer has  consented,  provided  that Customer
shall not  unreasonably  withhold  such consent.  Winstar  shall use  reasonable
efforts to contest any exercise of  condemnation  authority that would require a
Relocation.

     5.3.  Winstar  will  Relocate  the  Equipment  and all other  equipment  or
software provided by Winstar.  Winstar will also be responsible for reinstalling
such  Equipment at its new Eligible  Location in accordance  the  procedures set
forth in Exhibit B. Customer shall be responsible for the use and  compatibility
with Winstar's Network of any Equipment.

     6. Term.
     The term of this Exhibit shall  commence as of the Effective Date and shall
remain in force for an initial term of ten (10) years.

7. BUILDING SLA

                                       34
<PAGE>

     7.1 Winstar  shall  install a total of One Hundred and Two (102) Links,  in
accordance  with the terms and  conditions set forth in Exhibit B, no later than
one (1) year after the Effective Date  ("Installation  Target").  In determining
whether Winstar has met the  Installation  Target,  Winstar shall be entitled to
count as an installed  Link all  buildings to which  Winstar is providing  local
connectivity (for example,  Winstar hub building).  In the event that Winstar is
unable to meet the  Installation  Target,  the remedy  set forth in Section  7.2
shall be Customer's sole and exclusive remedy.

     7.2 Beginning on the first  anniversary  of the Effective  Date,  and every
month  thereafter,  Winstar  shall credit  Customer an amount equal to [***] per
month toward the purchase of future Equipment Support Services,  as set forth in
this Exhibit,  for each Link below the Installation  Target. For example,  if by
July 30th,  2001,  Winstar has installed  eighty-two  (82) Links,  Winstar shall
credit  Customer  with [***]  toward the  purchase of future  Equipment  Support
Services [(20 Links under the Installation Target)[***]. If Winstar is only able
to install an additional five (5) Links by August 30, 2001, Winstar shall credit
Customer  with an  additional  [***]  toward the  purchase  of future  Equipment
Support Services [(15 Links under the Installation Target)[***].

IN WITNESS  WHEREOF,  the Parties hereto have caused this Exhibit to be executed
by their duly authorized representatives.

SAVVIS COMMUNICATIONS                    WINSTAR WIRELESS, INC.
CORPORATION

By:                                      By:
       --------------------------------        ---------------------------------

Name:                                    Name:
       --------------------------------        ---------------------------------

Title:                                   Title:
       --------------------------------
                                               ---------------------------------

Date:                                     Date:
       --------------------------------        ---------------------------------

[***] CONFIDENTIAL TREATMENT REQUESTED

                                       35
<PAGE>

                                  SCHEDULE D-4

                       OPERATIONS AND MAINTENANCE CHARGES

[***] per month per Link

[***] CONFIDENTIAL TREATMENT REQUESTED

                                       36
<PAGE>

                                    EXHIBIT E

                                       TO

                                MASTER AGREEMENT

                            WINSTAR COLLOCATION SPACE

THIS WINSTAR  COLLOCATION EXHIBIT ("EXHIBIT") SHALL BE GOVERNED BY THE TERMS AND
CONDITIONS OF THE MASTER AGREEMENT ("MASTER AGREEMENT") DATED AS OF THE 30TH DAY
OF  JUNE  2000,   BETWEEN  WINSTAR   WIRELESS,   INC.   ("WINSTAR")  AND  SAVVIS
COMMUNICATIONS CORPORATION ("CUSTOMER"). TERMS USED IN THIS EXHIBIT THAT ARE NOT
DEFINED BELOW SHALL HAVE THE MEANING SET FORTH IN THE MASTER AGREEMENT.

1. License to Occupy, Permissible Use and Relocation Provisions.

     (a) Winstar, or its Affiliates (Winstar and its Affiliates are collectively
referred to as "Winstar Affiliates"),  owns, controls or has leasehold interests
in certain office and storage space within commercial  buildings  throughout the
United States (each specific  building as a whole to be defined as a "Premises")
which  are  suitable  for the  placement  and  operation  of  telecommunications
equipment. Pursuant to the Master Agreement and this Exhibit, Winstar Affiliates
shall provide  Customer access to the Premises in one or more locations  therein
for the purpose of placing  certain  telecommunications  equipment  and cabling,
including  all of its  nodes  (the  "Customer  Equipment"),  at each  individual
location within the Premises (each a "Terminal Facility").

     (b) This Exhibit shall  comprise a complete and binding  agreement  between
Customer  and a Winstar  Affiliate  only upon  prior  execution  by the  Winstar
Affiliate and Customer of a Collocation Schedule, in the form attached hereto as
Schedule  E-1,  pertaining  to an  individual  Terminal  Facility,  in which the
Winstar Affiliate has a leasehold interest.  Each Collocation Schedule,  and any
amendments thereto,  when dated and subscribed to by Customer and the applicable
Winstar Affiliate, shall incorporate the terms and conditions of this Exhibit as
well as the Master Agreement, and be made part of both by reference.  References
in this Exhibit to rights or  obligations  of Winstar  shall refer to the rights
and obligations of the Winstar  Affiliate  named in the appropriate  Collocation
Schedule with respect to the Terminal Facility to which it pertains.

