Document:

Exhibit 10.5.3

                                    Amendment

      This Amendment is effective as of the signature date of the second party
to sign (the "Effective Date"), and amends the Agreement made as of July 25,
2002 (the "Agreement") by and between Visual Networks of Texas, L.P. ("Systems
Provider") and MCI WorldCom Network Services, Inc., for itself and its
Affiliates (collectively, "MCI"). Capitalized terms used but not defined in this
Amendment have the meanings assigned to them in the Agreement.

The parties hereby agree as follows:

1. With respect to Products ordered by MCI after the Effective Date, Paragraph
number 3 of the Agreement is deleted in its entirety and replaced with the
following:

      "Payment in full for all Products delivered by Systems Provider pursuant
      to this Agreement, as amended, must be received by Systems Provider within
      thirty (30) calendar days after the Product delivery date. MCI shall be
      entitled to take an additional discount of 2 percent (2%) off of the total
      amount of Systems Provider's invoice for invoices paid in full within
      fifteen (15) calendar days after Product delivery date. If Systems
      Provider does not receive payment when due under this Agreement, as
      amended, Systems Provider shall have no obligation to ship additional
      Products."

2. Paragraph 6 of the Agreement is hereby deleted in its entirety.

3. Unless explicitly modified herein, all terms and conditions of the Agreement
remain in full force and effect.

4. The parties agree that for all purposes of the Agreement and the
Reseller/Integrator Agreement referred to therein, the corporate name "MCI
WorldCom Network Services, Inc." shall be substituted for "MCI
Telecommunications Corporation" under which MCI was formerly doing business.

      Therefore, the parties have caused this Amendment to be executed by their
duly authorized representatives.

VISUAL NETWORKS                           MCI WORLDCOM NETWORK
OF TEXAS, L.P.                            SERVICES, INC.

By: /s/ Jefferson D. Norton               By: /s/ B. R. Bagby
   ------------------------------            ----------------------------

Name: Jefferson D. Norton                 Name: B. R. Bagby
     ----------------------------              --------------------------

Title: Associate General Counsel          Title:      Director
      ---------------------------               -------------------------

Date: August 28, 2002                     Date:  August 28, 2002
     ----------------------------              --------------------------Exhibit 10.37

                        OEM-IN SOFTWARE LICENSE AGREEMENT
                           (with Reproduction Rights)

       THIS OEM SOFTWARE LICENSE AGREEMENT, including the Exhibits
("Agreement"), effective as of December 3, 2002 ("Effective Date"), is hereby
made by and between Cisco Systems, Inc., a California corporation, having
principal offices at 170 West Tasman Drive, San Jose, California 95134-1706
(Cisco Systems, Inc. referred to herein as "Cisco") and Visual Networks
Operations, Inc., a Delaware corporation, having principal offices at 2092
Gaither Road, Rockville, Maryland, 20850 ("Licensor").

      For good and valuable consideration, the receipt and sufficiency of which
is hereby acknowledged, the parties agree as follows:

1. SOFTWARE.

      1.1 Software. Licensor hereby licenses to Cisco the Licensor software
products described in Exhibit B, as it may be amended from time to time in
accordance with the terms hereof (the "Software"). The Software includes copies
of software provided on disks or other media or provided electronically, user
documentation, packaging and any enhancements, modifications, updates, bug
fixes, releases, patents, patent rights, copyrights, trade secrets, know-how and
other intellectual property related thereto. The Software shall be provided by
Licensor in conformance with the functional, technical and other specifications
for the Software set forth in Exhibit B, as modified from time to time by
written agreement of the parties (the "Specifications").

      1.2 Additional; New Software Products. Current Licensor software not
listed on Exhibit A may be added upon mutual agreement by the parties of the
applicable price or royalties for such additional software, and any other terms
specific to such software, which shall be contained in an Addendum hereto.
Licensor shall keep Cisco informed of any new software products of Licensor.
Cisco will notify Licensor if it wishes to add new software products to this
Agreement. Cisco and Licensor shall then proceed to negotiate the applicable
price or royalties for such additional software, and any other terms specific to
such software, which shall be contained in an Addendum hereto. Upon reaching an
agreement on these items, such software shall be considered Software under this
Agreement and shall be licensed under the terms and conditions of this
Agreement.

      1.3 Upgrades. Licensor shall keep Cisco informed of all Software upgrades,
enhancements, improvements and bug fixes. Licensor shall make such items
available to Cisco no later than the date Licensor releases such items to any of
its other licensees and at no additional charge unless otherwise expressly
provided in this Agreement.

      1.4 Project Managers. Each party has appointed a single project manager
("Project Manager"). The names, addresses and telephone and fax numbers of the
Project Managers are attached to this Agreement as Exhibit C. The Project
Managers shall act as liaisons between the parties with respect to their
respective performance of this Agreement and shall provide the parties from time
to time with the names and telephone numbers of additional specific contact
persons (e.g., to communicate specific information regarding support,
enhancements, etc.) when such direct contact is preferable. In the event that
either party appoints a new Project Manager, such party will promptly notify the
other.

2. OWNERSHIP; GRANT OF RIGHTS

      2.1 Ownership. Licensor shall own all right, title, and interest in the
Software, including any modifications, enhancements, improvements or derivative
works thereof or thereto, made by Licensor or on behalf of Cisco by Licensor.

      2.2 License Grant. Subject to the terms of this Agreement, Licensor hereby
grants Cisco and its Affiliates (as defined below) a nonexclusive, worldwide,
irrevocable (subject to the termination provisions of this Agreement) perpetual
fee-bearing, non-transferable license, subject to the limitations contained
herein, to:

                                                                    Page 1 of 47
<PAGE>

            (a) use, manufacture and have manufactured, import, reproduce and
have reproduced, and embed or have embedded into Cisco products object code
copies of the Software;

            (b) copy, have copied, distribute, sell and offer to sell the
Software as stand-alone products or as incorporated into, or in connection with,
or for use with, any Cisco product by any means now known or developed in the
future in object code format in accordance with this Agreement, through multiple
tiers of distribution, including without limitation resellers, distributors,
VARS and OEMs ("Resellers"), to end users or directly to end users;

            (c) provide customer support (including, without limitation, to fix
Software bugs) pursuant to Section 7 below;

            (d) sublicense to end users, directly or indirectly, the right to
use the Software; and

            (e) for manufacturing purposes only, authorize the granting of
sublicenses of all of the license rights granted to Cisco and its Affiliates in
this Section 2.2.

"Affiliates" shall mean, with respect to any Person, any other Person who is
directly or indirectly controlling, controlled by or under common control with
such Person as of the Effective Date or thereafter. A Person shall be deemed to
be an Affiliate of another Person only so long as the foregoing control
relationship exists. For the purposes of this definition, the term "control",
when used with respect to any Person, means the possession, directly or
indirectly, of voting securities representing the right to elect a majority of
the Board of Directors (or other governing body) of such Person. "Person" means
an individual, corporation, partnership, association, trust or other entity or
organization.

      2.3 End User Restriction. Cisco shall, and shall require its Resellers to,
include an end user software license with each copy of the Software distributed
to a customer that is as protective as the form attached hereto as Exhibit I.
Cisco agrees to promptly notify Licensor of any known or suspected breach of the
software license with respect to the Software, and further agrees to, upon
Licensor's request, assign the claim to Licensor.

      2.4 Modification by Cisco. Neither Cisco nor its Resellers shall have the
right, to modify the Software without Licensor's express written consent;
provided, however, that Cisco shall have the right to modify the Software and
any end user documentation, or have the Software modified, for the purpose of
embedding the Software into Cisco products, and for branding purposes.
Furthermore, Cisco shall not reverse assemble, decompile, reverse engineer or
otherwise attempt to derive source code (or the underlying ideas, algorithms,
structure or organization) from Software, except as specifically authorized in
writing by Licensor. Except for the express licenses granted herein, no other
licenses are granted by implication, estoppel or otherwise.

      2.5 U.S. Government End Users. The Software and associated software
documentation qualify as "commercial items," as that term is defined at 48
C.F.R. 2.101, consisting of "commercial computer software" and "commercial
computer software documentation" as such terms are used in 48 C.F.R. 12.212.
Consistent with 48 C.F.R.12.212 and 48 C.F.R. 227.7202-1 through 227.7202-4,
Licensee will provide to Government end user, or, if this Agreement is direct
Government end user will acquire, the Software and software documentation with
only those rights set forth herein that apply to non-governmental customers. Use
of this Software and software documentation constitutes agreement by the
government entity that the computer software and computer software documentation
is commercial, and constitutes acceptance of the rights and restrictions herein.

      2.6 Cisco Property.

            (a) During the term of this Agreement Cisco may provide equipment,
designs, materials, software and other property of Cisco (collectively "Cisco
Property") to Licensor for its use in fulfilling its obligations hereunder. All
Cisco Property furnished to Licensor by Cisco or paid for by Cisco in connection
with this Agreement shall (i) be clearly marked or tagged as the property of
Cisco; (ii) be and remain personal property;

                                                                    Page 2 of 47
<PAGE>

(iii) be subject to inspection by Cisco at any time; (iv) be used only to
provide Software to Cisco and Cisco's authorized subcontractors, if any; (v) be
kept free of liens and encumbrances; (vi) be kept separate from other materials,
tools, or property of Licensor or held by Licensor; and (vii) not be modified in
any manner by Licensor.

            (b) Cisco shall retain all rights, title and interest in the Cisco
Property, and Licensor shall treat and maintain the Cisco Property with the same
degree of care as Licensor uses with respect to its own valuable equipment, but
in no event with less than a reasonable degree of care for equipment of a
similar kind and importance. Licensor shall bear all risk of loss or damage to
Cisco Property until it is returned to Cisco. Upon Cisco's request, Licensor
shall deliver all Cisco Property to Cisco in good condition, normal wear and
tear excepted, without cost to Cisco (exclusive of freight costs); the parties
shall determine the manner and procedure for returning the Cisco Property, and
Cisco shall pay the corresponding freight costs. Licensor waives any legal or
equitable right it may have to withhold Cisco Property, and Licensor shall
execute all documents, or instruments evidencing Cisco's ownership of the Cisco
Property as Cisco may from time to time request.

      2.7 Certain Patent Rights. Licensor hereby grants to Cisco and its
Affiliates, and the customers, distributors or manufacturers of Cisco or Cisco's
Affiliates a nonexclusive, perpetual, irrevocable, fully-paid, royalty-free, and
worldwide license under all of Licensor's patent rights to use, make, have make,
sell, offer for sale, and import the Suggested Enhancements (as defined in
Section 7.2 below), and incorporate it or combine it with other products and
services of any kind.

      2.8 [***]

3. FEES; PAYMENT; TAXES.

      3.1 Royalties and License Fees.

            (a) Subject to the terms and conditions of this Agreement, Cisco
shall pay Licensor the royalties and/or license fees in the amounts and on the
terms and conditions as specified in Exhibit A.

            (b) Licensor shall be obligated to pay all license fees and
royalties, if any, with respect to any third party proprietary rights and
technologies which are required for the exercise of Cisco's rights under this
Agreement.

      3.2 Payment Terms. Any payments required to be made by Cisco hereunder
shall be made in accordance with the terms set forth in Exhibit A.

      3.3 Taxes. The amounts paid pursuant to this Agreement are not subject to
sales and use tax. Cisco shall provide Licensor with satisfactory documentation
(including but not limited to resale exemption or other certificates) supporting
such status. All amounts payable by Cisco to Licensor pursuant to this Agreement
shall be net of international withholding taxes, and Cisco will provide Licensor
with written documentation (including but not limited to copies of receipts) of
any and all such withholding taxes paid in connection with such license fees and
royalties. All other items of tax based in whole or in part on the income of a
party shall be the sole responsibility of such party.

      3.4 Non-Revenue Uses. Cisco shall be entitled to use and copy the Software
free of charge for development and testing purposes, as well as for distribution
to Cisco's customers for evaluation purposes; provided, however, that if such
free Software copies are thereafter licensed to customers, Cisco shall pay
Licensor the license fee or royalty described in this Agreement. If requested by
Cisco, the parties will mutually agree to a one-time internal operational use
license fee that will entitle Cisco to unlimited internal operational use of the
Software.

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                    Page 3 of 47
<PAGE>

      3.5 [***]

4. DELIVERY OF MASTERS

      Pursuant to the license in Section 2.2, Licensor will provide to Cisco, at
no charge and in a format to be reasonably specified by Cisco, two (2) sets of
golden masters ("Software Masters") for all Software made available by Licensor
hereunder. The Software Masters will be in machine readable, binary form and
will include Software release documentation and will be shipped to Cisco within
(5) business days of first commercial availability, or the signing of an
addendum including such software hereunder. Additionally, Licensor will provide
beta versions of Software to Cisco for testing and evaluation purposes within
(5) business days of release to other beta testers and other
non-commercially-available versions of Software to Cisco for testing and
evaluation purposes as commercially reasonable.

5. SOFTWARE SPECIFICATIONS; CHANGES; DEPLOYMENT

      5.1 Specifications. Licensor shall make best commercially reasonable
efforts to provide Cisco with ninety (90) days' written notice of any intended
changes in the function, revision level, design or appearance of any Software or
to any specifications for any Software irrespective of impact on design or
function.

      5.2 Cisco's Change Request. When a design change is required by Cisco,
Cisco shall provide Licensor with written notice of all the documentation,
specifications and proposed effective date of such design change. Within fifteen
(15) days of receipt of such notice, Licensor shall advise Cisco in writing as
to the time frame, costs and pricing for implementation of such change.

      5.3 Interoperability Testing. Licensor shall perform such tests and
provide Cisco with the test results in accordance with the Interoperability and
Acceptance Testing Guidelines attached hereto as Exhibit D as modified from time
to time upon mutual written agreement of the parties. Cisco shall provide
Licensor with each Cisco product required for Licensor to perform such tests.
Licensor shall provide, at Cisco's request, all Licensor products, including
beta copies of Software or other Software not yet commercially available, so
that Cisco may perform its own interoperability testing.

      5.4 Marketing and Deployment. Licensor shall adhere to the marketing and
deployment guidelines set forth in Exhibit K.

6. END USER DOCUMENTATION AND TRADEMARKS

      6.1 End User Documentation. Licensor shall deliver end user documentation
in accordance with Exhibit E and hereby grants Cisco a worldwide, perpetual,
nonexclusive, non-transferable license to copy, have copied, modify, have
modified, incorporate and have incorporated and distribute all or any portion of
such end user documentation, provided such documentation is provided with, or in
association to, the Software, in accordance with this Agreement.

      6.2   Trademarks and Branding Guidelines. Cisco shall comply with
            Licensor's trademark and branding guidelines as set forth in Exhibit
            F.

