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                                                                   EXHIBIT 10.25

                     ACCOUNTS RECEIVABLE FINANCING AGREEMENT


        This ACCOUNTS RECEIVABLE FINANCING AGREEMENT (the "Agreement") dated as
of February 28, 2001, is between SILICON VALLEY BANK, a California-chartered
bank, with its principal place of business at 3003 Tasman Drive, Santa Clara,
California 95054 and with a loan production office located at One Newton
Executive Park, Suite 200, 2221 Washington Street, Newton, Massachusetts 02462,
doing business under the name "Silicon Valley East" ("Lender"), and (i) VISUAL
NETWORKS, INC., a Delaware corporation, (ii) VISUAL NETWORKS OPERATIONS, INC., a
Delaware corporation, (iii) VISUAL NETWORKS INVESTMENTS, INC., a California
corporation, (iv) VISUAL NETWORKS TECHNOLOGIES, INC., a California corporation,
(v) VISUAL NETWORKS OF TEXAS, L.P., a Texas limited partnership, (vi) VISUAL
NETWORKS INSURANCE, INC., a Vermont corporation, (vii) INVERSE NETWORK
TECHNOLOGY, a California corporation, and (viii) AVESTA TECHNOLOGIES, INC., a
Delaware corporation (jointly, severally and collectively, the "Borrower").

1.      DEFINITIONS.  In this Agreement:

        "ACCOUNTS" are all existing and later arising accounts, contract rights,
and other obligations owed Borrower in connection with its sale or lease of
goods (including licensing software and other technology) or provision of
services, all credit insurance, guaranties, other security and all merchandise
returned or reclaimed by Borrower and Borrower's Books relating to any of the
foregoing.

        "ACCOUNT BALANCE" is the aggregate outstanding Advances made hereunder.

        "ACCOUNT DEBTOR" is as defined in the Code and shall include, without
limitation, any person liable on any Financed Receivable, such as, a guarantor
of the Financed Receivable and any issuer of a letter of credit or banker's
acceptance.

        "ADJUSTMENTS" are all discounts, allowances, returns, disputes,
counterclaims, offsets, defenses, rights of recoupment, rights of return,
warranty claims, or short payments, asserted by or on behalf of any Account
Debtor for any Financed Receivable.

        "ADVANCE" is defined in Section 2.2.

        "ADVANCE RATE" is eighty percent (80%), net of customer specific offsets
related to maintenance billings and customer deposits, provided, however, that
so long as the Borrower retains a Quick Ratio of 1.5:1.0 or greater, no such
offsets shall be applied to calculate the Advance Rate.

        "APPLICABLE RATE" is a per annum rate equal to the "Prime Rate" plus two
percentage points (2.0%).

        "BORROWER'S BOOKS" are all Borrower's books and records including
ledgers, records regarding Borrower's assets or liabilities, the Collateral,
business operations or financial condition and all computer programs or discs or
any equipment containing the information.

        "CODE" is the Uniform Commercial Code as adopted by The Commonwealth of
Massachusetts (presently, Mass. Gen. Laws, Ch. 106), as may be amended and in
effect from time to time.

        "COLLATERAL" is described on EXHIBIT "A".

        "COLLATERAL HANDLING FEE" is defined in Section 3.5.

        "COLLECTIONS" are all funds received by Lender from or on behalf of an
Account Debtor for Financed Receivables.



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        "COMPLIANCE CERTIFICATE" is attached as EXHIBIT "C".

        "CURRENT LIABILITIES" are the aggregate amount of Borrower's Total
Liabilities which mature within one (1) year (excluding all deferred revenue),
which shall include, without limitation, all obligations and liabilities of
Borrower to Lender.

        "EVENT OF DEFAULT" is defined in Section 9.

        "FACILITY" is an extension of credit by Lender to Borrower in order to
finance Receivables with an aggregate Account Balance not exceeding the Facility
Amount.

        "FACILITY AMOUNT" is Ten Million Dollars ($10,000,000.00).

        "FACILITY FEE" is defined in Section 3.3.

        "FACILITY PERIOD" is the period beginning on this date and continuing
until February __, 2002, unless the period is terminated sooner by Lender with
notice to Borrower or by Borrower pursuant to the terms of this Agreement.

        "FINANCE CHARGES" is defined in Section 3.2.

        "FINANCED RECEIVABLES" are Receivables which Lender finances by making
an Advance in accordance with this Agreement. A Financed Receivable stops being
a Financed Receivable (but remains Collateral) when the Advance made for the
Financed Receivable has been finally paid.

        "FINANCED RECEIVABLE BALANCE" is the total outstanding amount, at any
time, of all Financed Receivables.

        "GUARANTOR" means any future guarantor of the Obligations, to the extent
as may hereafter be applicable.

