<PAGE>

                                                                   EXHIBIT 10.28
                   AMERICAN INDUSTRIAL REAL ESTATE ASSOCIATION

                                STANDARD SUBLEASE

                 (Long form to be used with pre-1996 AIR leases)

      1. PARTIES. This Sublease, dated, for reference purposes only, October 7,
2002, is made by and between Inter-Tel Technologies, Inc. ("SUBLESSOR") and
Vixel Corporation ("SUBLESSEE").

      2. PREMISES. Sublessor hereby subleases to Sublessee and Sublessee hereby
subleases from Sublessor for the term, at the rental, and upon all of the
conditions set forth herein, that certain real property, including all
improvements therein, and commonly known by the street address of 10 Faraday,
Suite 200 located in the County of Orange, State of California, and generally
described as (describe briefly the nature of the property) the whole second
floor of the 2-story, R&D building at 10 Faraday, Irvine, 92618 ("Premises").

      3. TERM.

         3.1 TERM. The term of this Sublease shall be for two (2) years, seven
(7) months commencing on December 1, 2002 and ending on June 30, 2005 unless
sooner terminated pursuant to any provision hereof.

         3.2 DELAY IN COMMENCEMENT. Sublessor agrees to use its best
commercially reasonable efforts to deliver possession of the Premises by the
commencement date. If, despite said efforts, Sublessor is unable to deliver
possession as agreed, Sublessor shall not be subject to any liability therefor,
nor shall such failure affect the validity of this Sublease. Sublessee shall
not, however, be obligated to pay Rent or perform its other obligations until it
receives possession of the Premises. If possession is not delivered within sixty
days after the commencement date, Sublessee may, at its option, by notice in
writing within ten days after the end of such sixty day period, cancel this
Sublease, in which event the Parties shall be discharged from all obligations
hereunder, If such written notice is not received by Sublessor within said ten
day period, Sublessee's right to cancel shall terminate. Except as otherwise
provided, if possession is not tendered to Sublessee when required and Sublessee
does not terminate this Sublease, as aforesaid, any period of rent abatement
that Sublessee would otherwise have enjoyed shall run from the date of delivery
of possession and continue for a period equal to what Sublessee would otherwise
have enjoyed under the terms hereof, but minus any days of delay caused by the
acts or omissions of Sublessee. If possession is not delivered within 120 days
after the commencement date, this Sublease shall automatically terminate unless
the Parties agree, in writing, to the contrary.

      4. RENT.

         4.1 BASE RENT. Sublessee shall pay to Sublessor as Base Rent for the
Premises equal monthly payments of $8,333.33 in advance, on the 1st day of each
month of the term hereof. Sublessee shall pay Sublessor upon the execution
hereof $8,333.33 as Base Rent for December 1, 2002 (See also addendum section
14). Base Rent for any period during the term hereof which is for less than one
month shall be a pro rata portion of the monthly installment.

         4.2 RENT DEFINED. All monetary obligations of Sublessee to Sublessor
under the terms of this Sublease (except for the Security Deposit) are deemed to
be rent ("RENT"). Rent shall be payable in lawful money of the United States to
Sublessor at the address stated herein or to such other persons or at such other
places as Sublessor may designate in writing.

      5. SECURITY DEPOSIT. Sublessee shall deposit with Sublessor upon execution
hereof $25,000.00 as security for Sublessee's faithful performance of
Sublessee's obligations hereunder. If Sublessee fails to pay Rent or other
charges due hereunder, or otherwise defaults with respect to any provision of
this Sublease, Sublessor may use, apply or retain all or any portion of said
deposit for the payment of any Rent or other charge in default or for the
payment of any other sum to which Sublessor may become obligated by reason of
Sublessee's default, or to compensate Sublessor for any loss or damage which
Sublessor may suffer thereby. If Sublessor so uses or applies all or any portion
of said deposit, Sublessee shall within ten days after written demand therefore
forward to Sublessor an amount sufficient to restore said Deposit to the full
amount provided for herein and Sublessee's failure to do so shall be a material
breach of this Sublease. Sublessor shall not be required to keep said Deposit
separate from its general accounts. If Sublessee performs all of Sublessee's
obligations hereunder, said Deposit, or so much thereof as has not therefore
been applied by Sublessor, shall be returned, without payment of Interest to
Sublessee (or at Sublessor's option, to the last assignee, if any, of
Sublessee's interest hereunder) at the expiration of the term hereof, and after
Sublessee has vacated the Premises. No trust relationship is created herein
between Sublessor and Sublessee with respect to said Security Deposit.