      6.3   Quality Control. Cisco will present and promote the Software fairly
            and in compliance with all federal, state and local laws,
            regulations and ordinances. Cisco may accurately use Licensor's
            product names in Cisco's advertising and promotional media; provided
            (i) that Cisco conspicuously indicates in each such medium that such
            names are trademarks of Licensor, and (ii) that, as requested by
            Licensor from time to time, Cisco submits all such media to Licensor
            for prior approval and follows reasonable trademark usage guidelines
            communicated by Licensor.

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                    Page 4 of 47
<PAGE>

      6.4   Obligation Upon Termination or Expiration. Upon expiration or
            termination of this Agreement for any reason, Cisco will immediately
            cease all use of Licensor trademarks, marks, and trade names that
            Licensor may adopt from time to time and, at Licensor's election,
            either destroy or deliver to Licensor all materials in Cisco's
            control or possession which bear such marks or names.

      6.5   Trademarks. In connection with its rights hereunder, Cisco may use
            its name and any of its trademarks, trade names, logos and/or
            slogans or those of any third party in connection with the license,
            sublicense or distribution of the Software and any end-user
            documentation, marketing, or sales literature used with the
            Software. If Cisco contemplates the use or inclusion of a trademark,
            trade name, logo and/or slogan of a direct competitor of Licensor
            for a Cisco product which also contains the Software, Cisco will
            consult with Licensor regarding how to reasonably avoid inaccuracy
            or confusion as to the origin or ownership of the Software contained
            in such Cisco product.

      6.6   Copyright Notices. Cisco shall ensure that all copies of the
            Software in Cisco's possession or control incorporate copyright and
            other proprietary notices in the same manner that Licensor
            incorporates such notices in the Software and Documentation or in
            any manner reasonably requested by Licensor, subject to reasonable
            modifications or removals pursuant to Cisco's branding of the
            Software.

      6.7   Packaging. Unless otherwise requested by Cisco, packaging for the
            Software shall be Cisco's responsibility. Upon the request of Cisco,
            Licensor shall package the Software according to the Cisco standard
            packaging guidelines in effect at the time of the request. Within a
            reasonable time after the request for Licensor to package the
            Software, Cisco shall deliver its product packaging guidelines to
            Licensor. Cisco and Licensor shall thereafter mutually agree upon
            the price and the payment terms for such services.

7. SUPPORT

      7.1   Support. Licensor shall provide the support services described in
            Exhibit G on the terms and conditions set forth therein.

      7.2   Suggested Enhancements. Cisco shall communicate to Licensor its
            knowledge of any problems encountered with the Software or any
            modifications, design changes or improvements of the Software
            suggested by a customer of the Software ("Suggestions"). Cisco
            further agrees (i) that Licensor shall own all right, title and
            interest in and to any modifications, enhancements or improvements
            to the Software made by Licensor as the result of a Suggestion
            provided by Cisco ("Suggested Enhancements") , without the payment
            of any additional consideration thereof to Cisco and (ii) that, if
            applicable upon Licensor's reasonable request, it will cooperate
            with Licensor in connection with perfecting and enforcing Licensor's
            rights, title and interest to any Suggested Enhancements.

8. SOFTWARE ESCROW

      Upon execution hereof, the parties shall enter into an "Escrow Agreement"
in the form attached hereto as Exhibit H.

9. REPRESENTATIONS AND WARRANTIES

      9.1 Representations and Warranties of Licensor. Licensor hereby represents
and warrants to Cisco and its Affiliates as follows:

            (a) Licensor has the full power to enter into this Agreement, to
carry out its obligations under this Agreement and to grant the rights and
licenses granted to Cisco in this Agreement.

                                                                    Page 5 of 47
<PAGE>

            (b) For a period of [***], the Software will (i) perform
substantially in accordance with the applicable published or mutually agreed
upon specifications and related documentation provided by Licensor and
substantially achieve any function described therein and (ii) be free from
defects in materials, workmanship or design. Licensor will promptly correct or
replace (at its option) any defective Software. NO OTHER WARRANTIES ARE
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTIES OF QUALITY,
PERFORMANCE, NONINFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE. NOR ARE THERE ANY WARRANTIES CREATED BY A COURSE OF DEALING, COURSE OF
PERFORMANCE OR TRADE USAGE. LICENSOR DOES NOT WARRANT THAT THE SOFTWARE WILL
MEET CISCO'S NEEDS OR BE FREE FROM ERRORS, OR THAT THE OPERATION OF THE SOFTWARE
WILL BE UNINTERRUPTED. THE FOREGOING EXCLUSIONS AND DISCLAIMERS ARE AN ESSENTIAL
PART OF THIS AGREEMENT AND FORMED THE BASIS FOR DETERMINING THE FEES CHARGED FOR
THE SOFTWARE.

      9.2 Representations and Warranties of Cisco. Cisco hereby warrants and
represents to Licensor that Cisco has the full power to enter into this
Agreement and to carry out its obligations under this Agreement.

10. INDEMNIFICATION

      10.1 Indemnification by Licensor. Licensor shall defend, indemnify and
hold harmless Cisco and its Affiliates, officers, directors, employees,
shareholders, customers, agents, successors and assigns from and against any and
all loss, damages, liabilities, settlement, costs or expense (including legal
expenses and the expenses of other professionals) as incurred, resulting from or
arising out of (i) any claim of product liability in any way relating to the
Software; or (ii) any claim which alleges that any Software provided to Cisco
hereunder or the use, manufacture, import, service, support or distribution
thereof, all solely as authorized herein, infringes upon, misappropriates or
violates any trade secret under the laws of the United States, patent or
trademark under the laws of the United States, Canada or a member country of the
European Union and/or copyright under the laws of any adherent to the Berne
Convention of persons, firms or entities who are not parties to this Agreement.
As a condition to such defense and indemnification, Cisco will provide Licensor
with prompt written notice of the claim and permit Licensor to control the
defense, settlement, adjustment or compromise of any such claim. Cisco may
employ counsel at its own expense to assist it with respect to any such claim;
provided, however, that if such counsel is necessary because of a conflict of
interest of either Licensor or its counsel or because Licensor does not assume
control, Licensor will bear the expense of such counsel. Cisco shall have no
authority to settle any claim on behalf of Licensor.

      10.2 Licensor's Efforts. If the manufacture, use or distribution of the
Software is enjoined or becomes the subject of a claim of infringement, Licensor
shall use best commercially reasonable efforts at its option to: (i) obtain such
licenses; or (ii) make such replacements or modifications as are necessary to
the continue the manufacture, use or distribution of the Software without
infringement and in compliance with the specifications, if any, and
Documentation. If Licensor is unable to achieve either of the foregoing within
thirty (30) days (or such longer period as determined by Cisco in good faith)
after the holding of infringement or the entry of the injunction, as applicable,
Licensor shall promptly refund to Cisco the license fees or royalties paid for
any Software, the use, manufacture, import, support, service or distribution of
which is legally prohibited. Except to the extent reduced by payments described
in this paragraph, nothing in this paragraph shall limit any other remedy of
Cisco.

      10.3 Exceptions to Licensor Indemnity. Licensor shall have no obligation
under paragraphs 10.1 and 10.2 to the extent any claim of infringement or
misappropriation results from (i) use of the Software in combination with any
other product, end item, or subassembly not intended by Licensor if the
infringement would not have occurred but for such combination; (ii) any claim
based on Cisco's use of the Software after Licensor has informed Cisco of
modifications or changes in the Software required to avoid such claims and
offered to implement those modifications or changes, if such claim would have
been avoided by implementation of Licensor's suggestions; or (iii) use of the
Software other than as permitted under this Agreement, if the infringement would
not have occurred but for such use.

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                    Page 6 of 47
<PAGE>

11. CONFIDENTIALITY

      11.1 Agreement as Confidential Information. The parties shall treat the
terms and conditions and the existence of this Agreement as Confidential
Information. Each party shall obtain the other's consent prior to any
publication, presentation, public announcement or press release concerning the
existence or terms and conditions of this Agreement. The parties understand and
agree that, to the extent that either party is required to disclose the
existence of this Agreement or the terms hereof pursuant to any applicable law,
order or regulation of any government or regulatory entity, it is permitted to
do so, but each party shall to the extent reasonably possible, provide the other
party with prior notice and cooperate with the other party to limit or redact
the required disclosure.

      11.2 Confidential Information. The parties shall comply with the
provisions of the Non-Disclosure Agreement attached hereto as Exhibit J (the
"NDA"). To the extent that the term stated in the NDA terminates prior to the
termination of this Agreement, the parties agree that the term of the NDA shall
be automatically extended to the term of this Agreement.

12. LIMITATION OF LIABILITY

      EXCEPT AS PROVIDED UNDER SECTION 10 (INDEMNITY), UNDER NO CIRCUMSTANCES
WILL EITHER PARTY (WHICH IN THE CASE OF CISCO, INCLUDES AFFILIATES OF CISCO) BE
LIABLE TO THE OTHER UNDER ANY CONTRACT, STRICT LIABILITY, NEGLIGENCE OR OTHER
LEGAL OR EQUITABLE THEORY, FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOST
PROFITS IN CONNECTION WITH THE SUBJECT MATTER OF THIS AGREEMENT. THIS SECTION
DOES NOT LIMIT EITHER PARTY'S LIABILITY FOR BODILY INJURY OF A PERSON, DEATH, OR
PHYSICAL DAMAGE TO PROPERTY. THIS LIMITATION WILL APPLY NOTWITHSTANDING ANY
FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY PROVIDED HEREIN.

13. TERM AND TERMINATION

      13.1 Term. Unless terminated earlier as provided herein, this Agreement
shall commence on the Effective Date and end on January 31, 2004, unless
terminated sooner by written notice given by a party pursuant to this Section.
This Agreement shall be renewed automatically for additional successive one (1)
year periods, unless notice of non-renewal is given to the other no later than
sixty (60) days prior to the expiration of the initial term or then current
renewal term.

      13.2 Termination for Convenience. Cisco may terminate this Agreement at
any time for its convenience, for no reason or for any reason, upon delivery of
written notice to Licensor. In the event of such termination, Licensor shall be
entitled to receive and retain all License payments made or payable by Cisco in
accordance with Exhibit A and otherwise pursuant to this Agreement.

      13.3 Termination for Cause. This Agreement may be terminated by a party
for cause immediately upon the occurrence of and in accordance with the
following:

            (a) Insolvency Event. Either may terminate this Agreement by
delivering written notice to the other party upon the occurrence of any of the
following events: (i) a receiver is appointed for either party or its property;
(ii) either makes a general assignment for the benefit of its creditors; (iii)
either party commences, or has commenced against it, proceedings under any
bankruptcy, insolvency or debtor's relief law, which proceedings are not
dismissed within sixty (60) days; or (iv) either party is liquidated or
dissolved.

            (b) Change of Control. If there is a change in ownership
representing twenty percent (20%) or more of the equity ownership of a party,
the other party may, at its option, terminate this Agreement upon written notice
to the party undergoing such change in control.

            (c) Default. Either party may terminate this Agreement effective
upon written notice to the other if the other party violates any material
covenant, agreement, representation or warranty contained herein in

                                                                    Page 7 of 47
<PAGE>

any material respect or defaults or fails to perform any of its material
obligations or agreements hereunder in any material respect, which violation,
default or failure is not cured within thirty (30) days after notice thereof
from the non-defaulting party stating its intention to terminate this Agreement
by reason thereof. Possible material breaches by Cisco would include, but not be
limited to,: (i) reverse engineering of Software by Cisco; (ii) violation of the
license rights granted herein; or (iii) nonpayment of undisputed license and/or
support fees. Possible material breaches by Licensor would include, but not
limited to: (i) failure to provide support in accordance with Exhibit G hereto;
(ii) failure to perform interoperability testing, (iii) failure to comply with
the terms of the escrow agreement set forth in Exhibit H; or (iv) violation of
Licensor's confidentiality or indemnity obligations.

      13.4 Survival; Support After Termination. Sections 2.1, 2.3, 2.4, 2.5,
2.6, 2.7, 3, 6.4, 8, 9, 10, 11, 12, 13 and 14 shall survive termination or
expiration of this Agreement. Furthermore, in the event of any termination or
expiration of this Agreement (i) all end-user licenses shall remain in effect,
except to the extent that they are terminated pursuant to their own terms and
conditions; and (ii) Licensor shall continue to make available maintenance
support to Cisco at Licensor's prevailing rates for a minimum of two (2) years
after termination or expiration in accordance with Exhibit G.

Notwithstanding anything in the foregoing to the contrary, in the case of
termination by Cisco for cause pursuant to Section 13.3, all end user licenses
shall remain in effect and Cisco's license rights under Sections 2.2 shall
survive only for a period of six (6) months following such termination and only
with respect to Software then in inventory or subject to any pending purchase
order.

      13.5 Return of Materials Upon Termination. Within thirty (30) days after
the termination or expiration of this Agreement, Cisco will return or destroy
all sets of Software masters, all other copies of the Software, all
Documentation, Proprietary Information and other materials delivered or
furnished by or on behalf of Licensor to Cisco hereunder. Within thirty (30)
days after the termination or expiration of this Agreement, Licensor will return
or destroy all Proprietary Information and other materials delivered or
furnished by or on behalf of Cisco to Licensor hereunder. Cisco shall be
entitled to retain any required Licensor Confidential Information solely to
continue to support the Software.

14. MISCELLANEOUS

      14.1 Force Majeure. Neither party shall be liable to the other for delays
or failures in performance resulting from causes beyond the reasonable control
of that party, including, but not limited to, acts of God, labor disputes or
disturbances, material shortages or rationing, riots, acts of war, governmental
regulations, communication or utility failures, or casualties. In the event
Licensor fails to deliver any Software including without limitation, updates,
bug fixes or maintenance releases due to such causes, Cisco may terminate this
Agreement or any part hereof as to such Software not delivered. Licensor shall
resume performance under this Agreement immediately after the delaying cause
ceases and, at Cisco's option, extend the then current term period for a period
equivalent to the length of time the excused delay endured.

      14.2 Compliance with Laws. Each party agrees that in performance of its
obligations under this Agreement it shall comply with all applicable federal,
state, local laws and ordinances now or hereafter enacted.

      14.3 Import and Export. Cisco hereby acknowledges that the Software
supplied by Licensor under the Agreement is subject to export or import controls
under the laws and regulations of the United States (U.S.). Cisco shall comply
with such laws and regulations, and agrees not to knowingly export, re-export,
import or re-import or transfer Software without first obtaining all required
U.S. Government authorizations or licenses. Licensor and Cisco each agree to
provide the other information and assistance as may be reasonably required by
the other in connection with securing such authorizations or licenses, and to
take timely action to obtain all required support documents. Licensor shall
provide Cisco with information and assistance as may reasonably be required in
connection with executing import, export, sales, and trade programs, including
but not limited to, Manufacturer's Affidavits, Harmonized Tariff Schedule,
Export Control Classification Number, qualification information (eg. origin),
and U.S. Federal Communications Commission's identifier when applicable.

