Exhibit 10.2

Separation Agreement and General Release

      This Separation Agreement and General Release (hereinafter “Agreement”) is
entered into by and between Advanced Switching Communications, Inc. (referred to
as “the Company”) and Ronald S. Westernik (referred to as “employee”), who are
collectively referred to herein as the “Parties.”

      WHEREAS, the Parties now desire and agree to forever sever their
employment relationship and to fully and finally resolve any and all existing or
potential issues, claims, causes of action, grievances and disputes without any
admission of liability or finding or admission that any of Employee’s rights,
under any statute, claim or otherwise, were in any way violated. In
consideration of the mutual promises contained herein, and other good and
valuable consideration as hereinafter recited, the receipt and adequacy of which
are hereby acknowledged, the Parties, intending to be legally bound, agree as
follows:

      1. Employee hereby acknowledges that the Company has notified him on July
23, 2001 (the “Notification Date”) that his employment with the Company will
cease on August 3, 2001 (the “Termination Date”) due to a reduction in force.
For a period commencing on the Notification Date and ending on July 27, 2001,
Employee agrees to continue in his current capacity and provide transitional
services. From July 28, 2001, through the Termination Date, Employee shall be on
paid administrative leave.

      Employee’s employment at the Company will end on the Termination Date.
Employee resigns from the Board of Directors effective August 3, 2001. Employee
recognizes that for purposes of the continuation coverage requirements of group
health plans under the Consolidated Omnibus Budget Reconciliation Act of 1985
(COBRA), as amended, and the group health provisions of any applicable state or
local law, a “qualifying event” occurs on Employee’s Termination Date.

      2. In exchange for the promises made by Employee herein and if Employee
executes and does not revoke this Agreement, the Company agrees to pay to
Employee, in addition to the one week of paid administrative leave described in
Paragraph 1 above, an amount equal to Employee’s base pay (i.e., Employee’s
bi-weekly salary) that Employee would have earned for one year, less all lawful
deductions, which shall be paid to Employee in accordance with the Company’s
normal payroll schedule over the fifty-two (52) week period from August 4, 2001,
to August 3, 2002 (the “Guaranteed Severance Period”). In addition, if Employee
is not employed or engaged in consulting services by the end of the Guaranteed
Severance Period, the Company will pay Employee an additional amount equal to
Employee’s base pay (i.e., Employee’s bi-weekly salary) that Employee would have
earned for six (6) months, less all lawful deductions, which shall be paid to
Employee in accordance with the Company’s normal payroll schedule over the
twenty-six (26) week period from August 4, 2002, to February 3, 2003 (the
“Contingent Severance Period”); provided, however, that the Company’s obligation
to make payments during the Contingent Severance Period will terminate on the
earlier of (i) February 3,

-1-

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

2003 and (ii) Employee’s employment of any kind or consulting arrangement with
another person or entity. Employee agrees to promptly notify Company if he
obtains any such employment or consulting arrangement that commences prior to
the end of the Contingent Severance Period. The Company agrees to begin making
the Guaranteed Severance payments to Employee within fourteen (14) days after
the “Effective Date,” as defined in paragraph 16, except that, in the event
Employee exercises his revocation rights under paragraph 15, the Company has no
obligation to make any of the severance payments described in this paragraph.

      3. Employee agrees that upon the Termination Date, he will surrender to
the Company every item and every document in Employee’s possession or control
that is the Company’s property (including but not limited to keys, records,
computers, peripherals, computer files and disks, notes, memoranda, models,
inventory and equipment) or contains Company information, in whatever form.
Employee acknowledges and stipulates that all of the Company’s electronic and
telephonic communication systems, computers and other business equipment
including, but not limited to, computer systems, data bases, phone mail, modems,
e-mail, Internet access, Web sites, fax machines, techniques, processes,
formulas, mask works, source codes, programs, semiconductor chips, processors,
memories, disc drives, tape heads, computer terminals, keyboards, storage
devices, printers and optical character recognition devices, and any and all
components, devices, techniques or circuitry incorporated in any of the above
and similar business devices (herein collectively referred to as Electronic
Equipment” ), are the sole property of the Company, and that any information
transmitted by, received from, or stored in such Electronic Equipment is also
the Company’s property. Employee agrees that, after his separation of employment
from the Company, he shall not, directly or indirectly, for himself or for any
other person or entity, use, access, copy, or retrieve, or attempt to use,
access, copy, or retrieve, any of the Company’s Electronic Equipment or any
information on the Company’s Electronic Equipment.