     (c) Each  Collocation  Schedule  shall have attached  thereto the following
Attachments:  Facility  Drawings,  identified  as  "Attachment  1"; and  General
Description  of Work  Tasks and  Special  Terms and  Conditions,  identified  as
"Attachment 2".

                                       37
<PAGE>

     (d) Customer  shall utilize the specific area  designated by Winstar within
the Terminal  Facility (the "Space")  only for  interconnection  of the Customer
Equipment to the network services of Winstar.

     (e) Pursuant to the terms and  conditions  of this  Exhibit,  Winstar shall
provide to Customer up to two (2)] racks of collocation  space, where available,
within  the  Terminal  Facility  at  Winstar-designated  central  office and hub
Terminal Facilities as specified in the Collocation Schedules.

     (f) Customer  shall be responsible  for delivering any additional  Customer
network  elements  to a point  of  demarcation  in the  Space as  designated  by
Winstar.  Winstar shall be responsible for  transporting  such network  elements
from the point of demarcation to the collocated Customer Equipment.

     (g) In connection  with the Space made available  hereunder,  Winstar shall
perform  services which support the overall  operation of the Terminal  Facility
(e.g., janitorial services,  environmental systems maintenance,  and power plant
maintenance)  at no additional  charge to Customer.  However,  Customer shall be
required to maintain the Space in an orderly manner and shall be responsible for
the  removal  of trash,  packing,  cartons,  and  related  items from the Space.
Further,  Customer shall maintain the Space in a safe condition  including,  but
not limited to, the  preclusion of storing  combustible  materials in the Space.
Winstar,  however, will have no operations or maintenance  responsibilities with
respect to Customer's Equipment,  except as such responsibilities pertain to the
construction work, if specifically contemplated by this Agreement.

     (h) Unless otherwise  provided in the Collocation  Schedule,  each visit by
Customer to the Space will be deemed to utilize  escort  services  furnished  by
Winstar  from the time  Customer's  employee(s)  sign(s)  in upon  entering  the
Terminal  Facility to the time Customer's  employee(s)  sign(s) out upon leaving
the Terminal Facility.

     (i)  Customer  acknowledges  and  agrees  that it has been  granted  only a
limited,  non-exclusive  license  to occupy the Space for the period of time and
under the terms  and  conditions  set  forth in the  Transaction  Documents  and
herein, and that it has not been granted any real property interests of any kind
in the Space, Premises, or the Terminal Facility.

     (j) The  Equipment  shall remain  Customer's  exclusive  personal  property
throughout the Term, and upon  termination of this Exhibit,  Customer shall have
the right to remove all  Equipment at  Customer's  sole expense on or before the
expiration or earlier termination of this Exhibit; provided Customer repairs any
damage to the Space, Premises or Terminal Facility caused by such removal.

     (k) Customer shall keep the Space,  Premises,  Terminal  Facilities and the
Equipment  free  from any  liens  arising  from any  work  performed,  materials
furnished or obligations incurred by or at the request of Customer.  All persons
either contracting

                                       38
<PAGE>

with Customer or furnishing or rendering  labor and materials to Customer  shall
be  notified in writing by  Customer  that they must look only to  Customer  for
payment  for any labor or  materials.  If any lien is filed  against  the Space,
Premises,  Terminal  Facility,  or the  Equipment  as a  result  of the  acts or
omissions of Customer,  its employees,  agents or contractors or subcontractors,
Customer  shall  discharge  it or bond it off  within  thirty  (30)  days  after
Customer learns that the lien has been filed.

     (l) The Parties acknowledge and agree that Schedule E-2 attached hereto and
integrated  herein sets out their  entire  obligations  with regards to the OC-3
Link referenced therein.

2. DSLAM Collocation.

     (a) In addition to the collocation  services provided above,  Winstar shall
make  all  reasonable   efforts  to  provide  Digital   Subscriber  Line  Access
Multiplexer ("DSLAM") service to Customer.

     (b) In providing  DSLAM  collocation to Customer,  Winstar may, at its sole
reasonable  discretion,  provide:  (i) rack space at an Eligible  Location for a
multiplexer  or (ii) a port  within  Winstar's  own  multiplexer  located at the
Eligible Location.

     (c) In deciding whether to offer DSLAM collocation to Customer, Winstar may
consider its own business objectives with respect to space on a rack or ports in
a multiplexer.