                                                                    Page 8 of 47
<PAGE>

      14.4 Relationship of Parties. The parties are independent contractors
under this Agreement and no other relationship is intended, including a
partnership, franchise, joint venture, agency, employer/employee, fiduciary,
master/servant relationship, or other special relationship. Neither party shall
act in a manner which expresses or implies a relationship other than that of
independent contractor, nor bind the other party.

Contractors of both parties shall comply with all applicable environmental
federal, state and local laws, regulations and ordinances, including but not
limited to the laws and regulations of the United States, relating to this
Agreement and the services and/or products provided hereunder. In the event that
a party's performance of its obligations under this Agreement requires the
delivery to or handling by the other party or the other party's contractors of
hazardous materials as specified in the U.S. Department of Transportation, Title
49 or OSHA standards or regulations, such party will promptly notify the other
party and upon request will provide the other party and affected contractors of
the other party with material safety data sheets and such other documentation
reasonably necessary for compliance with applicable laws and regulations.
Notwithstanding the foregoing, a party shall be fully responsible under this
Agreement for any liability resulting from its actions in supplying or
transporting hazardous materials or otherwise failing to comply with
environmental laws and regulations.

      14.5 No Third Party Beneficiaries. Unless otherwise expressly provided, no
provisions of this Agreement are intended or shall be construed to confer upon
or give to any person or entity other than Cisco and Licensor any rights,
remedies or other benefits under or by reason of this Agreement.

      14.6 Equitable Relief. Each party acknowledges that a breach by the other
party of any confidentiality or proprietary rights provision of this Agreement
may cause the non-breaching party irreparable damage, for which the award of
damages would not be adequate compensation. Consequently, the non-breaching
party may institute an action to enjoin the breaching party from any and all
acts in violation of those provisions, which remedy shall be cumulative and not
exclusive, and a party may seek the entry of an injunction enjoining any breach
or threatened breach of those provisions, in addition to any other relief to
which the non-breaching party may be entitled at law or in equity.

      14.7 Attorneys' Fees. In addition to any other relief awarded, the
prevailing party in any action arising out of this Agreement shall be entitled
to its reasonable attorneys' fees and costs.

      14.8 Notices. Any notice required or permitted to be given by either party
under this Agreement shall be in writing and shall be personally delivered or
sent by a reputable overnight mail service (e.g., Federal Express), to the
Project Manager of the other party. Notices will be deemed effective the next
business day after receipt by the party to be notified. A copy of any notice
shall be sent to the following:

        ---------------------------------------------------------------
        Cisco Systems, Inc.                Visual Networks
                                           Operations, Inc.
        ---------------------------------------------------------------
        170 West Tasman Drive              2092 Gaither Road
        ---------------------------------------------------------------
        San Jose, CA  95134                Rockville, MD 20850
        ---------------------------------------------------------------
        Attn: VP Legal Services and        Attn: Corporate Counsel
        General Counsel
        ---------------------------------------------------------------
        Fax:  (408) 526-7019               Fax (301) 296-2731
        ---------------------------------------------------------------

      14.9 Assignment. Except for Affiliates of Cisco, who are permitted
assignees of this Agreement, neither party may assign its rights or delegate its
obligations hereunder, either in whole or in part, whether by operation of law
or otherwise, without the prior written consent of the other party. Any
attempted assignment or delegation by a party without the written consent of the
other party will be void. The rights and liabilities of the parties under this
Agreement will bind and inure to the benefit of the parties' respective
successors and permitted assigns. For purposes of this Section, a twenty percent
(20%) change in control shall constitute an assignment.

      14.10 Waiver and Modification. Failure by either party to enforce any
provision of this Agreement will not be deemed a waiver of future enforcement of
that or any other provision. Any waiver, amendment or other modification of any
provision of this Agreement will be effective only if in writing and signed by
the parties.

                                                                    Page 9 of 47
<PAGE>

      14.11 Severability. If for any reason a court of competent jurisdiction
finds any provision of this Agreement to be unenforceable, that provision of the
Agreement will be enforced to the maximum extent permissible so as to effect the
intent of the parties, and the remainder of this Agreement will continue in full
force and effect.

      14.12 Controlling Law and Jurisdiction. This Agreement and any action
related thereto shall be governed, controlled, interpreted and defined by and
under the laws of the State of New York and the United States, without regard to
the conflicts of laws provisions thereof. The exclusive jurisdiction and venue
of any action with respect to the subject matter of this Agreement shall be the
state or federal courts of the State of New York and each of the parties hereto
submits itself to the exclusive jurisdiction and venue of such courts for the
purpose of any such action. The parties specifically disclaim the UN Convention
on Contracts for the International Sale of Goods.

      14.13 Headings. Headings used in this Agreement are for ease of reference
only and shall not be used to interpret any aspect of this Agreement.

      14.14 Entire Agreement. This Agreement, including all exhibits which are
incorporated herein by reference, constitutes the entire agreement between the
parties with respect to the subject matter hereof, and supersedes and replaces
all prior and contemporaneous understandings or agreements, written or oral,
regarding such subject matter. For the avoidance of doubt, this Agreement does
not replace or supercede the surviving terms of the Interoperability and
Marketing Agreement and/or the New World Ecosystem Program Agreement, each
between the parties hereto.

      14.15 Counterparts. This Agreement may be executed in two counterparts,
each of which shall be an original and together which shall constitute one and
the same instrument.

      14.16 Basis of Bargain. EACH PARTY RECOGNIZES AND AGREES THAT THE WARRANTY
DISCLAIMERS AND LIABILITY AND REMEDY LIMITATIONS IN THIS AGREEMENT ARE MATERIAL
BARGAINED FOR BASES OF THIS AGREEMENT AND THAT THEY HAVE BEEN TAKEN INTO ACCOUNT
AND REFLECTED IN DETERMINING THE CONSIDERATION TO BE GIVEN BY EACH PARTY UNDER
THIS AGREEMENT AND IN THE DECISION BY EACH PARTY TO ENTER INTO THIS AGREEMENT.

      IN WITNESS WHEREOF, the parties hereto have executed this Agreement by
persons duly authorized as of the date and year first above written.

CISCO SYSTEMS, INC.                   VISUAL NETWORKS OPERATIONS, INC.
"Cisco"                               "Licensor"

By:   /s/ Anson Chen                  By:   /s/ Steven G. Hindman
   --------------------------            -----------------------------

Name:    Anson Chen                   Name:   Steven G. Hindman
     ------------------------              ---------------------------

Title:   VP/GM NMSTG                  Title:  Executive Vice President
      -----------------------               --------------------------
Date:    December 2, 2002             Date:    December 3, 2002
     ------------------------              ---------------------------

<PAGE>

                                TABLE OF EXHIBITS

 EXHIBIT A -  SOFTWARE AND ROYALTIES
 EXHIBIT B -  SOFTWARE SPECIFICATIONS
 EXHIBIT C -  PROJECT MANAGERS
 EXHIBIT D -  INTEROPERABILITY TESTING GUIDELINES
 EXHIBIT E -  END USER DOCUMENTATION
 EXHIBIT F -  TRADEMARKS AND TRADEMARK USAGE GUIDELINES
 EXHIBIT G -  LICENSOR SUPPORT
 EXHIBIT H -  ESCROW AGREEMENT
 EXHIBIT I -  END USER LICENSE
 EXHIBIT J -  NON-DISCLOSURE AGREEMENT

                                                                   Page 11 of 47
<PAGE>

                                    EXHIBIT A

                             SOFTWARE AND ROYALTIES

      1. Payment. For each Software copy reproduced and distributed for revenue
by or under the sublicense rights of Cisco, Cisco shall pay a per copy royalty
of [***] of Net Invoice Price received by Cisco from the distribution of the
Software. In the event Software is sold on a stand-alone basis, "Net Invoice
Price" shall mean the Cisco's actual revenue received from the distribution of
the Software hereunder, less deductions for refunds, returns, taxes, export fees
and duties.

In the event Software is bundled with other Cisco products, "Net Invoice Price"
shall mean the amount equal to Licensor's Proportionate Share (as determined
below) of Cisco's actual revenue received from the distribution of the Software
hereunder, less deductions for refunds, returns, taxes, export fees and duties.
"Licensor's Proportionate Share" shall be determined by dividing the reference
price of the Software by the sum of the list prices of the bundle components.

[***]

      2. Payment Terms. All undisputed royalties will be paid quarterly,
pursuant to Cisco's fiscal year. Cisco will provide Licensor within forty-five
(45) days after the end of a Cisco fiscal quarter, (a) a report, substantially
in the form as follows, showing the total invoices sent to Cisco's customers in
the previous quarter and the Net Revenue received therefrom; and (b) a payment
equal to royalties owed to Licensor related thereto (or, if the credits owed to
Cisco hereunder exceed the amount of royalties owed in a particular quarter, an
invoice, payable by Visual within thirty (30) days of receipt, for the amount of
the excess). Cisco shall be entitled to credit for returns of the Software
within [***] days from the date Cisco ships the Software. Any such credit will
be offset against or deducted from royalties or other fees due to Licensor
hereunder. In the event a customer makes a return for which Cisco does not
receive a credit, Cisco shall be entitled to a credit against a future purchase
by the same customer of the returned Software (or a subsequent version of such
Software). To the extent that any royalties are in dispute, the parties agree to
reasonably cooperate to resolve such dispute as quickly as reasonably possible.

Licensor retains complete discretion to change its software product price list
or to discount the list price of its products. Notwithstanding any changes in
Licensor's software product price list, the prices set forth in the Reference
Price List shall not increase during the term of this Agreement. Licensor shall
provide Cisco with written notice of a modification to its software product
price list ninety (90) days before the effective date of any such modification
unless the parties agree in writing to a shorter notice period. If Licensor's
list price on its software products is reduced, Licensor will extend the price
reduction to Cisco as of the date of written notice of such price reduction.

CISCO SYSTEMS
FY -YEAR-
-QUARTER-

-----------------------------------------------------------
Software          Units Shipped      Net       Royalty
                                     Invoice
                                     Price
-----------------------------------------------------------
Xxxxx
-----------------------------------------------------------

-----------------------------------------------------------
Yyyyy
-----------------------------------------------------------
TOTALS:
-----------------------------------------------------------

                                                          ------------
                                     TOTAL ACCRUAL:       $0.0
                                                          ------------

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 12 of 47
<PAGE>

      3. Audit Rights. Cisco shall maintain, for a period of [***] years after
the end of the year to which they pertain, complete records of the Software
manufactured and/or distributed by Cisco in order to calculate and confirm
Cisco's royalty obligations hereunder. Upon reasonable prior notice, Licensor
will have the right, exercisable not more than once every [***] to appoint an
independent accounting firm or other agent reasonably acceptable to Cisco, at
Licensor's expense, to examine such financial books, records and accounts during
Cisco's normal business hours to verify the royalties due from Cisco to Licensor
herein, subject to execution of Cisco's standard confidentiality agreement by
the accounting firm or agent; provided, however, that execution of such
agreement will not preclude such firm from reporting its results to Licensor. In
the event an audit discloses an underpayment or overpayment of royalties due
hereunder, the appropriate party will promptly remit the amounts due to the
other party. If any such audit discloses a shortfall in payment to Licensor of
more than five percent (5%) for any quarter, Cisco agrees to pay or reimburse
Licensor for the expenses of such audit.

      4. [***]

      5. Support Compensation. Licensor shall be compensated for and shall
perform Level 1 through Level 3 support, as follows:

(a) Initial Support Agreements: Cisco shall pay Licensor [***] of the net
revenue received by Cisco of the portion of each initial Single-Year SAS Support
Agreement, initial Multi-Year SAS Support Agreement and Master SAS Support
Agreement sold covering support for the Software attributable to support of the
Software. [***]

(b) Support Agreement Renewals: Cisco shall be responsible for generating all
renewal sales and shall pay Licensor [***] of net revenue for each Support
Agreement Renewal, provided that Licensor submits a report to Cisco within
forty-five (45) days after each Cisco fiscal quarter end, detailing a list of
Customers and Cisco support contracts expiring in the following quarter. Such
report shall list the Customer name, Support Agreement number, term of support,
effective date of support, the Software identification numbers being renewed,
and the total list price. Cisco shall thereafter submit a quarterly renewal
report to Licensor in accordance with subparagraph (e) below. Licensor's
obligation to submit support renewal reports to Cisco is contingent upon Cisco
providing report information identified in subparagraph (f) below to Licensor
for Licensor to complete support renewal reports for otherwise new support
contracts. Licensor's obligations to submit renewal reports shall cease when
Cisco has implemented an automated ability to track Support Agreement renewals
and has provided Licensor thirty (30) days' advance written notice of such
automation.

(c) [***]

(d) Shared Support: Although Cisco will endeavor to discourage Support Agreement
sales and Renewals to Customers by a Cisco service integrator through Cisco's
SIS'98 or other shared support programs ("Shared Support") when such sale or
renewals are identified and accepted, the same percentage compensation noted in
subparagraph (b) above shall be paid to Licensor.

(e) [***]

(f) Quarterly Report: For Initial Support Agreements and Renewals, Cisco shall
submit (a) a report to Licensor within forty-five (45) days after each Cisco
fiscal quarter end, detailing each Customer invoiced for support during such
quarter, the Customer name, Support Agreement number, term of support, effective
date of support Software identification numbers, and the total list price; and
(b) a payment equal to support fees owed to Licensor by Cisco in accordance with
this Section 5. Licensor shall identify and advise Cisco of any issues
pertaining to the quarterly reports within fifteen (15) business days after
receipt of Cisco's report. If no issues are raised with such timeframe, the
report shall be deemed accepted by Licensor. Cisco and Licensor will work in
good faith to resolve any issues within a further thirty-day period.

(g) Non-Payment: In the event that Cisco is not in receipt of the invoiced
support fees due from a Customer, Cisco may terminate the support of that
individual Customer, less a pro-rata amount for the Licensor's agreed support
compensation commencing on the date support started through the date that Cisco
notifies Licensor that it has

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 13 of 47
<PAGE>

terminated support

(h) Credits: Section 3 of this Exhibit A to the Agreement regarding credit for
returns or offsets against License fees due to Licensor also will apply with
regard to maintenance and support fees. In addition, If a Cisco customer cancels
or terminates its annual maintenance agreement with Cisco for which it has paid
maintenance fees in advance and Cisco provides a pro-rata credit or refund to
the customer of the unused portion of the maintenance fees paid, Licensor will
provide Cisco with a credit or refund in the amount of the unused portion of the
maintenance fees paid to Licensor. On a quarterly basis, Cisco will notify
Licensor of such refund or credit.