      6. USE.

         6.1 AGREED USE. The Premises shall be used and occupied only for
general office use and for no other purpose.

         6.2 COMPLIANCE. Sublessor warrants that the improvements on the
Premises comply with all applicable covenants or restrictions of record and
applicable building codes, regulations and ordinances ("APPLICABLE
REQUIREMENTS") in effect on the commencement date. Said warranty does not apply
to the use to which Sublessee will put the Premises or to any alterations or
utility installations made or to be made by Sublessee. NOTE: Sublessee is
responsible for determining whether or not the zoning is appropriate for its
intended use, and acknowledges that past uses of the Premises may no longer be
allowed. If the Premises do not comply with said warranty, Sublessor shall,
except as otherwise provided, promptly after receipt of written notice from
Sublessee setting forth with specificity the nature and extent of such
non-compliance, rectify the same at Sublessor's expense. If Sublessee does not
give Sublessor written notice of a non-compliance with this warranty within six
months following the commencement date, correction of that non-compliance shall
be the obligation of Sublessee at its sole cost and expense. If the Applicable
Requirements are hereafter changed so as to require during the term of this
Sublease the construction of an addition to or an alteration of the Building,
the remediation of any Hazardous Substance, or the reinforcement or other
physical modification of the Building ("CAPITAL EXPENDITURE"), Sublessor and
Sublessee shall allocate the cost of such work as follows:

         (a) If such Capital Expenditures are required as a result of the
specific and unique use of the Premises by Sublessee as compared with uses by
tenants in general, Sublessee shall be fully responsible for the cost thereof
provided, however, that if such Capital Expenditure is required during the last
two years of this Sublease and the cost thereof exceeds six months' Base Rent,
Sublessee may instead terminate this Sublease unless Sublessor notifies
Sublessee in writing, within ten days after receipt of Sublessees's termination
notice that Sublessor has elected to pay the difference between the actual cost
thereof and the amount equal to six months' Base Rent. If the Parties elect
termination, Sublessee shall immediately cease the use of the Premises which
requires such Capital Expenditure and deliver to Sublessor written notice
specifying a termination date at least ninety days thereafter. Such termination
date shall, however, in no event be earlier then the last day that Sublessee
could legally utilize the Premises without commencing such Capital Expenditure.

                                  Page 1 of 4
<PAGE>
         (b) If such Capital Expenditure is not the result of the specific and
unique use of the Premises by Sublessee (such as governmentally mandated seismic
modifications, then Sublessor shall pay for said Capital Expenditure and the
cost thereof shall be prorated between the Sublessor and Sublessee and Sublessee
shall only be obligated to pay, each month during the remainder of the term of
this Sublease, on the date on which Rent is due, an amount equal to the product
of multiplying the cost of such Capital Expenditure by a fraction, the numerator
of which is one, and the denominator of which is the number of months of the
useful life of such Capital Expenditure as such useful life is specified
pursuant to Federal income tax regulations or guidelines for depreciation
thereof (including interest on the unamortized balance as is then commercially
reasonable in the judgment of Sublessor's accountant), with Sublessee reserving
the right to prepay its obligation at any time. Provided, however, that if such
Capital Expenditure is required during the last two years of this Sublease or if
Sublessor reasonably determines that it is not economically feasible to pay its
share thereof, Sublessor shall have the option to terminate this Sublease upon
ninety days prior written notice to Sublessee unless Sublessee notifies
Sublessor, in writing, within ten days alter receipt of Sublessor's termination
notice that Sublessee will pay for such Capital Expenditure. If Sublessor does
not elect to terminate, and fails to tender its share of any such Capital
Expenditure, Sublessee may advance such funds and deduct same, with interest,
from Rent until Sublessor's share of such costs have been fully paid. If
Sublessee is unable to finance Sublessor's share, or if the balance of the Rent
due and payable for the remainder of this Sublease is not sufficient to fully
reimburse Sublessee on an offset basis, Sublessee shall have the right to
terminate this Sublease upon ten days written notice to Sublessor.

         (c) Notwithstanding the above, the provisions concerning Capital
Expenditures are intended to apply only to non-voluntary, unexpected, and new
Applicable Requirements. If the Capital Expenditures are instead triggered by
Sublessee as a result of an actual or proposed change in use, change In
intensity of use, or modification to the Premises then, and in that event,
Sublessee shall be fully responsible for the cost thereof, and Sublessee shall
not have any right to terminate this Sublease.