3. Term, Termination and Renewal.

     (a)  Customer's  license to occupy each Space shall begin on the "Requested
Service  Date," as set forth in  paragraph 3 of each fully  executed  individual
Collocation Schedule or on the date Winstar completes  preparation of the Space,
whichever  is later,  and shall  continue  for the lesser of the duration of the
Term or Winstar's  underlying  leasehold  interest.  In the event that Winstar's
underlying  leasehold  interest  in a  Terminal  Facility  expires  prior to the
expiration of the Term,  Winstar  shall,  at least one hundred twenty (120) days
before the  expiration of such leasehold  interest,  make a good faith effort to
renew the underlying  leasehold interest to allow Customer to continue to occupy
the Space for the duration of the Term.

     (b) Upon termination or expiration of the license for each Space,  Customer
agrees  to remove  the  Customer  Equipment  and  other  property  that has been
installed by Customer or Customer's agents (or by Winstar on behalf of Customer,
if Winstar  desires such  Customer  Equipment to be removed).  In the event such
Customer  Equipment  or property has not been  removed  within  thirty (30) days
after the effective  termination or expiration date, then the Customer Equipment
shall be deemed abandoned and Customer shall lose all rights and title thereto.

                                       39
<PAGE>

     (c) In the event the Terminal  Facility  becomes the subject of a taking by
eminent domain by any authority having such power,  Winstar shall have the right
to terminate  the affected  Collocation  Schedule.  Winstar  shall give Customer
prompt advance notice, to the extent  practicable of important  developments and
the  removal  Schedule  as it learns of the same.  Customer  shall have no claim
against Winstar for any relocation  expenses,  any part of any award that may be
made for such taking or the value of any unexpired term or renewed  periods that
result  from a  termination  by  Winstar  under this  provision,  or any loss of
business  from  full  or  partial   interruption  or  interference  due  to  any
termination.  However, nothing contained in this Exhibit shall prohibit Customer
from seeking any relief or remedy against the condemning  authority in the event
of an eminent domain proceeding or condemnation that affects the Space.

4. Prices and Payment Terms.

     (a) Customer  shall pay to Winstar  consideration  in  accordance  with the
pricing set forth in  Collocation  Schedule E-3 pursuant to terms and conditions
set forth in the Master Agreement.

     (b) At any time during the Term, if Customer  requests that Winstar provide
services not set forth in this Exhibit,  Collocation Schedule(s) or any Schedule
attached  hereto,  Customer  agrees to pay Winstar's then current price for such
services at the time such services are rendered.

     (c)  Customer  agrees  to  reimburse  Winstar  promptly  for all  repair or
restoration  costs  associated  with damage or destruction  caused by Customer's
personnel,  Customer's agents,  Customer's  suppliers/contractors  or Customer's
visitors  during  the Term or as a  consequence  of  Customer's  removal  of the
Customer Equipment or property installed in the Space.

5.   Additional  Terms  Governing  Use of  Collocation  Space;  Installation  of
     Customer Equipment.

     (a) Before  beginning any delivery,  installation,  replacement  or removal
work, Customer must obtain Winstar's written approval with respect to Customer's
choice of suppliers and  contractors,  which approval shall not be  unreasonably
withheld.  Winstar may request  additional  information before granting approval
and may require reasonable  scheduling changes and substitution of suppliers and
contractors  as  conditions  of its  approval.  Approval  by  Winstar  is not an
endorsement  of  Customer's  supplier or  contractor,  and Customer  will remain
solely  responsible  for the  selection  of the supplier or  contractor  and all
payments   for   construction   work  or  any  other  work   relating   thereto.
Notwithstanding  any provision herein to the contrary,  Winstar may, at its sole
discretion,  perform  some or all of the work  required in  connection  with the
installation of Customer equipment, and Customer shall bear all reasonable costs
in connection therewith.  In the event Winstar performs any of the work required
in connection with the  installation of Customer  equipment,  Winstar shall send
advance

                                       40
<PAGE>

notice to Customer's Chief  Technology  Officer via electronic mail or any other
comparable communication device.

     (b)  Customer  shall  not  make  any   construction   changes  or  material
alterations  to the interior or exterior  portions of the Space,  including  any
cabling  or  power  supplies  for  the  Customer  Equipment,  without  obtaining
Winstar's  prior  written  approval for  Customer to have the work  performed or
having  Winstar  perform the work.  Winstar  shall have the right to perform and
manage any construction or material alterations within the Terminal Facility and
Space areas at rates to be negotiated between the Parties hereto.

     (c)  Customer's  access  to  the  Terminal  Facility,  use  of  the  Space,
installation  of  the  Customer  Equipment,   and  type  of  Customer  Equipment
installed,  shall at all times be subject to  Customer's  adherence to generally
accepted industry  standards,  rules and requirements of the Premises,  security
rules, and reasonable  requirements and rules of conduct  established by Winstar
for the Terminal  Facility and Space.  Without limiting the foregoing,  Customer
acknowledges  and agrees that it shall not be  permitted to install or otherwise
utilize  Customer   Equipment  that  (i)  provides   switching  or  transmission
capabilities;  (ii) creates  heat greater than 1200 watts per cabinet;  or (iii)
has a weight load of greater than 100 pounds per square foot. Customer shall not
erect  any  signs or  devices  to the  exterior  portion  of the  Space  without
submitting the request to Winstar and obtaining Winstar's written approval which
may be withheld in its sole discretion.