(i) Payment Schedule: Cisco shall pay Licensor the compensation reflected in
subsection (a), (b), and (e) above, as applicable, for the term of such Support
Agreement or Support Agreement Renewal together with any additional percentage
based upon customer satisfaction bonus goals outlined in Exhibit G and any
additional fees for Shared Support, within forty-five (45) days after Cisco's
fiscal quarter end. Any supplement payment or credit shall be paid to Licensor
during the immediate subsequent quarter; whereby Cisco shall make one payment
during its fiscal quarter to Licensor for all then-current applicable
compensation. Any credit or refund due Cisco shall be issued or paid by Licensor
within forty-five (45) days following the Cisco fiscal quarter in which Cisco
provides notice of such credit or refund to Licensor.

(i) Change in Compensation: At any time after the first twelve (12) months from
the effective date of Exhibit F, upon thirty (30) days' written notice to
Licensor, Cisco may, at its election, request additional Software training above
from Licensor so that Cisco may assume additional support obligations after such
training. Such additional training shall be offered to Cisco at a [***] discount
off Licensor's standard pricing for support training. If Cisco assumes
additional support responsibilities, compensation to Licensor shall be
negotiated in good faith at a lower compensation percentage.

k) [***]

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 14 of 47
<PAGE>

                                   SCHEDULE 1
[***]

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 15 of 47
<PAGE>

                                    EXHIBIT B

                             SOFTWARE SPECIFICATIONS

1. Software to be Licensed to Cisco - (a) Visual UpTime Performance Archive
                                          Managers (PAMs); and
                                      (b) license keys which enable PAMs to
                                          manage Cisco products with Visual
                                          UpTime functionality.

2. Cisco Property - None

                                                                   Page 16 of 47
<PAGE>

                                    EXHIBIT C

                                PROJECT MANAGERS

For Cisco:

Program Manager
Jayesh Ghia
408 525-8675
jghia@cisco.com

Testing Project Manager
Kui Zhang
(408) 526-7603
kzhang@cisco.com

For Visual:

              ----------------------------
              Robin Brown
              ----------------------------
              Director, Product Management
              ----------------------------
              10169 N. Blaney Avenue
              Cupertino, CA  95014
              ----------------------------
              (408) 996-2002
              ----------------------------
              rbrown@visualnetworks.com
              ----------------------------

                                                                   Page 17 of 47
<PAGE>

                                    EXHIBIT D

               INTEROPERABILITY AND ACCEPTANCE TESTING GUIDELINES

This Exhibit D specifies, or describes the process for specifying,
interoperability, unit, and acceptance test criteria for tests, measures, and
forms of test result reports required to test the ongoing interoperability of
the Visual Networks products that will interact and integrate with Cisco's
products under this Agreement.

1.    Confidentiality. All test data, procedures and results will be treated as
      Confidential Information subject to the Confidential Information section
      in this Agreement.

2.    Continued Operability and Improvement. The product components, including
      but not limited to, IE2100, Visual Uptime, CNS Event Gateway, IOS Service
      Assurance Agent (hereinafter referred to as "SAA") shall continue to
      function as stated in their respective documentation sets, with necessary
      deviations defined in the Technical Specifications. Any new releases of
      the Software shall represent an increase in functionality, performance,
      and usability, above and beyond the current available Visual Uptime, CNS
      Event Gateway and IOS SAA individual products.

3.    Joint Testing. Visual Networks and Cisco will jointly test their products
      to determine compatibility, utilizing the test criteria herein. The
      results will be shared between the two companies. Each company will own
      their respective results.

4.    Scope of Testing and Results. The features and functions shall be tested
      by Visual Networks, at unit, development, interoperability with Cisco
      products, scalability, performance and system testing levels, pursuant to
      testing criteria jointly developed by the parties and defined in the
      Engineering Test Plan. Visual Networks shall be able to demonstrate to
      Cisco how features and functions are tested, accompanied by design
      documentation, test procedures, and test results.

5.    Final Look-and-Feel. The final acceptance of eventual Cisco look-and-feel,
      icons, integration, documentation, etc. shall be done by Cisco
      engineering, technical publications and marketing personnel as designated
      by the Cisco project manager and in accordance with the Product
      Requirements Document and for WAPMS and Exhibit E of this Agreement. This
      acceptance will not be unreasonably withheld.

6.    Unit and Development Testing. The Software, in object code form, will be
      unit tested using simulators, code debugging tools, and lab equipment, as
      appropriate and described in the testing criteria develop under Section 4
      of this Exhibit D (lab equipment is comprised of routers and necessary
      cards provided by Cisco solely for the purposes of developing and testing
      the Software). This testing will be the responsibility of the Visual
      Networks development team. The deliverable will be defined as: unit tested
      code ready for Validation Testing.

      6.1.  Deliverables. Validation Tested Code ready for Acceptance Testing
            (the software deliverable will include an installable image, User
            Guide Final Content, Support Plan Final, Installation Manual Final
            Content) and a Unit Test Results Document including but not limited
            to: test criteria, description of test methodology, results

7.    Interoperability and General Testing. Visual Uptime shall interoperate
      with the CNS Event Gateway, IOS devices, and all necessary software and
      hardware components comprising the WAPMS product/solution. Cisco shall
      make appropriate hardware and software available to Visual Networks in
      order that Visual Networks may perform required scalability and system
      testing. For the avoidance of doubt, it is understood that Cisco may
      choose to make such hardware and software available in its labs or
      otherwise on its premises. Interoperability testing shall be conducted by
      Visual Networks to verify operability, reliability and performance and
      test result reports shall be made available to Cisco. Cisco shall conduct
      acceptance testing based on these reports. Content of the reports and
      specific interoperability and acceptance test criteria will be jointly
      defined by the parties in the Engineering Project Plan for WAPMS.

                                                                   Page 18 of 47
<PAGE>

7.1.  Deliverables. Object Code certified to have passed interoperability and
      general testing (scalability, performance and system). Interoperability
      and general testing document including but not limited to: test criteria,
      description of test methodology, results.

8.    Acceptance Testing. Product code will be frozen and sent to Acceptance
      Testing, which will use the test plan previously documented by the parties
      pursuant to Section 4 of this Exhibit D. In the course of this testing, a
      list of bugs will be generated in Cisco's internal Defect Tracking System
      (hereinafter referred to as "DDTS") with assigned severities for
      resolution based on standard Cisco severity definitions. This task is a
      joint effort and requires the combined efforts of Cisco and Visual
      Networks test personnel and Visual Networks development team personnel.
      Throughout this effort, defect tracking will comply with Cisco's DDTS
      process and will use Cisco's DDTS system.

      8.1.  All entrance conditions must be met for Acceptance Testing, as
            specified in the Program Plan. These are: functional test cases
            executed, Validation Testing completed, all known bugs have been
            entered into DDTS, all bugs resolved as per severities listed in the
            program plan, all source code checked for memory leaks, all memory
            leaks documented in DDTS, all hardcopy documents completed.

      8.2.  Deliverables. System Tested software, Clearcase entries completed,
            all hardcopy documents completed.

      8.3.  The Cisco testing project manager will assess the conformance of the
            Software to the Engineering Test Plan and provide either a written
            acceptance or a written list of non-conformances to Visual Networks.

9.    Retesting. Visual Networks and Cisco will seek to re-test products
      whenever a significant functional change that may affect interoperability
      is made to either party's product. The parties agree that it shall be the
      responsibility of each party to inform the other party of any significant
      functional change to its product(s) which may affect interoperability with
      the other's products. A re-test of products(s) will only be conducted when
      the parties agree that it is necessary.

                                                                   Page 19 of 47
<PAGE>

                                    EXHIBIT E

                             END USER DOCUMENTATION

      1. Scope. Cisco may develop, write, manufacture and maintain all
Software-related end user documentation so that it will have a Cisco
"look-and-feel." (as defined below) and Licensor shall provide Cisco with such
documentation on media sufficient to allow Cisco to reproduce such documentation
as part of the Software pursuant to the licenses granted in this Agreement. In
addition, Licensor hereby grants Cisco the right to modify, make derivative
works of, and incorporate into Cisco product documentation the end user
documentation provided by Licensor to Cisco hereunder.

            (a) End user Software documentation content is determined by the
Software, and Cisco's documentation guidelines. Documentation will include,
without limitation, user guides, software configuration and command reference
guides, release notes and errata.

            (b) Cisco "look-and-feel" means Cisco's customer documentation
templates, style guide, and printing standards, as defined and specified from
time to time by Cisco.

            (c) Licensor agrees not to modify Cisco documentation templates.

      2. Electronic Publication. Licensor will provide an electronic copy of the
end user documentation files (including all illustrations), for the life of the
manual(s).

      3. Ownership. Cisco shall own all right, title and interest in the end
user documentation (in any format or medium) with Cisco "look and feel"
developed by or for Cisco pursuant to this Agreement (the "Cisco
Documentation"); provided, however, that Licensor retains ownership of its
pre-existing standard documentation, and the content thereof. Licensor hereby
assigns to Cisco all right, title and interest to the Cisco Documentation and
shall execute such instruments as Cisco may reasonably request to effect and
record such assignment. Licensor may not distribute the Cisco Documentation in
any format or medium or for any purpose, to any third party without the prior
written consent of Cisco.

      4. Revision Cycles. Licensor will revise the end user manual(s) as
necessary to accurately support the Software.

      (a)   Licensor will issue Software release notes or errata in a timely
            manner, and provide them to Cisco.

      (b)   Licensor will notify Cisco within thirty (30) days of Licensor's
            intent to revise a document.

      (c)   Document revisions will include all relevant Software enhancements
            and new technical information.

      (d)   With each revision, Licensor will provide electronic copies of
            files, as specified in Section 2 of this Exhibit.

                                                                   Page 20 of 47
<PAGE>

                                    EXHIBIT F

                    TRADEMARKS AND TRADEMARK USAGE GUIDLINES

                            [VISUAL NETWORKS(R) LOG0]
                     Trademark Policy and Proprietary Notice

Visual Networks Technologies, Inc. is a Visual Networks holding company, which
holds the rights to Visual Networks' intellectual property.

Our Brand Name

Our brand name is Visual Networks. The term "Visual" may not be used to refer to
Visual Networks.

Our Logo

Please see Visual Networks' Logo Usage Guidelines.

                               Proprietary Notice

IF ONLY VISUAL NETWORKS MARKS APPEAR IN THE DOCUMENT:

(C) 2002 Visual Networks Technologies, Inc. All Rights Reserved. [list Visual
Networks marks referenced in the document] are trademarks or service marks of
Visual Networks Technologies, Inc.

IF NON-VISUAL NETWORKS MARKS APPEAR IN THE DOCUMENT:

(C) 2002 Visual Networks Technologies, Inc. All Rights Reserved. [list Visual
Networks marks referenced in the document] are trademarks or service marks of
Visual Networks Technologies, Inc. Other product or service names may be
trademarks or service marks of their respective owners.

If there is a desire to specify the owner(s) of other marks, appropriate
sentences may be added. For example: [mark] is a [service mark/trademark] of
[owner name].

IF THE DOCUMENT IS NOT BEING CREATED BY VISUAL NETWORKS:

[list Visual Networks marks referenced in the document] are trademarks or
service marks of Visual Networks Technologies, Inc.

The entity creating the document would include this within their copyright and
trademark notices on the document.

For an up-to-date view of Visual Networks' proprietary notice, please visit the
Visual Networks web site at www.visualnetworks.com.

                                                                   Page 21 of 47
<PAGE>

Labeling Visual Networks Marks

Obtaining and protecting legal trademarks and service marks is something that
must be taken seriously. Adjustments such as changing spacing, changing which
letters are capitalized, or incorrectly using (R) when you intend to use (TM),
or vice versa, can seem like minor details, but can lead to serious legal
consequences.

It is common, and legally acceptable, to label a trademark or service mark with
the (R) or (TM) symbol only once, at its initial usage in the body of a text
document (as opposed to a title line or heading). It is not necessary to use the
(R) or (TM) labels after the first occurrence of a trademark or service mark in
a prose document.

Questions? Contact Jeff Norton, Corporate Counsel, at 301.296.2742,
jnorton@visualnetworks.com.

                                                                   Page 22 of 47
<PAGE>

                                    EXHIBIT G
                                LICENSOR SUPPORT
                                   (Software)

This Exhibit F pertains to support for Licensor's Software.

Definitions: The following terms shall have the meaning assigned to them.
Capitalized terms not defined herein shall have the meaning assigned to them in
the Agreement.

"Agreement" means that OEM Software License Agreement by and between Licensor
and Cisco, effective December 3, 2002.

"Customer" means Cisco's end-user of the Software who is requesting support.

"INSMBU" means Cisco's Intelligent Network Services Management Business Unit.

"Error" means a bug in the Software.

"Maintenance Release" means an incremental release of Software that provides
maintenance fixes and may provide additional Software features. Maintenance
releases are designated by Cisco as a change in the digit(s) to the right of the
tenths digit of the Software version number [x.x.(x)].

"Major Release" means a release of Software that provides additional Software
features and/or functions. Major Releases are designated by Cisco as a change in
the ones digit of the Software version number [(x).x.x].

"Minor Release" means an incremental release of Software that provides
maintenance fixes and additional Software features. Minor releases are
designated by Cisco as a change in the tenths digit(s) of the Software version
number [x.(x).x].

"Multi-Year Support Agreement" means a Support Agreement having a term greater
than one (1) year.

"SAS" means Cisco's current standard software application service offering which
includes Software bug fixes and patches and maintenance Updates (Minor
Releases). .

"Single-Year Support Agreement" means a Customer Support Agreement having a term
of at least one (1) year, but less than two (2) years.

"Support Agreement" means a support contract between Cisco and a Customer for
the provision by Cisco of support and maintenance for the Software and shall
include contracts for the initial period of support, renewal of such support,
and reinstatement of expired support.

"Support Agreement Renewals" means Software maintenance, which is purchased by a
Customer at least twelve (12) months after the initial Support Agreement.

"Updates" means Maintenance Releases, Version Releases, and/or Major Releases
which contain the same configuration as originally acquired.

"Version Release" means an incremental release of Cisco Software that provides
maintenance fixes and additional Software features. Version releases are
designated by Cisco as a change in the tenths digit(s) of the Software version
number [x.(x).x].

1. SUPPORT LEVEL DEFINITIONS

1.1 Level 0 Support. Level 0 Support means that Customer shall have access to
Cisco's Global Call Center and shall have access to Cisco's Technical Assistance
Center for verifying Software support entitlement. Level 0

                                 Page 23 of 47
<PAGE>

Support shall be provided directly to Customer customers by Cisco.