        "INELIGIBLE RECEIVABLE" is any Receivable:

               (a)    that is unpaid (90) calendar days after the invoice date;
                      or

               (b)    that is owed by an Account Debtor that has filed, or has
                      had filed against it, any bankruptcy case, assignment for
                      the benefit of creditors, receivership, or Insolvency
                      Proceeding or who has become insolvent (as defined in the
                      United States Bankruptcy Code) or who is generally not
                      paying its debts as they become due; or

               (c)    for which there has been any breach of warranty or
                      representation in Section 6 or any breach of any covenant
                      in this Agreement; or

               (d)    for which the Account Debtor asserts any discount,
                      allowance, return, dispute, counterclaim, offset, defense,
                      right of recoupment, right of return, warranty claim, or
                      short payment; or

               (e)    that has been modified after the Invoice Transmittal has
                      been delivered to Lender, without Lender's written
                      consent.

        "INSOLVENCY PROCEEDING" are proceedings by or against any person under
the United States Bankruptcy Code, or any other bankruptcy or insolvency law,
including assignments for the benefit of creditors, compositions, extensions
generally with its creditors, or proceedings seeking reorganization,
arrangement, or other similar relief.


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        "INVOICE TRANSMITTAL" shows Receivables which Lender may finance and,
for each Receivable, includes the Account Debtor's, name, address, invoice
amount, invoice date and invoice number and is signed by Borrower's authorized
representative.

        "LOAN AGREEMENT" means a certain Loan and Security Agreement of even
date between the Borrower and the Bank.

        "LOCKBOX" is described in Section 6.3(J).

        "MINIMUM FINANCE CHARGE" is a minimum monthly Finance Charge of
$4,000.00 payable to the Lender.

        "NET LOSS" is a reconciled amount that is calculated as the net loss of
the Borrower (on a consolidated basis) as determined by GAAP, and adjusted by
(i) non-cash charges including, without limitation, intangible amortization and
depreciation, and (ii) non-recurring costs including, without limitation,
restructuring charges and intangible asset write-downs.

        "NET PROFIT" is a reconciled amount that is calculated as the net income
of the Borrower (on a consolidated basis) as determined by GAAP, and adjusted by
(i) non-cash charges including, without limitation, intangible amortization and
depreciation, and (ii) non-recurring costs including, without limitation,
restructuring charges and intangible asset write-downs.

        "OBLIGATIONS" are all advances, liabilities, obligations, covenants and
duties owing, arising, due or payable by Borrower to Lender now or later under
this Agreement or any other document, instrument or agreement, account
(including those acquired by assignment) primary or secondary, such as all
Advances, Finance Charges, Collateral Handling Fees, Facility Fees, interest,
fees, expenses, professional fees and attorneys' fees, or other amounts now or
hereafter owing by Borrower to Lender.

        "PRIME RATE" is Lender's most recently announced "Prime Rate," even if
it is not Lender's lowest rate.

        "QUICK ASSETS" is, on any date, the Borrower's consolidated,
unrestricted cash, cash equivalents, net billed Receivables determined according
to GAAP.

        "QUICK RATIO".  A ratio of Quick Assets to Current Liabilities.

        "RECEIVABLES" are all those accounts, receivables, chattel paper,
instruments, contract rights, documents, general intangibles, letters of credit,
drafts, bankers acceptances, and rights to payment, and all proceeds, including
their proceeds.

        "RECONCILIATION DAY" is the last calendar day of each month.

        "RECONCILIATION PERIOD" is each calendar month.

        "RESPONSIBLE OFFICER" is each of the Chief Executive Officer; President;
Chief Financial Officer; Vice President, Finance; Director, Treasury Operations;
and Controller of Agent, or of a Borrower (if appropriate).

        "SERVICE AGREEMENT" is Borrower's contract documents with its customer
containing the terms, conditions and payment obligations for use of services by
such customers.

        "TOTAL LIABILITIES" is on any day, obligations that should, under GAAP,
be classified as liabilities on Borrower's consolidated balance sheet, including
all Indebtedness.


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2.      FINANCING OF ACCOUNTS RECEIVABLE.

        2.1.    REQUEST FOR ADVANCES. So long as no Event of Default has
occurred or is continuing, Borrower may request that the Lender finance
Receivables. Borrower will deliver an Invoice Transmittal in the form attached
hereto at EXHIBIT B for each Receivable or package of Receivables it offers.
Lender may rely on information on or with such Invoice Transmittals.

        2.2.    ACCEPTANCE OF ACCOUNTS RECEIVABLE. Lender is not obligated to
finance any Receivable. Lender may review any Account Debtor's credit before
agreeing to finance any Receivable. When Lender agrees to finance a Receivable,
it will extend credit to the Borrower in an amount up to the result of the
Advance Rate multiplied by the face amount of the Receivable (the "Advance").
Such extension of credit may include the issuance of letters of credit, subject
to the terms and rates acceptable to Lender. When Lender makes an Advance, the
Receivable becomes a "Financed Receivable." All representations and warranties
in Section 6 must be true as of the date of the Invoice Transmittal and of the
Advance and no Event of Default exists would occur as a result of the Advance.
The aggregate amount of all Financed Receivables outstanding at any time may not
exceed the Facility Amount.