         6.3 ACCEPTANCE OF PREMISES AND LESSEE. Sublessee acknowledges that:

         (a) it has been advised by Brokers to satisfy itself with respect to
the condition of the Premises (including but not limited to the electrical, HVAC
and fire sprinkler systems, security, environmental aspects, and compliance with
Applicable Requirements), and their suitability for Sublessee's intended use,

         (b) Sublessee has made such investigation as it deems necessary with
reference to such matters and assumes all responsibility therefor as the same
relate to its occupancy of the Premises, and

         (c) neither Sublessor, Sublessor's agents, nor any Broker has made any
oral or written representations or warranties with respect to said matters other
than as set forth in this Sublease.

In addition, Sublessor acknowledges that:

         (a) Broker has made no representations, promises or warranties
concerning Sublessee's ability to honor the Sublease or suitability to occupy
the Premises, and

         (b) it is Sublessor's sole responsibility to investigate the financial
capability and/or suitability of all proposed tenants.

      7. MASTER LEASE

         7.1 Sublessor is the lessee of the Premises by virtue of a lease,
hereinafter the "MASTER LEASE", a copy of which is attached hereto marked
Exhibit 1, wherein 10 Faraday Partners, a California general partnership is the
lessor, hereinafter the "MASTER LESSOR"

         7.2 This Sublease is and shall be at all times subject and subordinate
to the Master Lease.

         7.3 The terms, conditions and respective obligations of Sublessor and
Sublessee to each other under this Sublease shall be the terms and conditions of
the Master Lease except for those provisions of the Master Lease which are
directly contradicted by this Sublease in which event the terms of this Sublease
document shall control over the Master Lease. Therefore, for the purposes of
this Sublease, wherever in the Master Lease the word "Lessor" is used it shall
be deemed to mean the Sublessor herein and wherever in the Master Lease the word
"Lessee" is used it shall be deemed to mean the Sublessee herein.

         7.4 During the term of this Sublease and for all periods subsequent for
obligations which have arisen prior to the termination of this Sublease,
Sublessee does hereby expressly assume and agree to perform and comply with, for
the benefit of Sublessor and Master Lessor, each and every obligation of
Sublessor under the Master Lease except for the following paragraphs which are
excluded therefrom: Sections 7.1(b), 7.1(c), 10.2, and 11.

         7.5 The obligations that Sublessee has assumed under paragraph 7.4
hereof are hereinafter referred to as the "SUBLESSEE'S ASSUMED OBLIGATIONS". The
obligations that Sublessee has not assumed under paragraph 7.4 hereof are
hereinafter referred to as the "SUBLESSOR'S REMAINING OBLIGATIONS".

         7.6 Sublessee shall hold Sublessor free and harmless from all
liability, judgments, costs, damages, claims or demands, including reasonable
attorneys fees, arising out of Sublessee's failure to comply with or perform
Sublessee's Assumed Obligations.

         7.7 Sublessor agrees to maintain the Master Lease during the entire
term of this Sublease, subject, however, to any earlier termination of the
Master Lease without the fault of the Sublessor, and to comply with or perform
Sublessor's Remaining Obligations and to hold Sublessee free and harmless from
all liability, judgments, costs, damages, claims or demands arising out of
Sublessor's failure to comply with or perform Sublessor's Remaining Obligations.


         7.8 Sublessor represents to Sublessee that the Master Lease is in full
force and effect and that no default exists on the part of any Party to the
Master Lease.

     8.  ASSIGNMENT OF SUBLEASE AND DEFAULT.
         8.1 Sublessor hereby assigns and transfers to Master Lessor the
Sublessor's interest in this Sublease, subject however to the provisions of
Paragraph 8.2 hereof.

         8.2 Master Lessor, by executing this document, agrees that until a
Default shall occur in the performance of Sublessor's Obligations under the
Master Lease, that Sublessor may receive, collect and enjoy the Rent accruing
under this Sublease. However, it Sublessor shall Default in the performance of
its obligations to Master Lessor then Master Lessor may, at its option, receive
and collect, directly from Sublessee, all Rent owing and to be owed under this
Sublease. Master Lessor shall not, by reason of this assignment of the Sublease
nor by reason of the collection of the Rent from the Sublessee, be deemed liable
to Sublessee for any failure of the Sublessor to perform and comply with
Sublessor's Remaining Obligations.

         8.3 Sublessor hereby irrevocably authorizes and directs Sublessee upon
receipt of any written notice from the Master Lessor stating that a Default
exists in the performance of Sublessor's obligations under the Master Lease, to
pay to Master Lessor the Real due and to become due under the Sublease.
Sublessor agrees that Sublessee shall have the right to rely upon any such
statement and request from Master Lessor, and that Sublessee shall pay such Rent
to Master Lessor without any obligation or right to inquire as to whether such

                                  Page 2 of 4
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Default exists and notwithstanding any notice from or claim from Sublessor to
the contrary and Sublessor shall have no right or claim against Sublessee for
any such Rent so paid by Sublessee.