     (d) Customer may not provide,  or make available to any third party,  space
within the Collocation Space without Winstar's prior written consent,  which may
be  withheld  in its  sole  discretion.  If  Customer  should  provide,  or make
available  to any third  party,  space within the Space  without  obtaining  the
written  consent of  Winstar,  Customer  shall be in breach of this  Exhibit and
Winstar may pursue any legal or equitable  remedy,  including but not limited to
the immediate termination of the license pursuant to Section 6 below.

     (e)  Notwithstanding  any  other  provisions  of  this  Exhibit,   Customer
Equipment  placed  in the  Space  shall not  interfere  with or  impair  service
provided  by  Winstar  or by  any  other  lessee  of  the  Premises;  shall  not
unreasonably  disturb any other  lessee of the  Premises;  shall not endanger or
damage the facilities of Winstar or of any authorized  user of the Space, or the
Premises;  shall not  compromise the privacy of any  communications  carried in,
from,  or through the  Premises;  and shall not create an  unreasonable  risk of
injury  or  death  to  any  individual  or to the  public.  Customer  shall  not
improperly restrict or interfere with Winstar's network or the use thereof. Upon
notice by Winstar, Customer shall promptly remove any hazard,  interference,  or
service  obstruction  that may be caused by hardware,  software or  connectivity
owned by or under the  control  of  Customer.  Nothing  stated  herein  shall be
construed  to  interfere  with  Customer's  ability  to comply  with the  rules,
regulations  or directives of any  governmental  or judicial  authority.  In the
event that the  Customer  improperly  restricts  or  interferes  with  Winstar's
network, or the use thereof, Winstar may, after giving

                                       41
<PAGE>

Customer notice,  immediately modify,  suspend, delay, condition, or cease until
cured its obligations under this Exhibit in whole or in part.

     (f) Winstar shall not arbitrarily or  discriminatorily  require Customer to
relocate the Customer  Equipment;  however,  upon sixty (60) days prior  written
notice or, in the event of an emergency, such time as may be reasonable, Winstar
reserves the right to change the location of the Space or the Terminal  Facility
to a site  which  shall  afford  comparable  environmental  conditions  for  the
Customer  Equipment  and  comparable  accessibility  to the Customer  Equipment.
Winstar and Customer will work together in good faith to minimize any disruption
to  Customer's  services  as a  result  of such  relocation.  Winstar  shall  be
responsible for the cost of improving the Space to which the Customer  Equipment
may be relocated,  and for relocation of Customer  Equipment  interconnected  to
Winstar  services,  except that Winstar shall not be responsible  for relocating
facilities installed in violation of this Section 4.

6. Insurance.  Customer agrees to maintain,  at Customer's  expense,  during the
entire time this Agreement is in effect for each Space (i) Comprehensive General
Liability   Insurance   in  an  amount  not  less  than  One   Million   Dollars
($1,000,000.00)  per  occurrence  for bodily  injury or  property  damage,  (ii)
Employers  Liability  in an amount not less than Five Hundred  Thousand  Dollars
($500,000.00) per occurrence,  and (iii) Workers'  Compensation in an amount not
less than that prescribed by statutory limits.  Prior to taking occupancy of the
Space,  Customer  shall furnish  Winstar with  certificates  of insurance  which
evidence the minimum levels of insurance set forth herein and which name Winstar
as an additional insured.

7. Covenants,  Representations  and Warranties.  Each Party covenants and agrees
that  it  has  or  shall   obtain  any  and  all  rights,   licenses,   permits,
authorizations,  consents and  approvals  (including,  without  limitation,  any
necessary  local,  state,  federal or tribal  authorizations  and  environmental
permits) as are  reasonably  necessary in order to permit them to perform  their
obligations hereunder.

                    (THIS SPACE IS INTENTIONALLY LEFT BLANK)

                                       42
<PAGE>

IN WITNESS  WHEREOF,  the Parties hereto have caused this Exhibit to be executed
by their duly authorized representatives.

SAVVIS COMMUNICATIONS                         WINSTAR WIRELESS, INC.
 CORPORATION

By:                                           By:
      -----------------------------------          -----------------------------

Name:                                         Name:
      -----------------------------------          -----------------------------

Title:
      -----------------------------------     Title:
                                                    ----------------------------

Date:                                         Date:
      -----------------------------------          -----------------------------

                                       43
<PAGE>

                          COLLOCATION SCHEDULE NO. E-1

This Collocation Schedule is made on this ______ day of ____________,  2000 (the
"Effective  Date") and subject to all definitions,  terms and conditions of that
certain Exhibit for Terminal Facility  Collocation Space,  dated ________,  2000
the ("Master Agreement") by and between Winstar Wireless,  Inc., ("Winstar") and
SAVVIS  Communications  Corp.  ("Customer")  accepts and  ratifies the terms and
conditions  of the  Master  Agreement,  with  respect to the  Terminal  Facility
identified below, as specifically set forth herein.