3.      COLLECTIONS, FINANCE CHARGES, REMITTANCES AND FEES. The Obligations
shall be subject to the following fees and Finance Charges. Fees and Finance
Charges may, in Lender's discretion, be charged as an Advance, and shall
thereafter accrue fees and Finance Charges as described below. Lender may, in
its discretion, charge fees and Finance Charges to Borrower's deposit account
maintained with Lender.

        3.1.    COLLECTIONS. Collections will be credited to the Financed
Receivables Balance, with the exception of Collections of Financed Receivables
on account of Advances used to issue letters of credit, which are undrawn or
drawn but unpaid, which collections shall be used solely to cash secure such
letters of credit, but if there is an Event of Default, Lender may apply
Collections to the Obligations in any order it chooses. If Lender receives a
payment for both a Financed Receivable and a non Financed Receivable, the funds
will first be applied to the Financed Receivable and, if there is not an Event
of Default, the excess will be remitted to the Borrower, subject to Section 3.8.

        3.2.    FINANCE CHARGES. In computing Finance Charges on the
Obligations, all Collections received by Lender shall be deemed applied by
Lender on account of the Obligations three (3) Business Days after receipt of
the Collections. Borrower will pay a finance charge (the "Finance Charge"),
except for the portion of Financed Receivable Balance which relates to letters
of credit issued by Lender, which is equal to the greater of (i) the Applicable
Rate multiplied by the number of days in the Reconciliation Period divided by
360, which is then multiplied by the outstanding average daily Financed
Receivable Balance for that Reconciliation Period, or (ii) the Minimum Finance
Charge, as and when same may be applicable. After an Event of Default,
Obligations accrue interest at five percent (5%) above the Applicable Rate
effective immediately before the Event of Default.

        3.3.    FACILITY FEE. A fully earned, non-refundable facility fee of
Fifty Thousand Dollars ($50,000.00) is due upon execution of this Agreement.

        3.4.    ACCOUNTING. After each Reconciliation Period, Lender will
provide an accounting of the transactions for that Reconciliation Period,
including the amount of all Financed Receivables, all Collections, Adjustments,
Finance Charges, Collateral Handling Fee, and the Facility Fee. If Borrower does
not object to the accounting in writing within thirty (30) days it is considered
correct. All Finance Charges and other interest and fees are calculated on the
basis of a 360 day year and actual days elapsed.

        3.5.    COLLATERAL HANDLING FEE. On each Reconciliation Day, Borrower
will pay to Lender a collateral handling fee, equal to one half of one percent
(0.50%) per month of the average daily Financed Receivable Balance


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outstanding during the applicable Reconciliation Period. After an Event of
Default, the Collateral Handling Fee will increase an additional one half of one
percent (.50%) effective immediately before the Event of Default.

        3.6.    DEDUCTIONS. Lender may deduct fees, Finance Charges and other
amounts due pursuant to this Agreement from any Advances made or Collections
received by Lender.

        3.7.    ACCOUNT COLLECTION SERVICES. All Borrower's Receivables are to
be paid to the same address/or party and Borrower and Lender must agree on such
address. If Lender collects all Receivables and there is not an Event of Default
or an event that with notice or lapse of time will be an Event of Default,
within three (3) days of receipt of those collections, Lender will give Borrower
the Receivables collections it receives for Receivables other than Financed
Receivables and/or amount in excess of the amount for which Lender has made an
Advance to Borrower, less any amount due to Lender, such as the Finance Charge,
the Collateral Handling Fee, the Facility Fee, other fees and expenses, or
otherwise. This Section 3.8 does not impose any affirmative duty on Lender to do
any act other than to turn over amounts. All Receivables and collections are
Collateral and if an Event of Default occurs, Lender need not remit collections
of Collateral and may apply them to the Obligations.

4.      REPAYMENT OF OBLIGATIONS.

        4.1.    REPAYMENT ON MATURITY. Borrower will repay each Advance on the
earliest of: (a) payment of the Financed Receivable in respect of which the
Advance was made, (b) the Financed Receivable becomes an Ineligible Receivable,
(c) when any Adjustment is made to the Financed Receivable (but only to the
extent of the Adjustment if the Financed Receivable is not otherwise an
Ineligible Receivable), or (d) the last day of the Facility Period (including
any early termination). Each payment will also include all accrued Finance
Charges on the Advance and all other amounts due hereunder.

        4.2.    REPAYMENT ON EVENT OF DEFAULT. When there is an Event of
Default, Borrower will, if Lender demands (or, in an Event of Default under
Section 9(B), immediately without notice or demand from Lender) repay all of the
Advances. The demand may, at Lender's option, include the Advance for each
Financed Receivable then outstanding and all accrued Finance Charges, attorneys
and professional fees, court costs and expenses, and any other Obligations.