         8.4 No changes or modifications shall be made to this Sublease without
the consent of Master Lessor.

      9. CONSENT OF MASTER LESSOR.

      9.1 In the event that the Master Lease requires that Sublessor obtain the
consent of Master Lessor to any subletting by Sublessor then, this Sublease
shall not be effective unless, within ten days of the date hereof, Master Lessor
signs this Sublease thereby giving its consent to this Subletting.

         9.2 In the event that the obligations of the Sublessor under the Master
Lease have been guaranteed by third parties then neither this Sublease, nor the
Master Lessor's consent, shall be effective unless, within 10 day of the date
hereof, said guarantors sign this Sublease thereby giving their consent to this
Sublease.

         9.3 In the event that Master Lessor does give such consent then:

            (a) Such consent shall not release Sublessor of its obligations or
alter the primary liability of Sublessor to pay the Rent and perform and comply
with all of the obligations of Sublessor to be performed under the Master Lease.


            (b) The acceptance of Rent by Master Lessor from Sublessee or anyone
else liable under the Master Lease shall not be deemed a waiver by Master Lessor
of any provisions of the Master Lease.

            (c) The consent to this Sublease shall not constitute a consent to
any subsequent subletting or assignment.

            (d) In the event of any Default of Sublessor under the Master Lease,
Master Lessor may proceed directly against Sublessor, any guarantors or anyone
else liable under the Master Lease or this Sublease without first exhausting
Master Lessor's remedies against any other person or entity liable thereon to
Master Lessor.

            (e) Master Lessor may consent to subsequent sublettings and
assignments of the Master Lease or this Sublease or any amendments or
modifications thereto without notifying Sublessor or anyone else liable under
the Master Lease and without obtaining their consent and such action shall not
relieve such persons from liability.

            (f) In the event that Sublessor shall Default in its obligations
under the Master Lease, then Master Lessor, at its option and without being
obligated to do so, may require Sublessee to attorn to Master Lessor in which
event Master Lessor shall undertake the obligations of Sublessor under this
Sublease from the time of the exercise of said option to termination of this
Sublease but Master Lessor shall not be liable for any prepaid Rent nor any
Security Deposit paid by Sublessee, nor shall Master Lessor be liable for any
other Defaults of the Sublessor under the Sublease.

         9.4 The signatures of the Master Lessor and any Guarantors of Sublessor
at the end of this document shall constitute their consent to the terms of this
Sublease.

         9.5 Master Lessor acknowledges that, to the best of Master Lessor's
knowledge, no Default presently exists under the Master Lease of obligations to
be performed by Sublessor and that the Master Lease is in full force and effect.

         9.6 In the event that Sublessor Defaults under its obligations to be
performed under the Master Lease by Sublessor, Master Lessor agrees to deliver
to Sublessee a copy of any such notice of default. Sublessee shall have the
right to cure any Default of Sublessor described in any notice of default within
ten days after service of such notice of default on Sublessee. If such Default
is cured by Sublessee then Sublessee shall have the right of reimbursement and
offset from and against Sublessor.

     10. BROKERS FEE

         10.1     Intentionally omitted.

                  Per separate agreement.

         10.2 Sublessor agrees that if Sublessee exercises any option or right
of first refusal as granted by Sublessor herein, or any option or right
substantially similar thereto, either to extend the term of this Sublease, to
renew this Sublease, to purchase the Premises, or to lease or purchase adjacent
property which Sublessor may own or in which Sublessor has an interest, then
Sublessor shall pay to Broker a fee in accordance with the schedule of Broker in
effect at the time of the execution of this Sublease. Notwithstanding the
foregoing, Sublessor's obligation under this Paragraph 10.2 is limited to a
transaction in which Sublessor is acting as a Sublessor, lessor or seller.

         10.3 Master Lessor agrees that if Sublessee shall exercise any option
or right of first refusal granted to Sublessee by Master Lessor in connection
with this Sublease, or any option or right substantially similar thereto, either
to extend or renew the Master Lease, to purchase the Premises or any part
thereof, or to lease or purchase adjacent property which Master Lessor may own
or in which Master Lessor has an interest, or if Broker Is the procuring cause
of any other lease or sale entered into between Sublessee and Master Lessor
pertaining to the Premises, any part thereof, or any adjacent property which
Master Lessor owns or in which it has an interest, then as to any of said
transactions, Master Lessor shall pay to Broker a fee, in cash, in accordance
with the schedule of Broker in effect at the time of the execution of this
Sublease.