1.   Address of Terminal Facility Location:

2.   Space.
     (as applicable)
     Cabinet(s): ___________________________

     Shelves: ______________________________

3.   Requested Service Date: __________

4.   Escort Services

     Escort Service is ____REQUIRED  ____NOT REQUIRED each time Customer obtains
     access to the Terminal Facility.

SAVVIS COMMUNICATIONS                               WINSTAR WIRELESS, INC.
 CORPORATION

By:                                       By:
     ----------------------------------         --------------------------------

Name:                                     Name:
     ----------------------------------         --------------------------------

Title:                                    Title:
     ----------------------------------         --------------------------------

Date:                                     Date:
     ----------------------------------         --------------------------------

                                       44
<PAGE>

                                  ATTACHMENT 1

                         To Collocation Schedule No. E-1

                                FACILITY DRAWINGS

                                       45
<PAGE>

                          COLLOCATION SCHEDULE NO. E-2

                       In-Building Installation Guidelines

Savvis will buy, and Winstar will install a wireless OC3 link between the Savvis
requested location and the Winstar hub site. The Wireless OC3 link shall consist
of a clear channel OC-3 connection.

For Option 1a - OC3 Distributed via Stinger:

     o    Winstar   will   connect   the  OC3   radio's   indoor   unit  to  the
          Savvis-provided Lucent Stinger via fiber, as specified by Savvis.

     o    Winstar  will  provide  appropriate  power  and  rack  space  for  the
          Savvis-provided Lucent Stinger(s) in support of SAVVIS customers.

     o    Winstar will provide the vertical distribution  utilizing a Category 5
          cable plant with  sufficient  capacity to insure service to all SAVVIS
          customers  within a given  building.  Winstar will terminate the cable
          plant  utilizing  standard  110  punch-down  blocks to every 3rd floor
          location  from top to bottom of building.  Winstar will  maintain this
          vertical cable.

     o    Savvis  will  connect  from the 110  blocks to the  customer  station.
          Savvis will install and maintain this horizontal cable.

     o    The cable  plant can and must be shared by both  entities  and must be
          able to service all Savvis customers as defined by an SLA.

For Option 1b - OC3 - Bulk Pipe To Single Customer/Floor:

     o    Winstar will install and terminate a 6-pair multimode fiber cable from
          the radio  indoor unit to the  nearest  telephone  closet  serving the
          customer.  This fiber run will be installed in appropriate  protective
          conduit and terminated in appropriate light-guide termination panel.

For Option 2:

     o    If  Winstar  has  space  in it's  existing  building  cabinet  for the
          Savvis-provided   Lucent   Stinger,   then  Winstar  will,  at  Savvis
          discretion, make every effort to utilize that space for Savvis Stinger
          deployment.

For Option 3:

                                       46
<PAGE>

o        In a worst-case  scenario where Savvis wishes to provide service to its
         customer and there is no space  available  for it's  equipment - Savvis
         will utilize the Winstar  infrastructure to provide this service.  This
         option does not satisfy SAVVIS "lit building"  requirements  and should
         be used only at SAVVIS discretion.

                                       47
<PAGE>

                          COLLOCATION SCHEDULE NO. E-3

                                   PRICE LIST

Central Office Collocation          $____ per month (2 racks @ $____ per rack)

"B" Site Collocation (DSLAM)        $____ per building per month

                                       48

<PAGE>

           CONFIDENTIAL MATERIALS HAVE BEEN OMITTED FROM THIS EXHIBIT
            PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT AND HAVE
             BEEN FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
                     COMMISSION. ASTERISKS DENOTE OMISSIONS.

                                     September 29, 2000

Mr. Bob Maguire
President - COO
Large Accounts
Winstar Wireless, Inc.
685 Third Avenue
31st Floor
New York, New York, 10017

Dear Bob:

On June 30,  2000,  SAVVIS  Communications  Corporation  ("SAVVIS")  and Winstar
Wireless,   Inc.   ("Winstar")   entered  into  a  series  of  agreements   (the
"Agreements")  pursuant to which SAVVIS and Winstar  agreed to purchase and sell
certain products and services  between them.  Among the Agreements  entered into
were a Master  Agreement  (the  "Master  Agreement"),  a  Professional  Services
Agreement  (the  "Professional  Services  Agreement"),  as  amended  and a Basic
Internet Services  Agreement (the "BSA").  Capitalized terms used herein and not
otherwise  defined shall have the meanings given to such terms in the Agreements
and  the  related  exhibits.  It is the  intent  of the  parties  to  amend  the
Agreements in accordance with the terms of this letter.