1.2 Level 1 Support. Level 1 Support includes the ability to provide general
Software information and configuration support; collect relevant technical
problem identification information; perform base problem determination; provide
basic support on the standard protocols and features. Level 1 Support shall be
provided directly to Customers by Licensor.

1.3 Level 2 Support. Level 2 Support includes Level 1 Support plus the ability
to support problem isolation and Software specification defect determination;
provide lab simulation and interoperability testing; define an action plan;
analyze traces; provide advanced support on all protocols and features; filter
non-technical problems from technical problems, reproduce problems in a lab, and
diagnose problems remotely. Level 2 Support shall be provided directly to
Customers by Licensor.

1.4 Level 3 Support. Level 3 Support includes fixing or generating workarounds
for Software bugs and troubleshooting bugs that were not resolved during Second
Level Support. Level 3 Support shall be provided directly to Customers by
Licensor.

2. PROBLEM PRIORITIES DEFINITIONS

Problem priorities shall be classified as follows:

2.1 Priority 1: Cisco's customer is experiencing problems with the Software,
which is causing critical impact to business operations if service is not
restored quickly. No work-around is available. If a work-around is available,
the priority may be reduced to either a Priority 2, Priority 3 or Priority 4, as
identified below. Cisco, Cisco's customer, and Licensor will commit full-time
resources around the clock to resolve the situation.

2.2 Priority 2: Cisco's customer is experiencing problems with the Software,
which is impacting significant aspects of business operations. No work-around is
available. If a work-around is available, the priority may be reduced to either
a Priority 3 or Priority 4, as identified below. Cisco, Cisco's customer, and
Licensor will commit full-time resources during Business Hours to resolve the
situation.

2.3 Priority 3: Cisco's customer's network performance is degraded. Network
functionality is noticeably impaired, but most business operations continue.

2.4 Priority 4: Cisco or Cisco's customer requires information or assistance on
Software capabilities, installation, or configuration.

2.5 "Business Hours" means 6:00 a.m. to 6:00 p.m., Pacific Standard Time, Monday
through Friday, excluding Cisco-observed holidays.

3. ESCALATION GUIDELINES

3.1 The following table sets forth the escalation guidelines by which Licensor
shall address customer support problems reported by Cisco and involve its
management personnel to address such problems. Priority 1 problem escalation
times are measured in calendar hours, twenty-four (24) hours per day, seven (7)
days per week. Priority 2, Priority 3, and Priority 4 escalation times
correspond with Business Hours. The Licensor manager to whom the problem is
escalated will take ownership of the problem and ensure that updates are
provided to the appropriate Cisco personnel. Cisco-initiated escalation's will
begin at the Technical Support Group Leader level and proceed upward. This will
allow those most closely associated with the support resources to correct any
service problems quickly.

3.2 It is Cisco's policy to work with its customer to establish the Priority for
a problem and to accept the customer's determination of the Priority. Licensor
shall accept the Priority designation agreed to by Cisco and

                                 Page 24 of 47
<PAGE>

Customers and communicated to Licensor by Cisco. Licensor will work with Cisco
according to the processes and procedures contained in this Exhibit F.

-------------------------------------------------------------------------
Elapsed Time  Priority 1       Priority 2     Priority 3     Priority 4

-------------------------------------------------------------------------
              Technical
1-Hour        Support
              Group Leader

-------------------------------------------------------------------------
              Technical        Technical
4-Hour        Support          Support
              Director         Group Leader
-------------------------------------------------------------------------
              Vice President   Technical
24-Hour       Engineering      Support
                               Director
-------------------------------------------------------------------------
48-Hour       President (CEO)  Vice
                               President
                               Engineering
-------------------------------------------------------------------------
72-Hour                                       Technical
                                              Support
                                              Group Leader
-------------------------------------------------------------------------
96-Hour                        President      Technical      Technical
                               (CEO)          Support        Support
                                              Director       Group
                                                             Leader
-------------------------------------------------------------------------

        1.    Name: Linda Vargas
              Title: Tech Support Lead
              Phone: (301) 296-2738
              Pager or Cell: (301) 529-9037
              Email: lvargas@visualnetworks.com

        2.    Name: Jeff Rotruck
              Title: Director, Customer Service
              Phone:   (301) 296-2328
              Pager or Cell:  (240) 401-4406
              Email: jrotruck@visualnetworks.com

        3.    Name: Wayne Fuller
              Title: EVP, Product Operations
              Phone: (301) 296-2673
              Pager or Cell:  (703) 629-3427
              Email: wfuller@visualnetworks.com

        4.    Name: Peter Minihane
              Title: President & CEO
              Phone: (301) 296-2365
              Pager or Cell: (240) 401-4863
              Email: pminihane.visualnetworks.com

4. SUPPORT

4.1 Software Support. Licensor will support any release of Software for the
longer of: (a) the time until the general availability of the release that is
two releases after such release; and (b) twenty-four (24) months, meaning that
for that time period, Errors in that release will be corrected either by means
of a patch or correction to that release. For a period of twelve (12) months
after the initial Software Support term for a release referenced above, Software
Support shall be offered to Cisco, if requested by Cisco, at Licensor's
reasonable and customary time and materials

                                                                   Page 25 of 47
<PAGE>

rates. Subject to the prior written approval of the Cisco Serviceability Design
Engineer for the Software, which approval shall not be unreasonably withheld, a
subsequent release may be substituted to correct an Error in any Software
release. Software releases shall be downward compatible, so that new releases
are compatible with pre-existing configurations and data formats. Whenever
commercially reasonable, Licensor shall have the capability to electronically
transfer Software updates, upgrades, and patches/fixes to Cisco.

4.2 Customer Support. Cisco will provide Level 0 Support in the same manner that
it provides such support for its other similar Software. Licensor will provide
Level 1 Support, Level 2 Support, and Level 3 Support to a Customer by telephone
and/or e-mail seven (7) days a week, twenty-four (24) hours per day, with a
maximum one (1) hour telephone response time for all Priority 1 and Priority 2
problems. In the event that diagnostics and troubleshooting are required at a
Customer site, as reasonably determined by Cisco, Cisco and Licensor will
provide, at their own expense, the necessary resources for problem resolution in
accordance with each party's respective obligations hereunder. Each party shall
be entitled to recover its actual and reasonable expenses from the other party
or from the Customer if it is later determined that the cause of the problem is
so attributable. Cisco shall provide Licensor feedback on any Software bugs and
potential fixes. Licensor shall use commercially reasonable efforts to resolve
Software bugs.

4.3 Initial Call Flow Process

(a) Customer contacts Cisco's Global Call Center ("GCC") via Cisco's "800"
number or the Customer opens their own case on-line via Cisco Case Open Tool.
The GCC shall perform Level 0 Support by verifying customer support entitlement
and opening a case in Cisco's CARE database ("Clarify"). The case is then
dispatched to the INSMBU-VISUAL NETWORKS CARE queue, which shall generate an
internal case at nfm-Licensor-support@cisco.com, which shall be forwarded to
Licensor's support email alias as provided to Cisco by Licensor Technical
Support Group ("TSG"). INSMBU shall send a page for all P1 and P2 cases to the
appropriate Licensor technical support pager and make reasonable efforts to send
an email message and a message to support@visualnetworks.com and a message via
phone to (800) 708-4784. In that respect, Licensor TSG shall provide its
technical support schedule to Cisco and update such schedule if there are any
changes via email. Licensor TSG shall report the time that it contacted the
Customer, which is based on the support priority reflected in Section 4.4 below,
and the associated Licensor case number to INSMBU within twenty-four hours after
initial case response. Licensor TSG shall provide INSMBU with case updates on a
weekly basis or more often if reasonably requested by Cisco. In turn, INSMBU
will update cases in CARE on a weekly basis. While Licensor TSG is working on
the case, INSMBU will update the case in CARE stating "This case is currently
being supported by our third-party Licensor. The LICENSOR case reference is:
XXXX. If you have any questions, please call 1-800-LICENSOR_TSG." Licensor TSG
will notify INSMBU when the case is ready to be closed. INSMBU will close the
case when resolved, with case details. A customer satisfaction survey, as
reflected in Section 9 hereinbelow, will be sent via CARE to the Customer after
the case is closed.

(b) A troubleshooting tips document for the Software, prepared and maintained by
Licensor TSG, will be made available to Cisco for Customer's on-line use in
troubleshooting the problem, without Cisco's or Licensor's assistance. If the
problem is not resolved, the case will be escalated to Licensor's TSG to perform
Level 1, Level 2, and Level 3 Support, as appropriate. Licensor TSG may consult
with INSMBU if necessary, but will work directly with the Customer to resolve a
Software problem. INSMBU may occasionally call Licensor's TSG directly for case
status.

(c) When Cisco's Customer Support database is modified by Cisco to allow
appropriate supplier access, Licensor and Cisco will work in good faith to
develop a call flow transition plan so that all case information is updated and
transferred to the Cisco database.

4.4 Support Prioritization and Escalation Guidelines. To ensure that all
Software problems and technical inquiries are reported in a standard format,
Licensor will use and comply with the problem priority definitions and
escalation guidelines herein pursuant to Section 3.2. Based on the priority of a
Software problem, Licensor will provide to Cisco fixes or work-arounds in the
following time frames:

                                                                   Page 26 of 47
<PAGE>

o     Priority 1: Fix or work-around within eight (8) hours of problem report to
      Licensor;

o     Priority 2: Fix or work-around within two (2) business days of problem
      report to Licensor;

o     Priority 3: Fix or work-around within two (2) weeks of problem report to
      Licensor;

o     Priority 4: Fix or work-around within one (1) month of problem report to
      Licensor.

For Priority 3 or Priority 4 problems, if Licensor is unable to meet the time
frames listed above, the Licensor will provide to Cisco within that time frame,
at a minimum, a plan for addressing the problem.

4.5 Support Documentation. Promptly upon Cisco's written request, Licensor will
supply Cisco with all technical documentation and resources that Cisco
reasonably determines to be useful or necessary to perform Customer support or
to analyze the technical benefits and risks of introducing new releases of
Software into the Customer base. Such support documentation will include,
without limitation: (i) Software specifications, (ii) release notes, (iii)
debugging/support tools, and (iv) where available, lists of all error messages
with explanations as needed and recommended actions. Licensor will regularly
supply Cisco with all release notes or other documentation defining the relevant
Software information, symptoms, solutions or work-arounds for Software problems.
Licensor will keep accurate records of Software bugs and make such reports
available to Cisco at least quarterly. Licensor will maintain an electronic
means (e.g., an FTP server) through which Cisco can obtain up-to-date
information on Software bugs, fixes, and code updates. During the term of this
Agreement, Licensor will provide such support to Cisco at no charge.

5. Training.

5.1 Upon Cisco's request, Licensor shall offer, at no cost to Cisco, prior to
Licensor's first commercial shipment of any major Software release and at least
annually thereafter, general Software training in the service and maintenance of
Licensor's Software as mutually agreed by the parties, so that Cisco can perform
its then-current support obligations hereunder. Cisco shall be responsible for
all travel expenses, which Cisco may incur in connection with such training.
Upon Licensor's request and as mutually agreed by the parties Cisco shall offer,
at no cost to Licensor technical training on its software which is associated
with Licensor's Software so that Licensor can perform its then-current support
obligations hereunder. Licensor shall be responsible for all travel expenses,
which Licensor may incur in connection with such training. The parties shall use
commercially reasonable efforts to schedule such training concurrently to
minimize travel costs.

5.2 Upon Cisco's request, more detailed Software training shall be offered to
Cisco at such time and place as reasonably and mutually agreed, which shall
include, if necessary, compatibility issues and engineering debug capabilities.
All of Licensor's reasonable expenses in connection with such additional
training shall be pre-approved and reimbursed by Cisco, consistent with Cisco's
standard policies. Such additional training shall be offered to Cisco at a [***]
discount off Licensor's standard pricing for support training. Cisco shall be
responsible for all travel expenses, which Cisco may incur in connection with
such training.

6. Global Business Reviews. Unless otherwise mutually agreed, business reviews
will be held remotely on a quarterly basis, after the close of Cisco's fiscal
quarter, to assess Licensor's performance against the support objectives.
Reviews will include the resetting of support standards for subsequent periods,
establishing and measuring the performance record of Licensor, reviewing levels
of call escalations and resolutions, providing general business updates,
identifying any process improvement opportunities, reviewing forecasts of
anticipated demand for the next one-hundred and eighty (180) day period,
reviewing any quality assurance issues, reviewing any customer satisfaction
issues, and addressing any other issues raised with reasonable advance notice by
either party. Each party will provide any information, which is reasonably
requested by the other party and will work with the other party to resolve any
issues, concerns or problems identified within a reasonable amount of time. The
location and/or meeting method will be mutually agreed upon by the parties and
will be attended by the respective parties' Account Representative and by such
other personnel as are appropriate.

7. Support Level Requirements:

7.1 Licensor shall:

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 27 of 47
<PAGE>

(a) Provide all the labor, expertise, and skills necessary for the performance
of the support services in a manner reasonably satisfactory to Cisco and Cisco's
customers. Licensor shall provide a Technical Tips Sheet for Customer's access
on-line, describing the top ten support problems and solutions and use Cisco's
phone support script as provided to Licensor by Cisco . The Technical Tips Sheet
shall be available to Cisco electronically and shall be updated by Licensor TSG
from time to time.

(b) [***]

(c) Identify bugs in other Cisco Software, which is associated with the Software
as well as the Software and communicate those bugs to Cisco's DE on a weekly
basis.

(d) Employ competent technical support and maintenance organizations, and use
professional standards in the industry while performing services to Cisco and
Customers hereunder.

(e) Provide Software patches and bug fixes to Cisco electronically so that
Customers can access such updates and upgrades from Cisco's software upgrade
tool.

(f) Upon Cisco's request, keep Cisco advised on the progress of the Customer
support cases and the status of the support services.

(g) Keep accurate records of support services performed, evidence of which
Licensor shall provide to Cisco upon resolution of each customer case.

(h) Upon reasonable advance notice, permit any designated representative of
Cisco to periodically review during normal business hours Licensor's support
center and observe the personnel who are performing support services for Cisco.

(i) Establish a problem reporting and tracking mechanism of support services
performed by Licensor, which is reasonably acceptable to Cisco.

(j) Keep Cisco informed as to any problems, which involve the Software and/or
Cisco technologies or impact Licensor's ability to deliver service or solutions
to Cisco's customer, to communicate such problems promptly to Cisco, and to
assist Cisco in the resolution of such problems.