         10.4 Any fee due from Sublessor or Master Lessor hereunder shall be due
and payable upon the exercise of any option to extend or renew, upon the
execution of any new lease, or, in the event of a purchase, at the close of
escrow.

         10.5 Any transferee of Sublessor's interest in this Sublease, or of
Master Lessor's interest in the Master Lease, by accepting an assignment
thereof, shall be deemed to have assumed the respective obligations of Sublessor
or Master Lessor under this Paragraph 10. Broker shall be deemed to be a
third-party beneficiary of this paragraph 10.

     11. ATTORNEY'S FEES. If any party or the Broker named herein brings an
action to enforce the terms hereof or to declare rights hereunder, the
prevailing party in any such action, on trial and appeal, shall be entitled to
his reasonable attorney's lees to be paid by the losing party as fixed by the
Court,

     12.  Intentionally omitted.
         See additional provisions in addendum.


                                  Page 3 of 4
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ATTENTION: NO REPRESENTATION OR RECOMMENDATION IS MADE BY THE AMERICAN
INDUSTRIAL REAL ESTATE ASSOCIATION OR BY ANY REAL ESTATE BROKER AS TO THE LEGAL
SUFFICIENCY, LEGAL EFFECT, OR TAX CONSEQUENCES OF THIS SUBLEASE OR THE
TRANSACTION TO WHICH IT RELATES. THE PARTIES ARE URGED TO:

l. SEEK ADVICE OF COUNSEL AS TO THE LEGAL AND TAX CONSEQUENCES OF THIS SUBLEASE.

2. RETAIN APPROPRIATE CONSULTANTS TO REVIEW AND INVESTIGATE THE CONDITION OF THE
PREMISES. SAID INVESTIGATION SHOULD INCLUDE BUT NOT BE LIMITED TO: THE POSSIBLE
PRESENCE OF HAZARDOUS SUBSTANCES, THE ZONING OF THE PROPERTY, THE STRUCTURAL
INTEGRITY, THE CONDITION OF THE ROOF AND OPERATING SYSTEMS, AND THE SUITABILITY
OF THE PREMISES FOR SUBLESSEE'S INTENDED USE.

WARNING: IF THE SUBJECT PROPERTY IS LOCATED IN A STATE OTHER THAN CALIFORNIA,
CERTAIN PROVISIONS OF THE SUBLEASE MAY NEED TO BE REVISED TO COMPLY WITH THE
LAWS OF THE STATE IN WHICH THE PROPERTY IS LOCATED.
<TABLE>
<S>                                                                          <C>

Executed at:  Irvine, CA
              ----------------------------------------------------------     -----------------------------------


on:  Nov. 4, 2002                                                            By  /s/  David Krietzberg
     -------------------------------------------------------------------     -----------------------------------
Address:  10 Faraday                                                         By  David Krietzberg
        ----------------------------------------------------------------     -----------------------------------
                                                                             "Sublessor" (Corporate Seal)



Executed at:  Bothell, WA
             -----------------------------------------------------------     -----------------------------------


on:  November 1, 2002                                                        By  /s/  Kurtis L. Adams
     -------------------------------------------------------------------     -----------------------------------
Address:  1191 North Creek Parkway                                           By   Kurtis L. Adams
        ----------------------------------------------------------------     -----------------------------------
                 Bothell, WA  98011                                          "Sublessee" (Corporate Seal)



Executed at:
             -----------------------------------------------------------     -----------------------------------


on:                                                                          By
     -------------------------------------------------------------------     -----------------------------------
Address:                                                                     By
       ----------------------------------------------------------------      -----------------------------------
                                                                             "Master Lessor" (Corporate Seal)
</TABLE>
NOTE: THESE FORMS ARE OFTEN MODIFIED TO MEET CHANGING REQUIREMENTS OF LAW AND
NEEDS OF THE INDUSTRY. ALWAYS WRITE OR CALL TO MAKE SURE YOU ARE UTILIZING THE
MOST CURRENT FORM: AMERICAN INDUSTRIAL REAL ESTATE ASSOCIATION, 700 SO. FLOWER
ST., SUITE 600, LOS ANGELES, CA 90017, (213)687-8777.