Pursuant to Exhibit A to the Master  Agreement - Equipment  Purchase,  SAVVIS is
obligated  to purchase 500 radios  pairs from  Winstar  during the Term.  SAVVIS
hereby agrees to  accelerate  the purchase of 106 radio pairs from Winstar as of
the date hereof as evidenced by the Purchase Order  attached  hereto as Schedule
A, such that  subsequent  to the date hereof,  SAVVIS shall have acquired 310 of
the 500 radio  pairs it is  obligated  to purchase  under the Master  Agreement.
SAVVIS shall be obligated to make payments with respect to such additional radio
pairs as set forth on Schedule A; provided,  however,  that in the event Winstar
has failed to install 175 radio pairs, which radio pairs have also been accepted
by SAVVIS on or before  October 1, 2001,  then  SAVVIS  shall  continue  to make
payments of [**] per quarter until such time as Winstar has installed and SAVVIS
has  accepted  175 radio  pairs.  At such time SAVVIS  shall  resume the payment
schedule  as set forth on Schedule  A,  provided  that in the event that the 175
radio pairs were not  installed and accepted by October 1, 2001 that amount paid
to Winstar  from  October 1, 2001 until the 175 radio pairs were  installed  and
accepted shall be offset against the future quarterly payment  obligations.  For
example, if the 175 radio pairs were not

<PAGE>

installed and accepted until February 10, 2002,  then the payment due to Winstar
on March 1, 2002 shall be [**] (being [**] minus [**]).

Section 3.2 of the Professional  Services  Agreement shall be amended to provide
that Winstar shall request Services from SAVVIS in a minimum amount of [**] (the
"Minimum") during calendar year 2001 which Services shall be provided to Winstar
at the rate of at least [**] per  quarter.  To the extent that  Winstar does not
use Services in an amount equal to at least [**] per quarter,  then SAVVIS shall
invoice Winstar and Winstar shall be obligated to pay such amounts. In the event
that  Winstar  fails to use  Services in the year 2001 in an amount equal to the
Minimum,  then SAVVIS shall invoice  Winstar at the end of calendar year 2001 in
an amount equal to the difference between the Minimum and that amount previously
billed by SAVVIS during calendar year 2001.

The parties  shall amend the BSA to provide  that  Winstar  shall  acquire  from
SAVVIS an additional [**] in Frame Services and IP Services at the prices as are
set forth in the BSA.  Such  amount  shall be prepaid to SAVVIS and shall be due
and owing to SAVVIS on October 2, 2000.

Section 6 of the Master Agreement shall be amended to provide that SAVVIS shall,
at its option,  have a right of offset with respect to any amounts due and owing
to Winstar for the  Equipment  if, and to the extent,  Winstar  fails to pay any
amounts to SAVVIS under the Professional Services Agreement.

The parties  agree that they shall amend the  Agreements  as set forth above but
that it is the intent of the parties that the amendments  described herein shall
be binding on the parties as of the date hereof.

Sincerely,
SAVVIS Communications Corporation
/s/ Matthew A. Fanning

By: Matthew A. Fanning
Its: Executive Vice President - Strategic Development & Business Planning

Winstar Wireless, Inc.
/s/ Bob Maquire

By: Bob Maquire
Its: President - COO Large Accounts

[**] CONFIDENTIAL TREATMENT REQUESTED

<PAGE>

SAVVIS

PURCHASE ORDER
--------------
                                            ------------------------------------
                                            SHIP TO: SAVVIS/MERIDIAN

----------------------------------------
PAYMENT TERMS :  PER CONTRACT               5160 SANDY LEWIS DRIVE
DELIVERY TERMS:  FOB SHIPPING POINT         FAIRFAX, VA 22033
SHIP DATE:  9/29/2000                       ATTN: JOHN GRIMSLY
----------------------------------------    (703) 503 2900
                                            ------------------------------------
<TABLE>
<CAPTION>

DESCRIPTION                                                    QTY       PRICE    EXTENDED
-----------                                                    ----      -----      PRICE
                                                                                    -----
<S>                                                           <C>       <C>       <C>
106 OC3 RADIOS
ODU ALTIUM OC3 38GHZ  NN TX LOW BAND                              27      [**]         [**]
ODU ALTIUM OC3 38GHZ  NN TX HIGH BAND                             27      [**]         [**]
ODU ALTIUM OC3 38GHZ  NN TX LOW BAND                              27      [**]         [**]
ODU ALTIUM OC3 38GHZ  NN TX HIGH BAND                             27      [**]         [**]
ODU ALTIUM OC3 38GHZ  NN TX LOW BAND                              26      [**]         [**]
ODU ALTIUM OC3 38GHZ  NN TX HIGH BAND                             26      [**]         [**]
ODU ALTIUM OC3 38GHZ  NN TX LOW BAND                              26      [**]         [**]
ODU ALTIUM OC3 38GHZ  NN TX HIGH BAND                             26      [**]         [**]
GABRIEL 1 FT ANTENNA  LOW PROFILE FOR ALTIUM                     106      [**]         [**]
GABRIEL 2FT ANTENNA LOW PROFILE FOR ALTIUM                       106      [**]         [**]
IDU ALTIUM OC3 MM ST NN                                          212      [**]         [**]
                                                   SUBTOTAL                            [**]
                                     (PRICE PER RADIO PAIR)                            [**]
TOTAL                                                                                  [**]
[**] CONFIDENTIAL TREATMENT REQUESTED
</TABLE>