(k) Appoint a relationship manager whose primary responsibility will be to work
with the designated Cisco Serviceability Design Engineer or Cisco DE to manage
the implementation of the support model, act as the focal point for day-to-day
support issues and problem escalations, and participate in Cisco support-related
activities.

Licensor shall not:

(a) Subcontract its duties and responsibilities hereunder to any other person or
entity, in whole or in part, without prior written notice to and approval by
Cisco, which consent shall not be unreasonably withheld.

(b) Disclose any Cisco customer support information to third parties without
Cisco's prior written consent.

(c) Assign this support exhibit or any rights hereunder, without Cisco's prior
written consent.

8. Customer Satisfaction

8.1 Customer Satisfaction Survey: Cisco will survey its Customers under Software
Support for the purpose of ensuring customer satisfaction with the Software and
Licensor's support. For such purposes, Licensor shall provide Cisco with any
necessary customer contact information to conduct such a survey. Cisco shall
accumulate a monthly average of the customer satisfaction scores from these
surveys (sample attached).

8.2 Customer Satisfaction Scores: Customer satisfaction survey scores are
defined as follows:

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 28 of 47
<PAGE>

"Delighted Score" means that all survey questions had a response of 5.

"Dissatisfied Score" means that one or more survey questions had a response of 1
or 2.

"Satisfied Score" encompasses everything else, i.e. no 1's and 2's, but not all
5's.

8.3 Customer Satisfaction Goals and Bonus: Licensor's customer satisfaction
goal, at a minimum, shall be to achieve a Satisfied Score. (c) During each Cisco
fiscal quarter from the effective date of this Exhibit F and continuing through
subsequent quarters thereafter, in the event that the customer satisfaction
surveys average at least [***] during any Cisco fiscal quarter, Licensor shall
receive a customer satisfaction bonus of [***] of the list price from the sale
of an Initial Support Agreement or Support Agreement Renewal.

8.4 Dissatified Score: In the event any customer satisfaction surveys contains a
Dissatisfied Score in any Cisco fiscal quarter, Licensor shall promptly contact
the Customer who submitted the Dissatisfied Score to gather input about such
score and provide Cisco with a case report which contains the details for such
score and Licensor's corrective action. At any time, if [***] or more of the
customer satisfaction surveys contain a Dissatisfied Score in any Cisco fiscal
quarter, Cisco shall notify Licensor and Licensor shall comply with
subparagraphs (a) and (b) below:

(a) Licensor will have five (5) business days from the date that Cisco gives
Licensor a written notice of non-compliance to develop and present to Cisco a
corrective action plan that will enable Licensor to meet the applicable customer
satisfaction goals.

(b) Licensor will have thirty (30) days from the date that Cisco gives Licensor
a written notice of non-compliance to initiate the corrective action plan to
meet the applicable customer satisfaction goals.

8.5 Termination for Dissatisfaction Score: In the event that [***] or more of
the customer satisfaction surveys contain a Dissatisfaction Score for two (2)
consecutive Cisco fiscal quarters, at Cisco's option Cisco may (i) immediately
terminate Licensor's support services, and (ii) invoke transition training, as
reflected in Section 12 below. Cisco shall be invoiced for reasonable fees for
services actually rendered by Licensor prior to termination.

9. CISCO AND LICENSOR CONTACTS:

Cisco Contact Information

      1. For questions concerning this Exhibit:

      Name:  Scott Mousley, Serviceability Design Engineer
             (Office) phone number:  408 525-5945
             (Pager) phone number:  800-365-4578
      Email:  smousley@cisco.com

      2. For questions concerning Software Support:

      Name:  Kui Zhang, Mgr. Software Development
             (Office) phone number: 408 526-7603
             Email:  kzhang@cisco.com

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 29 of 47
<PAGE>

3. For questions concerning Entitlement:

               Name: Rebecca Sanders,
               Mgr. Joint Venture Engineering Group - INSMBU
               (Office) phone number: 408 853 9754
               Cell: 512 917-8720 Pager: (800) 365-4578
               Email: resande@cisco.com

               Name: Andrew Zielinski, Product  Mgr. - INSMBU
               (Office) phone number: 408 527 4831
               Pager: 408 322-9842
               Email: azielins@cisco.com

4. For legal notices under this Exhibit:

               Cisco Systems, Inc.
               170 West Tasman Drive
               San Jose, CA  95134
               Attn: VP Legal Services and General Counsel
               Fax: (408) 526-7019
               Phone: (408) 526-4000

Licensor Contact Information

       1. For questions concerning Software Support:

               Name: Linda Vargas
               Title: Tech Support Lead
               Phone: (301) 296-2738
               Pager or Cell: (301) 529-9037
               Email: lvargas@visualnetworks.com

       2. For questions concerning this Exhibit:

               Name: Wayne Fuller
               Title: VP, Engineering
               Phone: (301) 296-2673
               Pager or Cell:  (703) 629-3427
               Email: wfuller@visualnetworks.com

      3. For legal notices under this Exhibit:

               Visual Networks Operations, Inc.
               Attn: Corporate Counsel
               2092 Gaither Road
               Rockville, MD 20850
               301.296.2731 - fax
               301.296.2742 - voice

                                                                   Page 30 of 47
<PAGE>

10. Support Compensation: In exhange for Licensor's support as reflected in this
Exhibit, Cisco shall compensate Licensor pursuant to the terms of Section 5 of
Exhibit A of the License Agreement.

11. SUPPORT TERM AND TERMINATION.

11.1 This support exhibit shall be co-terminous with the Agreement. In that
respect, in addition to this Section, Sections 13.1, 13.3, and 13. 4 of the
Agreement shall apply to this support exhibit.

11.2 Cisco may terminate this support exhibit at any time for its convenience,
for no reason or for any reason, with sixty (60) days' written notice to
Licensor. In the event of such termination, Cisco shall be entitled to a
prorated portion of any unused fees paid for support.

11.3 Transition Training: Upon termination or expiration of Licensor's support
services herein, if requested by Cisco, Licensor shall provide technical
training to Cisco at such time and place as is reasonably requested by Cisco and
shall include, but not be limited to, conventional engineering training and
instruction classes in the service and maintenance of the Software as well as
instruction on resolving compatibility issues and engineering debug
capabilities. Such transition training shall continue until Cisco can
efficiently perform Level 1 and Level 2 support for the Software. All of
Licensor's reasonable expenses in connection with such transition training shall
be pre-approved and reimbursed by Cisco, consistent with Cisco's standard
policies. Such additional training shall be offered to Cisco at a [***] discount
off Licensor's standard pricing for support training.

          11.4 In the event of any termination or expiration of the Agreement,
          at Cisco's request, Licensor shall make available to Cisco Level 3
          support reflected in this Exhibit F, or other agreed support, at
          Licensor's reasonable and customary rates for a minimum of two (2)
          years after such termination or expiration.

          11.5 The terms and conditions of this Section 11 supersede any terms
          and conditions of the Agreement, which are inconsistent with these
          terms and conditions.

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 31 of 47
<PAGE>
Customer Satisfaction Survey

Subject: Cisco Systems Survey

Recently you contacted the Cisco _To be filled in____.

We appreciate the opportunity to assist you, and we hope we were responsive to
your needs.

CASE: CR-XXXXX OPENED: 00-XX-XXXX         AGENT:

DESCRIPTION:

On a scale of 1 to 5 (1= Unacceptable, 2 = Poor, 3 = Met your needs, 4 - Good, 5
= Excellent) rate each of the following

(PLACE YOUR ANSWERS IN THE SURVEY AFTER EACH COLON).

<TABLE>
<S>                                                                    <C>
(Q1) Ease of Access to Help line....................................  (1-5): COMMENTS ON Q1:

(Q2) Timeliness of Information......................................  (1-5): COMMENTS ON Q2:

(Q3) Effectiveness of Information...................................  (1-5): COMMENTS ON Q3:

(Q4) Software Knowledge of the Agent................................  (1-5): COMMENTS ON Q4:

(Q5) Courteous Service..............................................  (1-5): COMMENTS ON Q5:

(Q6) OVERALL satisfaction of customer regarding software support ...  (1-5): COMMENTS ON Q6:
</TABLE>

What could we do to better support you?

---------------------------
Thank you for letting us know how we're doing and giving us the opportunity to
improve.

Sincerely,

                                                                   Page 32 of 47
<PAGE>

                                    EXHIBIT H

                                ESCROW AGREEMENT

      This Escrow Agreement ("Escrow Agreement"), is entered into as of
________________ (the "Effective Date"), by and among Cisco Systems, Inc., a
California corporation, with offices at 170 W. Tasman Drive, San Jose, CA 95134
("Cisco"), Visual Networks Operations, Inc., a Delaware corporation, with
offices at 2092 Gaither Road, Rockville, MD 20850 ("Licensor"), and "_______"
with offices at _________ ("Escrow Agent").

                                    RECITALS

      WHEREAS, Cisco and Licensor have entered into that certain OEM Agreement
dated December 3, 2002 between the parties (the "License Agreement") whereby
Licensor has licensed to Cisco certain Software (as defined in the License
Agreement);

      WHEREAS, Licensor desires to provide assurance to Cisco that Cisco can use
and distribute the Software as licensed under the License Agreement by providing
Cisco with all of the materials identified in Attachment A hereto (collectively
referred to as the "Escrow Materials"), pursuant to the release conditions set
forth herein;

      WHEREAS, Licensor desires to enter into an escrow arrangement with Cisco
to provide for the deposit of the Escrow Materials and related documentation to
be held by Escrow Agent pursuant to all of the terms and conditions of this
Escrow Agreement;

      WHEREAS, Escrow Agent is willing to act as escrow agent for Cisco and
Licensor on the terms and conditions set forth herein;

      WHEREAS, Cisco and Licensor desire this Escrow Agreement to be
supplementary to the License Agreement pursuant to 11 U.S.C. Section 365(n); and

      WHEREAS, all capitalized terms not defined herein shall have the meanings
set forth in the License Agreement.

                                    AGREEMENT

      NOW, THEREFORE, IN CONSIDERATION OF THE MUTUAL COVENANTS, AGREEMENTS AND
CONDITIONS SET FORTH HEREIN, THE PARTIES AGREE AS FOLLOWS:

1. Appointment. Cisco and Licensor hereby appoint Escrow Agent as the escrow
holder under this Escrow Agreement, and Escrow Agent accepts such appointment on
the terms and conditions set forth herein.

2. Deposit of Escrow Materials. Licensor shall deposit with Escrow Agent, within
five (5) business days after execution of this Escrow Agreement one (1) complete
copy of the Escrow Materials. Licensor further agrees to deposit one (1)
complete copy of all Software updates, error corrections, enhancements and
modifications (collectively, "Updates") within fifteen (15) days after Licensor
provides such Updates to Cisco in accordance with the License Agreement. Cisco,
after written notice to Licensor, may request that Escrow Agent inspect the
Escrow Materials deposited by Licensor with Escrow Agent for the sole purpose of
determining the existence and completeness of the deposited Escrow Materials;
provided, however, that such inspection must be conducted on or at Escrow
Agent's premises and in the presence of a Licensor representative. Licensor
shall use its diligent efforts to make such representative available to
facilitate any inspection requested by Cisco hereunder. Cisco shall have no
right to be present at such inspections.

                                                                   Page 33 of 47
<PAGE>

3. Purpose. The Escrow Materials shall constitute a reserve to be made available
to Cisco, under the terms of this Escrow Agreement, only upon the occurrence of
one of the events set forth herein. Cisco's use of the Escrow Materials released
pursuant to this Agreement shall be as set forth in Section 5 below. Escrow
Agent shall hold and dispose of the Escrow Materials only in accordance with the
terms of this Escrow Agreement and the License Agreement.

      Licensor hereby transfers title to the tangible embodiments of the Escrow
Materials to the Escrow Agent; provided, however, that: (i) the Escrow Agent
shall hold the Escrow Materials subject to all terms of this Escrow Agreement;
(ii) the Escrow Agent shall not acquire any right or interest in any of the
Intellectual Property Rights embodied in the Escrow Materials; and (iii) upon
return to Licensor of the Escrow Materials in accordance with the terms of this
Escrow Agreement, the Escrow Agent shall reconvey title thereto to Licensor.

4. Releasing Events. The deposited Escrow Materials will be delivered to Cisco
by Escrow Agent upon the earliest of one of the events set forth below:

      (a) If Licensor discontinues its maintenance and/or support of the
Software or if Cisco reasonably deems itself insecure with respect to Licensor's
ability to continue to maintain and support the Software in accordance with the
License Agreement; or

      (b) If Licensor assigns, transfers or delegates its rights and obligations
under the License Agreement to a direct competitor of Cisco without Cisco's
prior written consent, including without limitation any transfer by sale, merger
or other working combination of ownership of or control over more than twenty
percent (20%) of the voting securities or control of Licensor; or

      (c) If (a) a receiver is appointed for Licensor or its property; (b)
Licensor makes a general assignment for the benefit of its creditors; (c)
Licensor commences, or has commenced against it, proceedings under any
bankruptcy, insolvency or debtor's relief law, which proceedings are not
dismissed within sixty (60) days; or (d) Licensor is liquidated or dissolved.

5. Use of Escrow Materials. Licensor hereby grants Cisco and its Affiliates a
worldwide, nonexclusive, nontransferable, irrevocable right and license to use
the Escrowed Materials in connection with Cisco's continued marketing,
distribution and support of the Software pursuant to Section 2 of the License
Agreement ("Escrow License Rights"), which Cisco may exercise at any time upon
the occurrence of any of the events set forth in paragraph 4. For the avoidance
of doubt, with respect to any distribution of the Software pursuant to this
Section 5, Cisco shall continue to pay to Licensor the fees related thereto
pursuant to Exhibit A of the License Agreement.

6. Escrow Release. Subject to the provisions of Sections 7, 8, and 9 below,
Escrow Agent shall be authorized to release the Escrow Materials to Cisco upon
receiving written authorization from Cisco certifying that Cisco is entitled to
the Escrow Materials (the "Notice") pursuant to Section 4 above. Cisco will
include specific instructions to the Escrow Agent for this delivery.

7. Counternotice. Within three (3) business days after receipt of the Notice,
Escrow Agent shall deliver to Licensor a copy of the Notice and shall confirm
such delivery in writing to Cisco. If Escrow Agent, within five (5) business
days after delivery of the Notice by Escrow Agent to Licensor, does not receive
(a) a written statement from Cisco withdrawing such notice, or (b) a
counternotice from Licensor detailing the circumstances which it believes
indicate that the release conditions specified by Cisco did not occur
("Counternotice"), then Escrow Agent shall promptly deliver the Escrow Materials
to Cisco.