                                  Page 4 of 4
<PAGE>
      ADDENDUM FOR SUBLEASE BY AND BETWEEN INTER-TEL TECHNOLOGIES, INC., AS
                 SUBLESSOR AND VIXEL CORPORATION, AS SUBLESSEE,
                                OCTOBER 31, 2002

                                     Page 1

13.   "AS-IS" CONDITION. Sublessee shall take the Premises in an "as-is",
      present condition, except for Sublessor's cleaning of the ceiling tiles
      and air filters visual to the eye on a onetime basis, by no later than the
      lease commencement date. Any and all tenant improvements to the Premises
      are to be performed solely by the Sublessee, subject to the prior written
      consent by the Sublessor and Master Lessor. Sublessee shall take full
      responsibility for determining the suitability of the Premises, including
      but not limited to its compliance with any and all applicable building
      codes including the American with Disabilities Act ("ADA"). If the
      Premises must be altered in order to comply with ADA at any time during
      the term of the sublease, either Sublessor or Sublessee has the option to
      terminate the sublease rather than make the changes if the changes include
      the installation of an elevator or other major structural modifications.

14.   BASE RENT. Base rent as referenced in section 4.1 of the Sublease shall be
      full service gross, flat for the term, except that Sublessee shall
      separately meter and be responsible for any and all electricity costs in
      connection with the air conditioning unit used to cool the server room to
      be installed by the Sublessee, and the Sublessee shall be responsible for
      paying its prorata share of operating expense increases over the 2003 base
      year.

15.   OPERATING EXPENSE INCREASE. Sublessee shall pay to Sublessor during the
      term hereof, in addition to the Base Rent, Sublessee's Share of the amount
      by which all Operating Expenses for each Comparison Year exceeds the
      amount of all Operating Expenses for the Base Year, such excess being
      hereinafter referred to as the "Operating Expense increase", in accordance
      with the following provisions.

     (a) "BASE YEAR" is 2003.

     (b) "COMPARISON YEAR" is defined as each calendar year during the term of
     this Lease subsequent to the Base Year; provided, however, Sublessee shall
     have no obligation to pay a share of the Operating Expense Increase
     applicable to the first 12 months of the Lease Term. Sublessee's Share of
     the Operating Expense Increase for the first and last Comparison Years of
     the Lease Term shall be prorated according to that portion of such
     Comparison Year as to which Sublessee is responsible for a share of such
     increase.

     (c) "OPERATING EXPENSES" include all costs incurred by Sublessor
     relating to the operation of the Building calculated as if the Building was
     at least 95% `occupied, including, but not limited to, the following:

            (i) The operation, repair, and maintenance in neat, clean, safe,
      good order and condition, but not the replacement (see subparagraph (g)),
      of the following:

               (aa) The Common Areas, including their surfaces, coverings,
     carpets, drapes and window coverings, and including parking areas, loading
     and unloading areas, trash areas, roadways, sidewalks, walkways, stairways,
     parkways, driveways, landscaping areas, striping, bumpers, irrigation
     systems, Common Area lighting facilities, building exteriors and roofs,
     fences and gates.

               (bb) All heating, air conditioning, plumbing, electrical systems,
     life safety equipment, communication systems and other equipment used in
     common by, or for the benefit of Sublessee or occupants of the Building,
     including fire detection systems including sprinkler system maintenance and
     repair.
<PAGE>
      ADDENDUM FOR SUBLEASE BY AND BETWEEN INTER-TEL TECHNOLOGIES, INC., AS
                 SUBLESSOR AND VIXEL CORPORATION, AS SUBLESSEE,
                                OCTOBER 31, 2002

                                     Page 2


            (ii) Trash disposal, janitorial and security services, pest control
      services, and the costs of any environmental inspections;

            (iii) Any other service to be provided by Sublessor that is
      elsewhere in the Master Lease stated to be an `Operating Expense";

            (iv) The cost of premiums for the insurance policies maintained by
      Sublessor pursuant to applicable paragraphs in the Master Lease.

            (v) The amount of the Real Property Taxes payable by Sublessor
      pursuant to applicable paragraphs in the Master Lease;

            (vi) The costs of water, sewer, gas, electricity, and other publicly
      mandated services not separately metered;

            (vii) Labor, salaries, and applicable fringe benefits and costs,
      materials, supplies and tools, used in maintaining and/or cleaning the
      Building and accounting and management fees attributable to the operation
      of the Building.