5.      POWER OF ATTORNEY. Borrower irrevocably appoints Lender and its
successors and assigns it attorney-in-fact and authorizes Lender, regardless of
whether there has been an Event of Default, to:

                                (A)     following an Event of Default, sell,
                        assign, transfer, pledge, compromise, or discharge all
                        or any part of the Financed Receivables:

                                (B)     following an Event of Default, demand,
                        collect, sue, and give releases to any Account Debtor
                        for monies due and compromise, prosecute, or defend any
                        action, claim, case or proceeding about the Financed
                        Receivables, including filing a claim or voting a claim
                        in any bankruptcy case in Lender's or Borrower's name,
                        as Lender chooses:

                                (C)     following an Event of Default, prepare,
                        file and sign Borrower's name on any notice, claim,
                        assignment, demand, draft, or notice of or satisfaction
                        of lien or mechanics' lien or similar document;

                                (D)     notify all Account Debtors to pay Lender
                        directly;

                                (E)     receive, open, and dispose of mail
                        addressed to Borrower;


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                                (F)     endorse Borrower's name on check or
                        other instruments;

                                (G)     execute on Borrower's behalf any
                        instruments, documents, financing statements to perfect
                        Lender's interests in the Financed Receivables and
                        Collateral and do all acts and things necessary or
                        expedient, as determined solely and exclusively by the
                        Lender, to protect, preserve, and otherwise enforce the
                        Lender's rights and remedies under this Agreement, as
                        directed by the Lender;


6.      REPRESENTATIONS, WARRANTIES AND COVENANTS.

        6.1.    REPRESENTATIONS AND WARRANTIES. Borrower represents and warrants
for each Financed Receivable:

                                (A)     Borrower is the owner with legal right
                        to sell, transfer and assign it;

                                (B)     The correct amount is on the Invoice
                        Transmittal and is not disputed;

                                (C)     Payment is not contingent on any
                        obligation or contract and it has fulfilled all its
                        obligations as of the Invoice Transmittal date provided,
                        however, that some payments under Service Agreements may
                        be contingent upon Borrower providing services under the
                        terms of such Service Agreements;

                                (D)     It is based on an actual sale and
                        delivery of goods and/or services rendered, due to
                        Borrower, it is not past due or in default, has not been
                        previously sold, assigned, transferred, or pledged and
                        is free of any liens, security interests and
                        encumbrances provided, however, some Service Agreements
                        may be based on delivery of services in the future by
                        Borrower under terms of such Service Agreements;

                                (E)     There are no defenses, offsets,
                        counterclaims or agreements for which the Account Debtor
                        may claim any deduction or discount;

                                (F)     Borrower reasonably believes no Account
                        Debtor is insolvent or subject to any Insolvency
                        Proceedings;

                                (G)     Borrower has not filed or had filed
                        against it Insolvency Proceedings and does not
                        anticipate any filing;

                                (H)     Lender has the right to endorse and/ or
                        require Borrower to endorse all payments received on
                        Financed Receivables and all proceeds of Collateral; and

                                (I)     No representation, warranty or other
                        statement of Borrower in any certificate or written
                        statement given to Lender contains any untrue statement
                        of a material fact or omits to state a material fact
                        necessary to make the statement contained in the
                        certificates or statement not misleading.

        6.2.    ADDITIONAL REPRESENTATIONS AND WARRANTIES. Borrower represents
and warrants as follows:

                                (A)     Borrower is duly existing and in good
                        standing in its state of formation and qualified and
                        licensed to do business in, and in good standing in, any
                        state in which the conduct of its business or its
                        ownership of property requires that it be qualified. The


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                        execution, delivery and performance of this Agreement
                        has been duly authorized, and does not conflict with
                        Borrower's organizational documents or constitute an
                        Event of Default under any material agreement by which
                        Borrower is bound. Borrower is not in default under any
                        agreement to which or by which it is bound, the default
                        of which will have a material adverse effect on the
                        Borrower's business.

                                (B)     Borrower has good title to the
                        Collateral. All inventory is in all material respects of
                        good and marketable quality, free from material defects.

                                (C)     Borrower is not an "investment company"
                        or a company "controlled" by an "investment company"
                        under the Investment Company Act. Borrower is not
                        engaged as one of its important activities in extending
                        credit for margin stock (under Regulations T and U of
                        the Federal Reserve Board of Governors). Borrower has
                        complied with the Federal Fair Labor Standards Act.
                        Borrower has not violated any laws, ordinances or rules.
                        None of Borrower's properties or assets has been used by
                        Borrower, to the best of Borrower's knowledge, by
                        previous persons, in disposing, producing, storing,
                        treating, or transporting any hazardous substance other
                        than legally. Borrower has timely filed all required tax
                        returns and paid, or made adequate provision to pay, all
                        taxes. Borrower has obtained all consents, approvals and
                        authorizations of, made all declarations or filings
                        with, and given all notices to, all government
                        authorities that are necessary to continue its business
                        as currently conducted.

        6.3.    AFFIRMATIVE COVENANTS. Borrower will do all of the following:

                                (A)     Maintain its corporate existence and
                        good standing in its jurisdictions of incorporation and
                        maintain its qualification in each jurisdiction
                        necessary to Borrower's business or operations.