      4. All reference requests from Employee’s prospective employers shall be
made in writing addressed to the attention of Laurie Foglesong, Director of
Human Resources. In response to such requests, the Department of Human Resources
will provide to prospective employers Employee’s dates of employment and job
title. The Department of Human Resources will not provide any additional
information to prospective employers regarding Employee’s employment without
Employee’s written consent.

      5. The parties acknowledge that Employee’s entitlement to stock options of
the Company is governed by one or more stock option agreements (the “Option
Agreements”). The procedures and time restrictions for the exercise of vested
options are set forth in the Option Agreements. All unvested options previously
granted to Employee shall expire and terminate on the Termination Date. The
Company waives its repurchase rights with respect to 25% of Employees 300,000
shares of Company stock (that is

-2-

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

75,000 shares), which would otherwise be restricted until one year after the
closing of the Initial Public Offering per the Amendment to the Key Employee
Stock Agreement.

      6. Employee agrees that he is not otherwise entitled to the payments from
the Company described in Paragraph 2 above. Employee understands that by signing
this Agreement, he is electing to receive the payments described in paragraph 1
under the terms set forth in this Agreement.

      7. As of the date Employee signs this Agreement, Employee represents that
he has been paid for all hours worked through the date of his signature, and has
not suffered any on-the-job injury as of the date of his signature for which he
has not already filed a claim. As a part of this Agreement, the Company agrees
that all vacation pay, commissions, or overtime pay (if applicable) that he is
owed will be paid on August 31, 2001.

      8. Employee agrees that, in consideration of the additional payments
described in paragraph 1 herein, he will, and hereby does, forever and
irrevocably release and discharge the Company, and its past, present and future,
affiliates, parents, subsidiaries, divisions, predecessors, purchasers, assigns,
representatives and successors, and its and their officers, directors,
employees, independent contractors, agents, (herein collectively referred to as
the “Releasees”) from any and all claims, causes of action, damages, defenses,
promises, judgments, and liabilities, known or unknown, whatsoever which he now
has, has had, or may have, whether the same be at law, in equity, or mixed, in
any way arising from or relating to any act, occurrence, or transaction before
the date of this Agreement, including without limitation his employment and
separation of employment from the Company and any and all tax related
liabilities that may result from this Agreement. Employee expressly acknowledges
that this General Release includes, but is not limited to, Employee’s intent to
release the Company from tort and contract claims, wrongful discharge claims,
statutory claims, compensation claims, and claims of discrimination or
harassment based on age, race, color, sex, religion, handicap, disability,
national origin, ancestry, citizenship, marital status, retaliation or any claim
under the Age Discrimination In Employment Act (29 U.S.C. §§ 626 et seq.,
AADEA”), Title VII of the Civil Rights Acts of 1964 and 1991 as amended (42
U.S.C. §§ 2000e et seq.), Employee Retirement Income Security Act (29 U.S.C. §§
1001 et seq.), the Consolidated Omnibus Budget Reconciliation Act of 1985 (29
U.S.C. §§ 1161 et seq.), the Americans With Disabilities Act (42 U.S.C. §§ 12101
et seq.), the Rehabilitation Act of 1973 (29 U.S.C. §§ 701 et seq.), the Family
and Medical Leave Act (29 U.S.C. §§ 2601 et seq.), the Worker Adjustment and
Retraining Notification Act (29 U.S.C. §§ 2101 et seq.), and any other federal,
state or local law prohibiting employment discrimination or relating to the
employment relationship. This release does not include any claims that cannot be
waived by law. It is agreed and understood that this release is a GENERAL
RELEASE to be construed in the broadest possible manner consistent with
applicable law.

      9. Employee agrees not to make or file any lawsuits, complaints, or other
proceedings of any kind in any federal, state or municipal court against the
Company or

-3-

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

any of the Releasees concerning any claim that he has released in this
Agreement. Provided that, this Agreement and covenant not to sue does not
restrict Employee’s right to challenge the enforceability of this Agreement or
to file a charge with or participate in an investigation conducted by any
government agencies. Employee further agrees that no such lawsuits, complaints,
or other proceedings have already been made or filed by or on behalf of Employee
regarding any claims that have been released by this Agreement. Employee further
agrees and covenants not to assist or encourage others in making or filing any
lawsuits in any federal, state or municipal court against the Company or any of
the Releasees.