            (viii) The cost of any Capital Expenditure to the Building or the
      Building covered under the applicable paragraphs in the Master Lease;

     (d) Any item of Operating Expense that is specifically attributable to the
     Premises, the Building or to any other building in the Building or to the
     operation, repair and maintenance thereof, shall be allocated entirely to
     such Premises, Building or other building,

      (e) Sublessee's Share of Operating Expense Increase shall be payable by
      Sublessee within 30 days after a reasonably detailed statement of actual
      expenses presented to Sublessee by Sublessor. At Sublessor's option,
      however, an amount may be estimated by Sublessor from time to time in
      advance of Sublessee's Share of Operating Expenses Increase for any
      Comparison Year, and the same shall be payable monthly during each
      Comparison Year of the Lease term, on the same day as the Base Rent is due
      hereunder. In the even that Sublessee pay Sublessor's estimate of
      Sublessee's Share of Operating Expense Increase as aforesaid, Sublessor
      shall deliver to Sublessee within 60 days after the expiration of each
      Comparison year a reasonably detailed statement showing Sublessee's Share
      of the actual Operating Expense Increase incurred during such year. If
      Sublessee's payments under this paragraph (e) during said Comparison Year
      exceed Sublessee's Share as indicated on said statement, Sublessee
      payments shall be entitled to credit the amount of such overpayment
      against Sublessee's Share as indicated on said statement, Sublessee shall
      pay to Sublessor the amount of the deficiency within thirty (30) days
      after delivery by Sublessor to Sublessee of said statement. Sublessor and
      Sublessee shall forthwith adjust between them by cash payment any balance
      determined to exist with respect to that portion of the last Comparison
      Year for which Sublessee is responsible as to Operating Expense Increase,
      notwithstanding that the Lease term may have terminated before the end of
      such Comparison Year.

      (f) Operating Expenses shall not include the costs of replacement for
      equipment or capital components such as the roof, foundations, exterior
      walls or a Common Area capital improvement, such as the parking lot
      paving, elevators, fences that have a useful life for accounting purposes
      of 5 years or more unless it is the type describe in paragraph 4.2(c)
      (viii), in which case their cost shall be included as above provided.

      Operating Expenses shall not include any expenses paid by any tenant
      directly to third parties, or as to which Sublessor is otherwise
      reimbursed by any thing party, other tenant, or by insurance proceeds.
<PAGE>


      ADDENDUM FOR SUBLEASE BY AND BETWEEN INTER-TEL TECHNOLOGIES, INC., AS
                 SUBLESSOR AND VIXEL CORPORATION, AS SUBLESSEE,
                                OCTOBER 31, 2002

                                     Page 3


16.   UTILITIES AND SERVICES.

16.1 SERVICES PROVIDED BY SUBLESSOR. Sublessor shall provide heating,
ventilation, air conditioning, reasonable amounts of electricity for normal
lighting and office machines, water for reasonable and normal drinking and
lavatory use in connection with an office, and the provision of replacement
light bulbs and/or fluorescent tubes and ballasts, not the labor to replace, the
standard overhead fixtures. Sublessor shall also provide janitorial services to
the Premises and Common Areas 3 limes per week, excluding Building Holidays as
defined in the Master Lease. Sublessor shall not, however, be required to
provide janitorial services to the shower included within the Premises, and any
such additional janitorial service shall be at the sole cost and responsibility
of Sublessee.

16.2 SERVICES EXCLUSIVE TO SUBLESSEE. Sublessee shall be responsible for the
payment of any and all telephone service to the Premises including any cost of
installation of said service or equipment.

16.3 HOURS OF SERVICE. Sublessee shall have access to its Premises seven (7)
days per week, twenty-four (24) hours per day.

16.4 EXCESS USAGE BY SUBLESSEE. Sublessee shall not make connection to the
utilities except by or through existing outlets and shall not install or use
machinery or equipment in or about the Premises that uses excess water, lighting
or power, or suffer or permit any act that causes extra burden upon the
utilities and services, including but not limited to security and trash
services, over standard office usage for the Building. Sublessor shall require
Sublessee to reimburse Sublessor for any excess expenses or costs that may arise
out of a breach of this subparagraph by Sublessee. Sublessor may, provided it is
commercially reasonable, install at Sublessee's expense supplemental equipment
and/or separate metering applicable to Sublessee's excess usage or loading.

17. SERVER ROOM.

17.1 SERVER ROOM MODIFICATIONS. Sublessee shall be required to pay for all of
the costs associated with setting up a room within its Premises to contain its
server and other telephony and computer equipment (hereinafter referred to as
"Server Room"), including but not limited to designing and engineering,
permitting, installing equipment and modifying ducting to said Server Room.
Prior to undertaking physical work on the Server Room, Sublessee shall have
secured permits by the appropriate local city government authorities, and shall
give Sublessor advance written notice of its plans. Any work on the Server Room
shall be completed in a substantial, good and workmanlike manner to Sublessor's
and Master Lessor's satisfaction.