                                (B)     Give Lender at least ten (10) days'
                        prior written notice of changes to its name,
                        organization, chief executive office or location of
                        records.

                                (C)     Pay all its taxes including gross
                        payroll, withholding and sales taxes when due and will
                        deliver satisfactory evidence of payment if requested.

                                (D)     Provide a written report respecting any
                        Financed Receivable as part of the monthly accounting
                        required in Section 3.4 hereof (or as and when otherwise
                        directed by the Lender), if payment of any Financed
                        Receivable does not occur by its due date and include
                        the reasons for the delay.

                                (E)     Give Lender copies of all Forms 10-K,
                        10-Q and 8-K (or equivalents) within five (5) days of
                        filing with the Securities and Exchange Commission,
                        while any Financed Receivable is outstanding.

                                (F)     Execute any further instruments and take
                        further action as Lender reasonably requests to perfect
                        or continue Lender's security interest in the Collateral
                        or to effect the purposes of this Agreement.

                                (G)     Provide Lender with, as soon as
                        available, but no later than thirty (30) days following
                        each Reconciliation Period, a company prepared balance
                        sheet and income statement, prepared under GAAP,
                        consistently applied, covering Borrower's consolidated
                        operations during the period together with an aged
                        listing of Receivables


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                        (but such aged listing shall only be furnished while
                        there are Financed Receivables or upon Lender's
                        request). All of the foregoing shall be in form and
                        substance satisfactory to the Lender in its sole but
                        reasonable determination.

                                (H)     Within thirty (30) days after the last
                        day of each month and within ninety (90) days after the
                        last day of each fiscal year or as otherwise directed by
                        the Lender in its sole discretion, Borrower shall
                        deliver to Lender a Compliance Certificate signed by a
                        Responsible Officer in the form of EXHIBIT "B". The
                        Borrower shall provide the Lender with all other
                        financial information reasonably requested by the Lender
                        from time to time, including, without limitation,
                        periodic deferred revenue schedules. All of the
                        foregoing shall be in form and substance satisfactory to
                        the Lender.

                                (I)     Immediately notify, transfer and deliver
                        to Lender all collections Borrower receives for Financed
                        Receivables (and, as and when required hereunder, for
                        all Receivables).

                                (J)     The Borrower shall remit all Financed
                        Receivables cash payments and remittances to the Lender
                        at least weekly (at the close of business on each
                        Friday). Notwithstanding the foregoing, upon the
                        earliest to occur of: (a) March 31, 2001 or (b) the
                        occurrence of any Event of Default, or (c) written
                        notification to the Borrower provided by the Lender (in
                        its sole and exclusive discretion), the Borrower shall
                        direct each Account Debtor to make payments with respect
                        to all Receivables to a lockbox account established with
                        the Lender ("Lockbox").

                                (K)     Borrower will allow Lender to audit
                        Borrower's Collateral, including, but not limited to,
                        Borrower's Accounts and Receivables, at Borrower's
                        expense, no later than ninety (90) days after the
                        execution of this Agreement and annually thereafter.
                        Provided, however, if an Event of Default has occurred,
                        Lender may audit Borrower's Collateral, including, but
                        not limited to, Borrower's Accounts and Receivables at
                        Lender's sole and exclusive discretion and without
                        notification and authorization from Borrower.

                                (L)     Bank shall, upon Borrower's request,
                        issue up to Five Million Dollars ($5,000,000.00) in
                        unsecured letters of credit on behalf of Borrower,
                        provided that Borrower maintains at least Ten Million
                        Dollars ($10,000,000.00) in unrestricted cash balances
                        with the Lender at all times and is otherwise in
                        compliance with this Agreement. In the event that the
                        Borrower does not, at any time maintain at least Ten
                        Million Dollars ($10,000,000.00) in unrestricted cash
                        balances with the Lender and there are outstanding
                        unsecured letters of credit, Borrower shall have the
                        options of: (a) immediately cash securing all unsecured
                        letters of credit pursuant to terms and conditions
                        acceptable to Lender; or (b) as long as no Event of
                        Default has occurred and is continuing, treating all
                        outstanding unsecured letters of credit as an Advance
                        subject to the provisions of Section 2.2 hereof.

                                (M)     Borrower shall maintain as of the last
                        day of each month unless otherwise noted:

                (1) Quick Ratio. A ratio of Quick Assets to Current Liabilities
        of at least .90 to 1.0 through June 30, 2001; and ratio of Quick Assets
        to Current Liabilities of at least 1.0 to 1.0 thereafter.