      10. Employee agrees that the additional severance payments provided for in
this Agreement shall not be construed as an admission of any wrongdoing or
liability on the part of the Company and that any such wrongdoing or liability
is expressly denied. Employee represents that he has not assigned or transferred
to any person or entity any claim against the Company and that any such claim is
not assignable or transferable. The Parties agree that this Agreement shall be
governed by Virginia law, and that the state and/or federal courts in Virginia
shall have sole and exclusive jurisdiction and venue to hear any dispute
concerning this Agreement. If any terms of the provisions of this Agreement are
found null, void or inoperative, for any reason, the remaining provisions will
remain in full force and effect. The language of all parts of this Agreement
shall in all cases be construed as a whole, according to its fair meaning, and
not strictly for or against either of the Parties.

      11. The Parties agree that this Agreement contains and comprises the
entire agreement and understanding of the Parties, that there are no additional
promises or terms of the Agreement among the Parties other than those contained
herein, and that this Agreement shall not be modified except in a writing signed
by each of the Parties hereto. This Agreement cancels and supersedes any prior
employment agreements or arrangements that Employee may have entered into with
the Company or any of the Releasees, except that the terms of paragraphs 6 and 7
of Employee’s Key Employee Employment Agreement and the Option Agreement(s) (to
the extent applicable for vested options) entered into by Employee and Company
shall remain and continue in effect in accordance with the terms thereof.

      12. Employee agrees that he will not disclose or cause to be disclosed any
negative, adverse or derogatory comments or information about the Company, about
any product or service provided by the Company, or about the Company’s prospects
for the future, except as required by law. Furthermore, Employee hereby
represents to the Company that he has made no such communication to any public
official, to any person associated with the media, or to any other person or
entity. Employee acknowledges that the Company relies upon this representation
in agreeing to enter into this Agreement.

      13. Employee represents that he has read this Agreement, that he
understands all of its terms, that in executing this Agreement he does not rely
and has not relied upon

-4-

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

any representation or statements made by any of the Company’s agents,
representatives, or attorneys with regard to the subject matter, basis, or
effect of the Agreement, and that he enters into this Agreement voluntarily, of
his own free will, without any duress and with knowledge of its meaning and
effect. Employee acknowledges that he has been and is advised by the Company to
consult an attorney prior to executing the Agreement.

      14. Employee understands that he has forty five (45) days from the date of
his receipt of this Agreement, which was July 23, 2001, to sign it, and that he
may unilaterally waive this period at his election. Employee’s signature on this
Agreement constitutes an express waiver of the forty-five (45) day period if
affixed prior to the expiration of that period. By signing this Agreement,
Employee expressly acknowledges that his decision to sign this Agreement was
knowing and voluntary and of his own free will. The Parties agree that any
revisions or modifications to this Agreement, whether material or immaterial,
will not and did not restart this time period.

      15. Employee acknowledges that he may revoke this Agreement for up to and
including seven (7) days after his execution of this Agreement, and this
Agreement regarding his release of claims shall not become effective until the
Effective Date as defined in paragraph 16. Employee agrees that, in order to be
effective, his revocation pursuant to this Paragraph must be delivered in
writing to Sherry Rhodes before 5:00 p.m. on the seventh day following
Employee’s execution of this Agreement.

      16. This Agreement shall become effective on the eighth day following the
date on which Employee signs it, unless Employee revokes it (“Effective Date”).

      17. Employee understands that his termination is the result of a reduction
in force, which is occurring on or about July 20, 2001. All individuals who are
being terminated in the reduction in force will be eligible for severance
payments based upon their execution of a release identical to this one. By
signing this Agreement, Employee acknowledges that he has received Exhibit A,
which sets forth the job titles and ages of other individuals whose employment
will be terminated as a result of the reduction in force and the ages of the
individuals in the same job classification or organizational unit who were not
selected for termination on that date.

      18. Employee also acknowledges that the Company may require him to provide
assistance to the Company in the investigation and/or defense of potential or
actual claims, charges or legal actions against the Company and agrees to
provide the requested assistance, which may include, but is not limited to,
interview(s), affidavit(s) and/or in person testimony. Employee acknowledges
that such requests may come during and/or after his Guaranteed Severance Period
and Contingent Severance Period and agrees to provide the assistance as and when
required. If Employee no longer resides in the Washington, D.C. metropolitan
area when his assistance is required and it is necessary that he be present in
the metropolitan area to provide that assistance, the Company will pay his
reasonable travel and related expenses for such period as his

-5-

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

presence is required but will not pay for his time spent either traveling or
rendering such assistance or for any lost income.

      IN WITNESS WHEREOF, the parties have duly executed this Agreement as of
the day and year first written above.

      /s/ Ronald S. Westernik

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

Ronald S. Westernik 7/26/1

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

Date   /s/ Sherry L.Rhodes

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

For: Advanced Switching Communications, Inc. 7/26/01

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

Date

-6-