<PAGE>

SAVVIS 3Q PURCHASE *
* All prices and payment terms are laid out in the contract

<TABLE>
<S>                                        <C>
        OC3 Price per contract                [**]

          Actual # of radio's                 [**]

             Actual amount                    [**]

           Down Payment 30%                   [**]
                 4Q00                         [**]
                 1Q01                         [**]
                 2Q01                         [**]
                 3Q01                         [**]
                 4Q01                         [**]
                 1Q02                         [**]
                 2Q02                         [**]
                 3Q02                         [**]
                 4Q02                         [**]
                 1Q03                         [**]
                 2Q03                         [**]
                 3Q03                         [**]
                 4Q03                         [**]
                 1Q04                         [**]
                 2Q04                         [**]
                 3Q04                         [**]
                 4Q04                         [**]
                 1Q05                         [**]
                 2Q05                         [**]
                 3Q05                         [**]
                 4Q05                         [**]
                 1Q06                         [**]
                 2Q06                         [**]
                 3Q06                         [**]
</TABLE>

[**] CONFIDENTIAL TREATMENT REQUESTEDCONVERSION AGREEMENT

      Conversion Agreement (this "Agreement") dated as of October 12, 2000, by
and among Interiors, Inc., a Delaware corporation (the "Company"),
Interiors.com, Inc., a Delaware corporation and wholly owned subsidiary of the
Company (the "Sub"), and Seaside Partners, L.P., a Delaware limited partnership
(the "Seaside").

      WHEREAS, Seaside is the record owner of 200,000 shares of Series B
Preferred Stock, par value $.001 per share, of the Company (the "Series B
Preferred Shares"), which accrues dividends at 8% per annum and is convertible
into shares of Class A Common Stock, par value $.001 per share, of the Company
("Class A Shares") at $2.35 per share;

      WHEREAS, Seaside is the record owner of the Class A Common Stock Purchase
Warrant dated January 22, 1999 to purchase 2,000,000 shares of Class A Common
Stock, par value $.001 per share ("Class A Shares") of the Company at $0.75 per
share (the "Interiors Warrant");

      WHEREAS, Seaside is the holder of a Convertible Promissory Note dated May
16, 2000 in the original principal amount of $1,000,000 (the "Interiors.com
Note"), which accrues interest at 8% per annum and is convertible into common
stock, par value $.01 per share, of Sub ("Sub Common Stock") at $1.00 per share;

      WHEREAS, William J. Ritger is the record owner of the Common Stock
Purchase Warrant dated May 16, 2000 to purchase 2,500,000 shares Sub Common
Stock at $1.00 per share (the "Interiors.com Warrant");

      WHEREAS, the Company desires to simplify its capital structure, remove the
accrual of dividends on the Series B Preferred Shares, remove the accrual of
interest on the Interiors.com Note and remove the overhang of the Interiors
Warrant and the Interiors.com Warrant.

      In consideration of the mutual promises and covenants contained in this
Agreement, the parties hereto agree as follows:

      1. Conversion of Securities. The transactions listed below are to be made
notwithstanding the terms of the individual securities and the agreements
governing them:

            a) Seaside hereby exercises the Interiors Warrant for $1,500,000
      resulting in the issuance to Seaside of 2,000,000 Class A Shares;
            b) Seaside hereby delivers 150,000 Series B Preferred Shares having
      a value of $1,500,000 to the Company as the purchase price for the
      Interiors Warrant;
            c) Seaside hereby converts its remaining 50,000 Series B Preferred
      Shares and $213,485.20 in accrued dividends on the Series B Preferred
      Shares through October 11, 2000 into Class A Shares at a conversion price
      of $2.35 per Class A Share, resulting in the issuance of 303,610 Class A
      Shares;
            d) The Interiors.com Note and $9,863.01 in accrued interest through
      June 30, 2000, are converted into Class A Shares at $0.25 per Class A
      Share, resulting in the issuance of 4,039,452 Class A Shares;
            e) The interest on the Interiors.com Note of subsequent to June 30,
      2000 is forgiven by Seaside; and
            f) The Interiors.com Warrant is hereby terminated.
<PAGE>

      2. Delivery of Shares. By October 18, 2000, the Company shall deliver to
Seaside a stock certificate representing the 2,303,610 Class A Shares received
from conversion of the securities pursuant to paragraphs 1. a) and 1 c) above,
and a second stock certificate representing the 4,039,452 Class A Shares
received from conversion of the securities pursuant to paragraph 1. d) above.