8. Disputed Notice. If Licensor disputes the existence of the conditions upon
which the Notice is based, then Licensor shall, within five (5) business days
following its receipt of Notice, submit a Counternotice to Escrow Agent. If the
Counternotice is received by Escrow Agent before the close of business on the
fifth (5th) business day following receipt of the Notice by Licensor, then
Escrow Agent shall, within three (3) business days after receipt of the
Counternotice, serve a copy of the Counternotice on Cisco and withhold delivery
of the Escrow Materials pending receipt of (a) a decision evidencing the outcome
of the arbitration provided for in Section 9 below, or (b)

                                                                   Page 34 of 47
<PAGE>

other written instructions signed by both Licensor and Cisco. Upon receipt of
said decision or other instruction, Escrow Agent shall deliver a copy of the
Escrow Materials only in accordance with the decision or instruction.

9. Arbitration.

      (a) Licensor and Cisco agree that, if the Counternotice is given by
Licensor pursuant to Section 7 above, then the parties shall submit the dispute
to expedited binding arbitration in New York City, New York, under the
Commercial Arbitration Rules of the American Arbitration Association (AAA) by
one (1) arbitrator appointed in accordance with said rules. Judgment on the
award rendered by the arbitrator may be entered in any court having jurisdiction
thereof. The sole question before the arbitrator shall be whether there existed,
at the time Cisco transmitted the Notice to Escrow Agent, the conditions
permitting release of the Escrow Materials. The parties agree that the decision
of the arbitrator shall be final and binding and that this decision shall be
immediately delivered to the parties to the arbitration and to Escrow Agent. If
the arbitrator finds that the Notice was properly given by Cisco, then Escrow
Agent shall promptly and immediately release the Escrow Materials to Cisco. If
the arbitrator finds to the contrary, then Escrow Agent shall not release the
Escrow Materials. All fees and charges by the American Arbitration Association
shall be paid by the nonprevailing party in the arbitration. Additionally, the
prevailing party in any legal action brought by one party against the other and
arising out of this Agreement will be entitled, in addition to any other rights
and remedies it may have, to reimbursement for its expenses, including
reasonable attorneys' fees. All costs of the arbitration incurred by Escrow
Agent, including reasonable attorneys' fees and costs, shall be paid by the
party which does not prevail in the arbitration, or as otherwise agreed by the
Cisco and Licensor.

      (b) Except with regard to matters involving equitable remedies, any
dispute or claim arising out of or in connection with this Escrow Agreement will
be finally settled by expedited binding arbitration in New York City, New York
under the rules of the AAA as set forth in Section 9(a) above. Notwithstanding
the foregoing, the parties may apply to any court of competent jurisdiction for
injunctive relief without breach of this arbitration provision.

10. Termination. This Escrow Agreement and the escrow established pursuant to
this Escrow Agreement shall terminate upon (a) notice of such termination by
Cisco, or (b) three (3) years after the termination of the License Agreement,
and all materials comprising the Escrow Materials shall thereupon be returned to
Licensor. Cisco shall notify Escrow Agent upon termination of this Escrow
Agreement or the License Agreement.

11. Notices.

      11.1 No Liability. It is agreed that Escrow Agent will incur no liability
for acting upon any instruction, notice, direction or other document believed by
it in good faith to be genuine and to have been made, signed, sent or presented
by the person or persons authorized to perform such act under the terms of this
Escrow Agreement.

      11.2 Delivery. All notices, instructions, deliveries and other
communications required or permitted to be given hereunder or necessary or
convenient in connection herewith shall be in writing and shall be deemed to
have been given when personally delivered, when sent by facsimile, telex, or
telegram, or (3) days after mailing if mailed by registered or certified mail,
return receipt requested, as follows (provided that notice of change of address
shall be deemed given only when received):

To Escrow Agent:  To the address first set forth above, and to the attention of
                  the person signing this Escrow Agreement on behalf of Escrow
                  Agent.

To Licensor:      To the address first set forth above, with a copy to Visual
                  Networks Operations, Inc., Attn: Corporate Counsel, 2092
                  Gaither Road, Rockville, MD 20850.

To Cisco:         To the address first set forth above, with a copy to Cisco
                  Systems, Inc., Attn: VP Legal Services and General Counsel,
                  170 West Tasman Drive, San Jose, CA 95134.

or to such other name or address as Escrow Agent, Licensor or Cisco, as the case
may be, shall designate by notice to the other parties hereto in the manner
specified in this section.

                                                                   Page 35 of 47
<PAGE>

12. Liability of Escrow Agent. The duties and obligations of Escrow Agent shall
be determined solely by the express provisions of this Escrow Agreement, and
Escrow Agent shall not be liable except for the performance of such duties and
obligations as are specifically set forth in this Escrow Agreement. In the event
of any controversy hereunder or with respect to any questions as to the
construction of this Escrow Agreement or any action to be taken by Escrow Agent,
Escrow Agent may, at its expense, consult with counsel selected and employed by
it, and Escrow Agent shall incur no liability for any action taken or suffered
in good faith in accordance with the good faith opinion of such counsel. Escrow
Agent shall not be responsible in any manner whatsoever for any failure or
inability of Licensor, Cisco or anyone else to perform or comply with any of the
provisions of this Escrow Agreement.

13. Governing Law. This Escrow Agreement will be governed by the laws of the
State of New Yorkwithout reference to conflict of laws principles.

14. Entire Agreement. This Escrow Agreement and the License Agreement sets forth
the entire understanding of the parties hereto with respect to the subject
matter hereof and cannot be changed, modified, or terminated orally.

15. Validity. No action taken by Escrow Agent in accordance with the terms and
provisions hereof shall be deemed to constitute a representation of Escrow Agent
as to the validity or value of any documents or instructions held by, or
delivered to, it.

16. Resignation/Replacement.

      16.1 Resignation. Upon sixty (60) days' prior written notice given to
Licensor and Cisco, Escrow Agent may resign. Within fifteen (15) days after the
giving of such notice, Licensor and Cisco shall mutually designate a successor
escrow agent. Such successor escrow agent shall be bound by the terms and
provisions of this Escrow Agreement. In the event that no such agreement is
reached within such fifteen (15) day period, Escrow Agent shall continue to hold
the Escrow Materials then held by it until a successor can be found. Escrow
Agent shall cooperate with its successor in order to effectuate the transfer of
its duties to the successor escrow agent.

      16.2 Replacement. Upon ninety (90) days' written notice to Escrow Agent,
Licensor and Cisco may mutually agree to replace Escrow Agent with a successor
and such successor shall be bound by all the terms and conditions of this Escrow
Agreement.

17. Fees and Expenses. Cisco shall pay the fees of Escrow Agent for its services
hereunder during the term of this Escrow Agreement. Such fees shall consist of
initiation fees, periodic escrow maintenance charges, at Escrow Agent's standard
rates, fees charged for carrying out its duties hereunder. Escrow Agent's
current schedule of fees for the first year of this Agreement is attached hereto
as Attachment B. Escrow Agent shall have no obligation under this Agreement
until the initial invoice has been paid in full.

18. Indemnification. Licensor and Cisco jointly and severally agree to indemnify
Escrow from and against any and all third party liabilities, claims, suits and
other proceedings, all judgments and other awards against Escrow Agent in
connection herewith, and all costs and expenses incurred in connection with the
defense thereof, in each case which may be imposed on, or incurred by, or
asserted against, Escrow Agent in any way relating to, or arising out of, this
Escrow Agreement, or any action taken or omitted by Escrow Agent under this
Escrow Agreement, provided that neither Licensor nor Cisco shall be liable for
that portion of any such indemnification amount resulting from Escrow Agent's
gross negligence or willful misconduct or violation by Escrow Agent of any terms
or provisions of this Escrow Agreement.

19. Limitation of Liability. Except for intentional misrepresentation, gross
negligence or intentional misconduct, Escrow Agent shall not be liable to Cisco
or Licensor for any act, or failure to act, by Escrow Agent in connection with
this Agreement. Escrow Agent will not be liable for special, indirect,
incidental or consequential damages hereunder.

20. Counterparts. This Escrow Agreement may be executed in two or more
counterparts, each of which shall be deemed an original and all of which
together shall constitute one instrument.

                                                                   Page 36 of 47
<PAGE>

21. Modification. No modifications to this Escrow Agreement, nor any waiver of
any rights, shall be effective unless assented to in writing by the party to be
charged and the waiver of any breach or default shall not constitute a waiver of
any other right hereunder or any subsequent breach or default.

      IN WITNESS WHEREOF, the parties by their duly authorized representatives
have executed this Escrow Agreement as of the date set forth above.

CISCO SYSTEMS, INC.                      VISUAL NETWORKS OPERATIONS, INC.

By:                                      By:
   ----------------------------             ------------------------------
Name:                                    Name:
     --------------------------               ----------------------------
Title:                                   Title:
      -------------------------                ---------------------------
Date:                                    Date:
     --------------------------               ----------------------------

-------------------------------
"Escrow Agent"

By:
   ----------------------------
Name:
     --------------------------
Title:
      -------------------------
Date:
     --------------------------

                                                                   Page 37 of 47
<PAGE>

                                  ATTACHMENT A

                                ESCROW MATERIALS

[***]

***   Confidential Information has been omitted and filed separately with the
      Securities and Exchange Commission pursuant to a confidential treatment
      request.

                                                                   Page 38 of 47
<PAGE>

                                  ATTACHMENT B

                     ESCROW AGENT'S CURRENT SCHEDULE OF FEES

                                                                   Page 39 of 47
<PAGE>

                                    EXHIBIT I

                                END USER LICENSE

SOFTWARE LICENSE AGREEMENT

YOU SHOULD CAREFULLY READ THE FOLLOWING TERMS AND CONDITIONS BEFORE LOADING THIS
SOFTWARE. LOADING THIS SOFTWARE INDICATES YOUR ACCEPTANCE OF THESE TERMS AND
CONDITIONS. IF YOU DO NOT AGREE WITH THEM, YOU SHOULD PROMPTLY RETURN THE
SOFTWARE PACKAGE AND YOUR MONEY PAID WILL BE REFUNDED.

This Software License Agreement (the "Agreement") grants you a non-exclusive
license to use the software supplied to you by Visual Networks, Inc. ("VISUAL"),
including the software supplied to you on disks, diskettes, on-line, and/or as
part of the equipment supplied by VISUAL and any modifications, enhancements to
and/or replacements of such software supplied to you by VISUAL (collectively the
"Software") in return for payment of a license fee. This Agreement imposes
certain restrictions on the use of the Software. VISUAL retains ownership of the
Software and no rights are granted to you other than a license to use the
Software on the terms expressly set forth in this Agreement.

Permitted Uses

You may make one (1) copy of the Software for backup purposes only. You may
install and use one copy of Visual's server and console products. Per the
conditions of your specific purchase agreement with Visual, you may install
multiple copies of the client code component of Visual's product. You must
reproduce and place all copyright/proprietary/patent notices on the backup copy,
as indicated on the original. If the Software is an upgrade, you may now use
that upgraded product only in accordance with this Agreement.

Restricted Uses

Without the express written consent of VISUAL, you may not:

1. Use, copy (other than then as described above), modify, distribute, reverse
engineer, reverse assemble, or reverse compile the Software or accompanying
documentation except as expressly allowed in this Agreement.

2. Transfer or assign your rights to use the Software except upon a transfer of
any VISUAL equipment with which or for which it was supplied, and then only if
VISUAL receives written agreement of the transferee to be bound by all of the
terms of this Agreement.

3. Sublicense or lease this Software or its documentation.

Term

This license is effective from your date of purchase and shall remain in force
until terminated. You may terminate this license and Agreement by destroying the
Software and its documentation, together with all copies in any form or by
returning to VISUAL, the Software and its documentation, together with all
copies in any form. This Agreement will also terminate if you fail to comply
with any term of this Agreement. You agree upon any such termination to either
(i) destroy the Software and documentation, together with all copies in any form
or (ii) return to VISUAL the Software and its documentation, together with all
copies in any form.

Exclusion of Warranty

                                                                   Page 40 of 47
<PAGE>

THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE
QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU.

Intellectual Property Indemnity

VISUAL will defend, at its own expense, any claim, suit or proceeding brought
against you to the extent it is based upon a claim that the Products infringe
upon any patent, copyright or trade secret of any third party. You agree that
you shall promptly notify VISUAL in writing of any such claim or action and give
VISUAL full information and assistance in connection therewith. VISUAL shall
have the sole right to control the defense of any such claim or action and the
sole right to settle or compromise any such claim or action. If you comply with
the provisions hereof, VISUAL will pay all damages, costs and expenses finally
awarded by court order or final settlement to third parties against you in such
action. VISUAL will have no liability for any claim of infringement arising as a
result of your sale or use of a Product in combination with any items not
supplied by VISUAL or any modification of a Product by you or third parties. THE
FOREGOING STATES THE ENTIRE LIABILITY OF VISUAL TO YOU CONCERNING INFRINGEMENT
OF INTELLECTUAL PROPERTY RIGHTS, INCLUDING BUT NOT LIMITED TO PATENT, COPYRIGHT
AND TRADE SECRET RIGHTS.

LIMITATION ON LIABILITY

IN NO EVENT SHALL VISUAL, ITS SELLING REPRESENTATIVES, DEALERS OR DISTRIBUTORS,
BE LIABLE FOR LOST PROFITS, DATA OR INFORMATION OF ANY KIND OR FOR
CONSEQUENTIAL, SPECIAL, INDIRECT, INCIDENTAL, PUNITIVE OR OTHER DAMAGES THAT MAY
ARISE THROUGH THE SALE OF, USE OF, OR INABILITY TO USE ANY VISUAL PRODUCT OR
SERVICE, EVEN IF VISUAL HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
CUSTOMERS SOLE AND EXCLUSIVE REMEDY FOR ANY DAMAGE OR LOSS IN ANY WAY IN
CONNECTION WITH THE PRODUCTS, INCLUDING, BUT NOT LIMITED TO, THE INSTALLATION
AND MAINTENANCE THEREOF, SHALL BE AT VISUAL'S OPTION: (I) REPAIR OR REPLACEMENT
OF THE RELEVANT PRODUCT, OR IN THE CASE OF INSTALLATION OR MAINTENANCE THE
REPERFORMANCE OF THE INSTALLATION OR MAINTENANCE, RESPECTIVELY, OR (II) RETURN
OF THE MONIES PAID BY YOU TO VISUAL FOR THE RELEVANT PRODUCT OR INSTALLATION OR
MAINTENANCE.

                                                                   Page 41 of 47
<PAGE>

                                    EXHIBIT J

                            NON-DISCLOSURE AGREEMENT

This Non-Disclosure Agreement ("Agreement") is entered into as of the date last
written below between Cisco Systems, Inc. a California corporation having its
principal place of business at 170 West Tasman Drive, San Jose, California
95134-1706 and its affiliates (Cisco Systems, Inc. and its affiliates
collectively referred to herein as "Cisco") and Visual Networks Operations,
Inc., a Delaware corporation having its principal place of business at 2092
Gaither Road, Rockville, Maryland 20850.