                (2) Maximum Net Loss/Minimum Net Profit. (i) quarterly Net
        Losses not to exceed (A) Nineteen Million Five Hundred Thousand Dollars
        (19,500,000.00) for the quarter ending December 31, 2000,


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<PAGE>   9

        (B) Seven Million Two Hundred Fifty Thousand Dollars ($7,250,000.00) for
        the quarter ending March 31, 2001, (C) Three Million Five Hundred
        Thousand Dollars ($3,500,000.00) for the quarter ending June 30, 2001;
        (D) One Million Two Hundred Fifty Thousand Dollars ($1,250,000.00) for
        the quarter ending September 30, 2001; (ii) quarterly Net Profit of at
        least One Million Dollars ($1,000,000.00) for the quarter ending
        December 31, 2001; and (iii) a quarterly Net Profit of One Dollar
        ($1.00), for each quarter thereafter.

        6.4.    NEGATIVE COVENANTS. Borrower will not do any of the following,
except as permitted in the Loan Agreement, without Lender's prior written
consent:

                                (A)     Except for dispositions of Borrower's
                        inventory in the ordinary course of business, assign,
                        transfer, sell or grant, or permit any lien or security
                        interest in the Collateral.

                                (B)     Except for the disposition of Obsolete
                        Equipment in the ordinary course of business, convey,
                        sell, lease, transfer or otherwise dispose of the
                        Collateral.

                                (C)     Create, incur, assume, or be liable for
                        any indebtedness (with the exception of trade payables
                        incurred in the normal course of business).

                                (D)     Become an "investment company" or a
                        company controlled by an "investment company," under the
                        Investment Company Act of 1940 or undertake as one of
                        its important activities extending credit to purchase or
                        carry margin stock, or use the proceeds of any Advance
                        for that purpose; fail to meet the minimum funding
                        requirements of ERISA, permit a Reportable Event or
                        Prohibited Transaction, as defined in ERISA, to occur;
                        fail to comply with the Federal Fair Labor Standards
                        Act, or violated any other law or regulation, or permit
                        any of its subsidiaries to do so.

7.      ADJUSTMENTS. If any Account Debtor asserts a discount, allowance,
return, offset, defense, warranty claim, or the like (an "Adjustment") or if
Borrower breaches any of the representations, warranties or covenants set forth
in Section 6, Borrower will promptly advise Lender. Borrower will resell any
rejected, returned, or recovered personal property for Lender, at Borrower's
expense, and pay proceeds to Lender. Lender owns the Financed Receivables and
until receipt of payment, has the right to take possession of any rejected,
returned, or recovered personal property.

8.      SECURITY INTEREST. Borrower grants to Lender a continuing security
interest in all presently and later acquired Collateral. Any security interest
will be a first priority security interest in the Collateral.

9.      EVENTS OF DEFAULT. Any one or more of the following is an Event of
Default.

                                (A)     Borrower fails to pay any amount owed to
                        Lender when due, including any obligations under a
                        certain Loan and Security Agreement of even date between
                        the Borrower and Lender;

                                (B)     Borrower files or has filed against it
                        any Insolvency Proceedings or any assignment for the
                        benefit of creditors, or appointment of a receiver or
                        custodian for any of its assets;

                                (C)     Borrower becomes insolvent or is
                        generally not paying its debts as they become due or is
                        left with unreasonably small capital;


                                      -9-
<PAGE>   10

                                (D)     (i) Any material portion of Borrower's
                        assets or any Financed Receivable is attached, seized,
                        levied on, or comes into possession of a trustee or
                        receiver and the attachment, seizure or levy is not
                        removed in ten (10) days; (ii) the service of process
                        upon the Borrower seeking to attach, by trustee or
                        similar process any funds of the Borrower on deposit
                        with the Lender; (iii) Borrower is enjoined, restrained,
                        or prevented by court order from conducting any part of
                        its business; (iv) a judgment or other claim becomes a
                        Lien on a material portion of Borrower's assets or any
                        Financed Receivable; or (v) a notice of lien, levy, or
                        assessment is filed against a material portion of
                        Borrower's assets or any Financed Receivable by any
                        government agency and not paid within ten (10) days
                        after Borrower receives notice. With the exception of
                        subsection (ii) above, these are not Events of Default
                        if stayed or if a bond is posted pending contest by
                        Borrowers (but no Advances shall be made during the cure
                        period);

                                (E)     Borrower breaches any covenant,
                        agreement, warranty, or representation and does not cure
                        it to Lender's satisfaction within ten (10) days; but a
                        breach that cannot be cured it is an immediate Event of
                        Default;

                                (F)     Borrower defaults under any agreement to
                        which Borrower is a party with a third party or parties
                        resulting in a right by such third party or parties,
                        whether or not exercised, to accelerate the maturity of
                        any Indebtedness in an amount in excess of Two Hundred
                        Thousand Dollars ($200,000.00) or that could result in a
                        material adverse change in Borrower's financial
                        condition or the Lender's perfection or priority in the
                        Financed Receivables or the Collateral;

                                (G)     An event of default occurs under any
                        guaranty of the Obligations or any material provision of
                        any guaranty is not valid or enforceable or a guaranty
                        is repudiated or terminated;

                                (H)     A material default or Event of Default
                        occurs under any agreement between Borrower and any
                        creditor of Borrower that signed a subordination
                        agreement with Lender;

                                (I)     Any creditor that has signed a
                        subordination agreement with Lender breaches any terms
                        of the subordination agreement; or

                                (J)     Any of the following occurs: (i) A
                        material impairment in the perfection or priority of the
                        Lender's security interest in the Collateral; (ii) a
                        material adverse change in the business, operations, or
                        conditions (financial or otherwise) of the Borrower; or
                        (iii) a material impairment of the prospect of repayment
                        of any portion of the Advances.