In the event Sublessee shall not make such Server Room modifications in the
manner required herein, or shall fail to make modifications deemed necessary by
the Master Lessor, Sublessor or local municipal building authority, Sublessee
shall be responsible for any and all sums expended by Master Lessor or Sublessor
to bring the improvements into compliance. In addition, the Sublessee shall be
responsible for returning the Server Room to its original condition at the time
the Sublessee vacates the Premises. In the event Sublessee fails to bring the
server room back to its original condition,
<PAGE>
      ADDENDUM FOR SUBLEASE BY AND BETWEEN INTER-TEL TECHNOLOGIES, INC., AS
                 SUBLESSOR AND VIXEL CORPORATION, AS SUBLESSEE,
                                OCTOBER 31, 2002

                                     Page 4

Sublessee shall be responsible for any and all sums expended by Master Lessor or
Sublessor to return the server room to its original condition.

18. INTERRUPTIONS. There shall be no abatement of rent and Sublessor shall not
be liable in any respect whatsoever for the inadequacy, stoppage, interruption
or discontinuance of any utility or service due to riot, strike, labor dispute,
breakdown, accident, repair or other cause beyond Sublessor's reasonable control
or in cooperation with governmental request or directions.

19. EARLY ACCESS. Notwithstanding any other provision of this Sublease,
Sublessor hereby grants Sublessee, (including Sublessee's employees, agents and
contractors) a non-exclusive, revocable license to enter into and upon Premises
from the date of execution of this Sublease and Master Lessor's consent to and
including the Commencement Date ("License") in order that Sublessee may: (1)
inspect, test and analyze the Premises and any Building system or components,
(2) prepare Sublessee's plans to shampoo the carpet, paint the Premises, build
the Server Room, install any Sublessee-specific security system, and (3) perform
any of the work as detailed above. Notwithstanding the above, the Commencement
Date shall not be extended or postponed due to any delay experienced by the
Sublessee to prepare or complete the work described above.

20. PARKING.

20.1 SUBLESSOR'S EXCLUSIVE PARKING. Sublessor shall have the right to use on an
exclusive basis the first four (4) spaces closest to the front door on the left
side of the parking lot (north side).

20.2 EXCESS PARKING. Pursuant to Provision 1.2 of the master lease, Sublessee
shall rights to use up to 29 parking spaces of the 58 total parking spaces
attributable to the Building. In the event that parking spaces over and above
the 29 spaces are not in use by the Sublessor, Sublessee shall have rights to
use on an as as-available, first come, first serve daily basis only; no
additional rights to park above the 29 parking space limit shall be assumed or
implied.

21. SIGNAGE. Sublessee shall have rights to install a monument sign at the
entrance to the Building's parking lot on the right side opposite the
Sublessor's monument sign, and on the front entrance to the Building, provided
that the following circumstances are satisfied: 1) Both signs shall be equal to
or smaller in scale and size than the equivalent signs of the Sublessor, 2) Both
signs shall be designed, permitted, made, installed and removed at the
expiration of the Sublease, at the sole cost and expense of the Sublessee, and
3) Both signs shall be subject to the prior written approval of the City of
Irvine and/or any other government authority over signage, the Sublessor and the
Master Lessor, 4) Installations and removals of both signs shall be completed in
a substantial, good and workmanlike manner to the Sublessor's and Master
Lessor's satisfaction.
<PAGE>
      ADDENDUM FOR SUBLEASE BY AND BETWEEN INTER-TEL TECHNOLOGIES, INC., AS
                 SUBLESSOR AND VIXEL CORPORATION, AS SUBLESSEE,
                                OCTOBER 31, 2002

                                     Page 5


22. COUNTERPART. This sublease shall not be effective until signed by both
parties and Master Lessor consents in writing to the sublease. The sublease and
consent documents may be executed in counterpart and a fax signature shall have
the same force and effect as an original.

<TABLE>
<S>                                                           <C>

Executed at:  Irvine, CA
              ---------------------------------------         ------------------------------------------------

On:  Nov. 4, 2002                                             By  /s/  David Krietzberg
     ------------------------------------------------             --------------------------------------------
Address:  10 Faraday                                          By  David Krietzberg
          -------------------------------------------             --------------------------------------------
                                                              Sublessor    VP Finance & CFO

Executed at:  Bothell, WA
              ---------------------------------------         ------------------------------------------------

On:  November 1, 2002                                         By  /s/  Kurtis L. Adams
     ------------------------------------------------             --------------------------------------------
Address:  1191 North Creek Parkway So.                        By  Kurtis L. Adams, CFO
          -------------------------------------------             --------------------------------------------
                 Bothell, WA  98011                           Sublessee

Executed at:
            -----------------------------------------         ------------------------------------------------

On:                                                           By
   --------------------------------------------------           ----------------------------------------------
Address:                                                      By
        ---------------------------------------------           ----------------------------------------------
                                                              Master Lessor
</TABLE>