In consideration of the mutual promises and covenants contained in this
Agreement and the disclosure of confidential information to each other, the
parties to this Agreement agree as follows:

1. DEFINITION. "Confidential Information" means the terms and conditions of this
Agreement, the existence of the discussions between the parties, the information
described in Section 2 below, and any other information concerning the Purpose
defined below, including but not limited to, information regarding each party's
product plans, product designs, product costs, product prices, finances,
marketing plans, business opportunities, personnel, research and development
activities, know-how and pre-release products; provided that information
disclosed by the disclosing party ("Disclosing Party") in written or other
tangible form will be considered Confidential Information by the receiving party
("Receiving Party") only if such information is conspicuously designated as
"Confidential," "Proprietary" or a similar legend. Information disclosed orally
shall only be considered Confidential Information if: (i) identified as
confidential, proprietary or the like at the time of disclosure, and (ii)
confirmed in writing within thirty (30) days of disclosure. Confidential
Information disclosed to the Receiving Party by any affiliate or agent of the
Disclosing Party is subject to this Agreement.

2. DESCRIPTION. The Confidential Information to be disclosed under this
Agreement is information related to the OEM Agreement dated December 3, 2002
between the parties.

3. PURPOSE. The Receiving Party may use the Confidential Information solely for
the purpose of ("Purpose"):

Exercising its rights and performing its obligations under the OEM Agreement
dated December 3, 2002 between the parties.

4. DISCLOSURE. The Receiving Party shall not disclose the Confidential
Information to any third party other than employees and contractors of the
Receiving Party who have a need to have access to and knowledge of the
Confidential Information solely for the Purpose authorized above. The Receiving
Party shall have entered into non-disclosure agreements with such employees and
contractors having obligations of confidentiality as strict as those herein
prior to disclosure to such employees and contractors to assure against
unauthorized use or disclosure.

5. EXCEPTIONS TO CONFIDENTIAL INFORMATION. The Receiving Party shall have no
obligation with respect to information which (i) was rightfully in possession of
or known to the Receiving Party without any obligation of confidentiality prior
to receiving it from the Disclosing Party; (ii) is, or subsequently becomes,
legally and publicly available without breach of this Agreement; (iii) is
rightfully obtained by the Receiving Party from a source other than the
Disclosing Party without any obligation of confidentiality; (iv) is developed by
or for the Receiving Party without use of the Confidential Information and such
independent development can be shown by documentary evidence; (v) becomes
available to the Receiving Party by wholly lawful inspection or analysis of
products offered for sale; and (vi) is transmitted by a party more than five (5)
business days after receiving written notification from the other party that it
does not desire to receive any further Confidential Information. Further, the
Receiving Party may disclose Confidential Information pursuant to a valid order
issued by a court or government

                                                                   Page 42 of 47
<PAGE>

agency, provided that, to the extent possible, the Receiving Party provides the
Disclosing Party: (a) prior written notice of such obligation; and (b) the
opportunity to oppose such disclosure or obtain a protective order.

6. RETURN OR DESTRUCTION OF CONFIDENTIAL INFORMATION. Upon written demand by the
Disclosing Party, the Receiving Party shall: (i) cease using the Confidential
Information, (ii) return the Confidential Information and all copies, notes or
extracts thereof to the Disclosing Party within seven (7) days of receipt of
demand; and (iii) upon request of the Disclosing Party, certify in writing that
the Receiving Party has complied with the obligations set forth in this
paragraph.

7. INDEPENDENT DEVELOPMENT AND RESIDUALS. The terms of confidentiality under
this Agreement shall not be construed to limit either party's right to develop
independently or acquire products without use of the other party's Confidential
Information. The Disclosing Party acknowledges that the Receiving Party may
currently or in the future be developing information internally, or receiving
information from other parties, that is similar to the Confidential Information.
Accordingly, nothing in this Agreement will prohibit the Receiving Party from
developing or having developed for it products, concepts, systems or techniques
that are similar to or compete with the products, concepts, systems or
techniques contemplated by or embodied in the Confidential Information provided
that the Receiving Party does not violate any of its obligations under this
Agreement in connection with such development. Further, subject to Section 8,
the residuals resulting from access to or work with such Confidential
Information shall not be subject to the confidentiality obligations contained in
this Agreement. The term "residuals" means information in non-tangible form,
which may be retained in the unaided memories of persons who have had access to
the Confidential Information, including ideas, concepts, know-how or techniques
contained therein. A person's memory is unaided if the person has not
intentionally memorized the Confidential Information for the purpose of
retaining and subsequently using or disclosing it. Neither party shall have any
obligation to limit or restrict the assignment of such persons or to pay
royalties for any work resulting from the use of residuals.

8. NO LICENSES. Each party shall retain all right, title and interest to such
party's Confidential Information. No license under any trademark, patent or
copyright, or application for same which are now or thereafter may be obtained
by such party is either granted or implied by the disclosure of Confidential
Information.

9. DISCLAIMER. CONFIDENTIAL INFORMATION IS PROVIDED "AS IS" WITH ALL FAULTS. IN
NO EVENT SHALL THE DISCLOSING PARTY BE LIABLE FOR THE ACCURACY OR COMPLETENESS
OF THE CONFIDENTIAL INFORMATION.

None of the Confidential Information disclosed by the parties constitutes any
representation, warranty, assurance, guarantee or inducement by either party to
the other with respect to the infringement of trademarks, patents, copyrights,
any right of privacy, or any rights of third persons.

10. EXPORT. The parties acknowledge that the Confidential Information disclosed
by each of them under this Agreement may be subject to export controls under the
laws of the United States. Each party shall comply with such laws and agrees not
to knowingly export, re-export or transfer Confidential Information of the other
party without first obtaining all required United States authorizations or
licenses.

11. TERM. This Agreement shall continue from the date last written below until
terminated by either party by giving thirty (30) days written notice to the
other party of its intent to terminate this Agreement. Notwithstanding such
termination, the obligations of the Receiving Party concerning confidentiality
shall terminate five (5) years following receipt of the Confidential
Information.

12. GENERAL. Each party acknowledges that monetary remedies may be inadequate to
protect Confidential Information and that injunctive relief may be appropriate
to protect such Confidential Information.

The Receiving Party shall not reverse-engineer, decompile, or disassemble any
software disclosed to it under this Agreement and shall not remove, overprint or
deface any notice of confidentiality, copyright, trademark, logo, legend or
other notices of ownership or confidentiality from any originals or copies of
Confidential Information it obtains from the Disclosing Party.

                                                                   Page 43 of 47
<PAGE>

The parties hereto are independent contractors. Neither this Agreement nor any
right granted hereunder shall be assignable or otherwise transferable.

If any term of this Agreement shall be held to be illegal or unenforceable by a
court of competent jurisdiction, the remaining terms shall remain in full force
and effect.

This Agreement may be modified only by a writing signed by both parties.

This Agreement shall be construed in accordance with the laws of the State of
New York.

This Agreement represents the entire agreement of the parties hereto pertaining
to the subject matter of this Agreement, and supersedes any and all prior oral
discussions and/or written correspondence or agreements between the parties with
respect thereto.

IN WITNESS WHEREOF, the parties have executed this Agreement as of the date last
written below.

CISCO SYSTEMS, INC.                 VISUAL NETWORKS OPERATIONS, INC.

By __________________________       By  _____________________________

Name_________________________       Name_____________________________

Title _______________________       Title____________________________

Date_________________________       Date ____________________________

                                                                   Page 44 of 47
<PAGE>

                                    EXHIBIT K

                        MARKETING & DEPLOYMENT GUIDELINES

This Exhibit specifies marketing and deployment criteria for activities required
to bring to market, install and maintain the products and solutions in this
Agreement. Details per project will be stipulated in the Statements of Work.

The parties agree to engage in the cooperative marketing and sales efforts set
forth herein to promote their respective products and the products/solutions
created through this Agreement, as mutually agreed to and when consistent with
both parties' business interests.

The following terms and conditions stipulate parties' obligations as well as the
structure of the information to be provided in the marketing and deployment
sections of each Statement of Work attached to this Agreement.

1.    Marketing

      1.1.  Obligations and Execution. The parties shall use reasonable
            commercial efforts to conduct marketing activities defined in the
            Product Requirements Document and deliver the Deliverables pursuant
            to the terms and/or conditions provided therein.

      1.2.  Activities. It is foreseen that the parties will engage in the
            following such activities:

            o     Laboratories - A demo lab will be available at Cisco for
                  supporting customer visits and an internal team of sales,
                  marketing, and TMEs who will be providing demos in the field.
                  Visual Networks will provide any required support of such
                  activities on site, as appropriate

            o     Marketing Materials, Product Information Creation, Joint
                  Collateral and Sales Tools - Cisco and Visual Networks will
                  jointly develop such information and materials (as data
                  sheets, customer success stories, web-enabled information
                  etc.) with the intent of using uniquely the Cisco brand by the
                  second release of WAPMS

            o     Joint Sales Calls - Initially led by Visual Networks, Cisco
                  and Visual will jointly attend sales calls and visits and
                  support RFP responses, with the intent of training Cisco sales
                  people on selling the WAPMS solution

            o     Advertising and Media Campaigns - Cisco and Visual Networks
                  will jointly establish and advertising and media strategy
                  including but not limited to press releases, video/multimedia
                  presentations, interviews, and placement of advertisements in
                  print, online, radio, television media.

            o     Customer Training, Seminars and Forums - All customer
                  training, seminars and forums will be driven and coordinated
                  through the Cisco INSMBU Residency Program. Cisco and Visual
                  Networks will work together to develop content and schedule
                  activities. Deliverables include but are not limited to: SEVT
                  training and product demo, pre-launch presentations to Cisco's
                  Sales team members, technical publications, solution
                  deployment documentation, and white papers

            o     Participate in Trade Shows and Conferences - Cisco and Visual
                  Networks will establish a one-year moving schedule of trade
                  shows and events in which they will jointly participate to
                  market the WAPMS solution

            o     Web-enabled Information Sharing, Exchanging and/or
                  Cross-referencing - Cisco and Visual Networks will share
                  appropriate online information and cross-reference each
                  other's web sites as appropriate. Over time, a Cisco web area
                  will be developed to support the majority of field information
                  requirements

                                                                   Page 45 of 47
<PAGE>

      1.3.  Description of Tasks and Responsibilities. Set forth in each
            Statement of Work, the parties will undertake and provide a detailed
            description of the tasks and responsibilities for each party
            therefor, including a reasonably detailed target schedule for
            marketing activities, deliverables and fulfillment of the parties'
            responsibilities including but not limited to the activities listed
            in Section 1.2 of this Exhibit..

      1.4.  Product Requirements Information Exchange. Cisco and Visual Networks
            agree to disclose to one another information, which may be in the
            form of an Agent Development Kit or a Software Development Kit, a
            Product Requirements Document, Statements of Work in the format of
            Exhibits attached to this Agreement, email or other communication
            that will facilitate the integration of Cisco products and Visual
            Networks products that they mutually desire and agree to be
            integrated. Examples of information that will be disclosed to one
            another include:

            o     Any proposed or mutually agreed interface or protocol
                  specifications (as used herein, "Specifications" shall mean
                  any mutually agreed written specifications relating to
                  interoperation of Cisco product and Visual Network products.)

            o     Product and/or feature requirements, specifications and
                  roadmap

            o     Application Interface specifications

            o     Listings of recommended tools needed for development and
                  testing

            o     Import/Export data format

            o     Test and interoperability functional specifications

            o     Definition and implementation of MIBs or equivalent statistics

            o     Communication protocols

      1.5   Product Marketing Contacts. The following people shall be deemed as
            primary marketing contacts with Cisco and Visual Networks

              ------------------------------------------------------------------
                                 Cisco                 Visual Networks
              ------------------------------------------------------------------
                           Joe Zhao               Robin Brown
              Name
              ------------------------------------------------------------------
              Title        Product Manager        Director, Product Management
              ------------------------------------------------------------------
              Address      170 E. Tasman Drive    10169 N. Blaney Avenue
                           San Jose, CA 95134     Cupertino, CA  95014
              ------------------------------------------------------------------
              Phone/Fax    (408) 525-9712         (408) 996-2002
              ------------------------------------------------------------------
              Email        jzhao@cisco.com        rbrown@visualnetworks.com
              ------------------------------------------------------------------

2.    Deployment

      2.1   General. Upon signature of this Agreement (or shortly before, upon
            mutual consent of the parties,) Cisco and Visual Networks agree to
            convene a team to establish a Deployment Plan including but not
            limited to defining a schedule by which the various deployment
            activities and deliverables will be executed and to participate in
            the next Cisco SEVT.

                  The Deployment Plan will cover: assess the customer
            environment; determine a standard level of preparation required
            before going to a customer site; create an on-site checklist
            including but not limited to such items as: loading sequence, test
            criteria, success factors; partner qualification and training
            guidelines; analyze and resolve any potential channel conflicts,
            design customer training; and a back-up support plan.

      2.3   Cisco Deliverables and Resources. Cisco will provide hardware
            resources for testing and demos, lab space, testing Program
            Management, and training program development leadership.

                                                                   Page 46 of 47
<PAGE>

      2.4   Visual Networks Deliverables and Resources. Visual Networks will
            provide content for the Deployment and Installation guides, subject
            matter expertise for designing customer scenarios and support Cisco
            in the building of a 4-day training course. Visual Networks will
            provide personnel, as necessary, to support the teaching effort
            during the 4-day training seminar and a TME. For the EFT, mentioned
            below, Visual Networks will provide a support plan, user guide,
            engineering support, and any on-site support required by the EFT
            customer.

      2.5   Initial Phases. Initially, 2 Phases of deployment shall be defined.
            These phases are intended to provide a clear path to meeting
            short-term time-to-market minimal requirements (in Phase 1) and to
            provide for a more complete deployment process in (Phase 2). More
            phases may be established through execution of these initial Phases
            as feedback is collected and demand for deployment services is more
            clearly defined.

            2.5.1 Phase 1 deliverables shall be defined as a Deployment Guide
                  and an Installation Guide with Cisco Branding, knowledge
                  transfer between the parties, and an Early Field Trail (EFT)
                  using an event gateway on the Windows 2000 platform.

            2.5.2 Phase 2 deliverables will be defined as updated Deployment and
                  Installation Guides, fully developed demos, testing plans
                  complete, testing and demo labs in place and staffed,
                  configuration scenarios defined for training purposes and a
                  4-day course developed.

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