10.     REMEDIES.

        10.1.   REMEDIES UPON DEFAULT. When an Event of Default occurs, (1)
Lender may stop financing Receivables or extending credit to Borrower; (2) at
Lender's option and on demand, all or a portion of the Obligations (or, for to
an Event of Default described in Section 9(B), automatically and without demand)
are due and payable in full; (3) the Lender may apply to the Obligations any (i)
balances and deposits of Borrower it holds, or (ii) any amount held by Lender
owing to or for the credit or the account of Borrower; and (4) Lender may
exercise all rights and remedies under this Agreement and the law, including
those of a secured party under the Code, power of attorney rights in Section 5
for the Collateral, and the right to collect, dispose of, sell, lease, use, and
realize upon all Financed Receivables and Collateral in any commercially
reasonable manner. Borrower agrees that


                                      -10-
<PAGE>   11

any notice of sale required to be given to Borrower is deemed given if at least
five (5) days before the sale may be held.

        10.2.   DEMAND WAIVER. Except as expressly provided in this Agreement,
the Borrower waives demand, notice of default or dishonor, notice of payment and
nonpayment, notice of any default, nonpayment at maturity, release, compromise,
settlement, extension, or renewal of accounts, documents, instruments, chattel
paper, and guaranties held by Lender on which Borrower is liable.

        10.3.   DEFAULT RATE. While any Event of Default exists, all Advances
hereunder shall bear interest at the Applicable Rate plus five percent (5%) per
annum until the earliest of (a) payment of all Obligations in good funds or (b)
the Event of Default is cured in the sole and exclusive determination of the
Lender, or (c) entry of a final judgment when the principal amount of any money
judgment will accrue interest at the highest rate allowed by law.

11.     FEES, COSTS AND EXPENSES. The Borrower will pay on demand all fees,
costs and expenses (including attorneys' and professionals fees with costs and
expenses) that Lender incurs from: (a) preparing, negotiating, administering,
and enforcing this Agreement or related agreement, including any amendments,
waivers or consents, (b) any litigation or dispute relating to the Financed
Receivables, the Collateral, this Agreement or any other agreement, (c)
enforcing any rights against Borrower or any guarantor, or any Account Debtor,
(d) protecting or enforcing its interest in the Financed Receivables or other
Collateral, (e) collecting the Financed Receivables and the Obligations, and (f)
any bankruptcy case or insolvency proceeding involving Borrower, any Financed
Receivable, the Collateral, any Account Debtor, or any Guarantor.

12.     CHOICE OF LAW, VENUE AND JURY TRIAL WAIVER. This Agreement shall be
construed, governed, and enforced pursuant to the laws (without regard to
conflict of law principles) of The Commonwealth of Massachusetts. Borrower and
Lender each submits to the exclusive jurisdiction of the State and Federal
courts in Suffolk County, Massachusetts.

BORROWER AND LENDER EACH WAIVE THEIR RIGHT TO A JURY TRIAL OF ANY CLAIM OR CAUSE
OF ACTION ARISING OUT OF OR BASED UPON THIS AGREEMENT OR ANY CONTEMPLATED
TRANSACTION, INCLUDING CONTRACT, TORT, BREACH OF DUTY AND ALL OTHER CLAIMS. THIS
WAIVER IS A MATERIAL INDUCEMENT FOR BOTH PARTIES TO ENTER INTO THIS AGREEMENT.
EACH PARTY HAS REVIEWED THIS WAIVER WITH ITS COUNSEL.

13.     NOTICES.

        Notices and other communications provided for herein shall be in writing
and shall be delivered by hand or overnight courier service, mailed by certified
or registered mail or sent by facsimile, as follows:

        If to any Borrower:  Visual Networks, Inc.
                             2092 Gaither Road
                             Rockville, Maryland 20850
                             Attn: Hank Deily, Director, Treasury Operations
                             FAX: (301) 296-2303

        with a copy to:      Piper Marbury Rudnick & Wolfe LLP
                             1850 Centennial Park Drive
                             Suite 610
                             Reston, Virginia 20191
                             Attention:  Nancy Spangler, Esq.
                             Telephone:  (703) 391-7100
                             Facsimile:  (703) 390-5299


                                      -11-
<PAGE>   12

        If to Lender:        Silicon Valley Bank
                             11600 Sunrise Valley Drive, Suite 400
                             Reston, Virginia 20191
                             Attn: Michael Selfridge, Senior Vice-President
                             FAX:  (703) 648-3034

        with a copy to:      Riemer & Braunstein LLP
                             Three Center Plaza
                             Boston, Massachusetts 02108
                             Attn: David A. Ephraim, Esquire
                             FAX: (617) 880-3456

        All notices and other communications given to any party hereto in
accordance with the provisions of this Agreement shall be deemed to have been
given (i) two (2) business days after being sent by registered or certified
mail, return receipt requested, postage prepaid, or (ii) one (1) business day
after being sent via a reputable nationwide overnight courier service
guaranteeing next business day deliver, or (iii) on the date on which it is sent
by facsimile transmission with acknowledgment of receipt at the number to which
it is required to be sent in each case to the intended recipient as set forth
above.