      3. Restriction on Transfer. Until March 31, 2001, Seaside shall not sell,
transfer, pledge, hypothecate or otherwise convey, directly or indirectly, any
interest in the Class A Shares being delivered pursuant to this Agreement.

      4. Standstill Agreement. (a) For so long as the Class A Shares are held by
Seaside or its affiliates, Seaside will not, alone or in concert with others,
directly or indirectly: (i) by purchase or otherwise, acquire, or agree to
acquire, ownership (including, but not limited to, beneficial ownership) of any
Class A Shares or direct or indirect rights (including convertible securities)
or options to acquire such ownership; (ii) make any public announcement with
respect to, or submit any proposal for, the acquisition of beneficial ownership
of Class A Shares (or direct or indirect rights, including convertible
securities, or options to acquire such beneficial ownership) for or with respect
to any extraordinary transaction or merger, consolidation, sale of substantial
assets or business combination involving the Company or any of its affiliates,
whether or not any parties other than Seaside or its affiliates and associates
are involved and whether or not such proposal might require the making of a
public announcement; (iii) make, or in any way participate in, any
"solicitation" of "proxies" (as such terms are defined or used in Regulation 14A
under the Exchange Act) or become a "participant" in any "election contest" (as
such terms are defined or used in Rule 14a-11 under the Exchange Act) to vote,
or seek to advise or influence any person or entity with respect to the voting
of, any voting securities of the Company or any of its affiliates; provided,
however, that the foregoing shall not restrict any actions with respect to
matters (other than matters relating to the election of directors or the
composition of the Company's Board of Directors) submitted to a shareholder vote
which matters are not proposed or initiated by Seaside or its affiliates or
associates or by any person acting in concert with or at the direction of
Seaside or its affiliates or associates; (iv) form, join or in any way
participate in a "group" (as such term is used in Section 13d(3) of the Exchange
Act) with respect to any securities of the Company in connection with any action
or matter otherwise prohibited by the terms of this agreement; (v) initiate or
propose any shareholder proposals for submission to a vote of shareholders with
respect to the Company or any of its affiliates or propose any person for
election to the Board of Directors of the Company or any of its affiliates; or
(vi) otherwise seek to control the management or policies of the Company or any
of its affiliates, including, without limitation, taking any action to seek to
obtain representation on the Board of Directors of the Company or any of its
affiliates.

      (b) So long as the Class A Shares are held by Seaside or its affiliates,
Seaside and its affiliates will vote the Class A Shares delivered pursuant to
this Agreement in support of the election of the nominees to the Company's Board
of Directors proposed by either the current Board of Directors or the members of
the Board of Directors who have been nominated to the Board by the current Board
of Directors (or such of their successors who have been nominated by the Board
members so nominated).

      5. Registration of the Class A Shares held by Seaside. The Company shall
make a reasonable best effort to have registered by March 31, 2001, all of the
Class A Shares issued pursuant to paragraph 1. a) and 1. c) of this Agreement
held by Seaside that are not then salable by Seaside under Rule 144.

      6. Miscellaneous.

                                       2
<PAGE>

      (a) This Agreement may be executed in several counterparts, each of which
shall be deemed an original, but all of which together shall constitute one and
the same instrument.

      (b) The headings and paragraphs of this Agreement have been added for
convenience only and shall not be deemed part of this Agreement.

      (c) The invalidity or unenforceability of any provision of this Agreement
shall not affect the validity or enforceability of any other provision.

      (d) This Agreement shall be governed by and construed in accordance with
the laws of the State of New York.

      (e) This Agreement sets forth the entire understanding and agreement of
the parties, and supersedes any and all oral or written agreements or
understandings between the parties, as to the subject matter hereof. If may be
changed only by a writing signed by all the parties hereto.

      IN WITNESS WHEREOF, the undersigned have hereunto set their hands as of
the day and year first above written.

                                        INTERIORS, INC.

                                        By: /s/
                                           -------------------------------------
                                           Name:  Max Munn
                                           Title: Chairman, President and Chief
                                                  Executive Officer

                                        INTERIORS.COM, INC.

                                        By: /s/
                                           -------------------------------------
                                           Name:  Max Munn
                                           Title: Chairman

                                        SEASIDE PARTNERS, L.P.

                                        By: SEASIDE ADVISORS, L.L.C.,
                                           -------------------------------------
                                           its general partner

                                        By: /s/
                                           -------------------------------------
                                           Name: William Ritger

                                        WILLIAM J. RITGER

                                        By: /s/
                                           -------------------------------------
                                           Name: William Ritger

                                       3

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