14.     GENERAL PROVISIONS.

        14.1.   BORROWER LIABILITY. Any Borrower may, acting singly, request
Advances hereunder. Each Borrower hereby appoints the other as agent for the
other for all purposes hereunder, including with respect to requesting Advances
hereunder. Each Borrower hereunder shall be obligated to repay all Advances made
hereunder, regardless of which Borrower actually receives said Advance, as if
each Borrower hereunder directly received all Advances. Each Borrower
acknowledges that, to the extent any other Borrower has or may have certain
rights of subrogation or reimbursement against the other for claims arising out
of this Agreement, that those rights are hereby waived.

        14.2.   SUBROGATION AND SIMILAR RIGHTS. Notwithstanding any other
provision of this Agreement or other related document, each Borrower irrevocably
waives all rights that it may have at law or in equity (including, without
limitation, any law subrogating the Borrower to the rights of Lender under the
Loan Documents) to seek contribution, indemnification or any other form of
reimbursement from any other Borrower, or any other Person now or hereafter
primarily or secondarily liable for any of the Obligations, for any payment made
by the Borrower with respect to the Obligations in connection with the Loan
Documents or otherwise and all rights that it might have to benefit from, or to
participate in, any security for the Obligations as a result of any payment made
by the Borrower with respect to the Obligations in connection with the Loan
documents or otherwise. Any agreement providing for indemnification,
reimbursement or any other arrangement prohibited under this Section shall be
null and void. If any payment is made to a Borrower in contravention of this
Section, such Borrower shall hold such payment in trust for Lender and such
payment shall be promptly delivered to Lender for application to the
Obligations, whether matured or unmatured.

        14.3.   SUCCESSORS AND ASSIGNS. This Agreement binds and is for the
benefit of successors and permitted assigns of each party. Unless pursuant to a
merger or consolidation permitted under Section 7.3 of the Loan and Security
Agreement, Borrower may not assign this Agreement or any rights under it without
Lender's prior written consent which may be granted or withheld in Lender's
discretion. Lender may, without the consent of or notice to Borrower, sell,
transfer, or grant participation in any part of Lender's obligations, rights or
benefits under this Agreement.


                                      -12-
<PAGE>   13

        14.4.   RIGHT OF SET-OFF. Borrower and any guarantor hereby grant to
Lender, a lien, security interest and right of setoff as security for all
Obligations (up to the amount of such Obligations) to Lender, whether now
existing or hereafter arising upon and against all deposits, credits, collateral
and property, now or hereafter in the possession, custody, safekeeping or
control of Lender or any entity under the control of Silicon Valley Bank or in
transit to any of them. At any time after the occurrence and during the
continuance of an Event of Default, without demand or notice, Lender may set off
the same or any part thereof and apply the same to any liability or obligation
of Borrower and any guarantor even though unmatured and regardless of the
adequacy of any other collateral securing the loan. ANY AND ALL RIGHTS TO
REQUIRE LENDER TO EXERCISE ITS RIGHTS OR REMEDIES WITH RESPECT TO ANY OTHER
COLLATERAL WHICH SECURES THE LOAN, PRIOR TO EXERCISING ITS RIGHT OF SETOFF WITH
RESPECT TO SUCH DEPOSITS, CREDITS OR OTHER PROPERTY OF THE BORROWER OR ANY
GUARANTOR, ARE HEREBY KNOWINGLY, VOLUNTARILY AND IRREVOCABLY WAIVED.

        14.5.   INDEMNIFICATION. Borrower will indemnify, defend and hold
harmless Lender and its officers, employees, and agents against: (a)
obligations, demands, claims, and liabilities asserted by any other party in
connection with the transactions contemplated by this Agreement; and (b) losses
or expenses incurred, or paid by Lender from or consequential to transactions
between Lender and Borrower (including reasonable attorneys fees and expenses),
except for losses caused by Lender's gross negligence or willful misconduct.

        14.6.   TIME OF ESSENCE. Time is of the essence for performance of all
obligations in this Agreement.

        14.7.   SEVERABILITY OF PROVISION. Each provision of this Agreement is
severable from every other provision in determining the enforceability of any
provision.

        14.8.   AMENDMENTS IN WRITING, INTEGRATION. All amendments to this
Agreement must be in writing. This Agreement is the entire agreement about this
subject matter and supersedes prior negotiations or agreements.

        14.9.   COUNTERPARTS. This Agreement may be executed in any number of
counterparts and by different parties on separate counterparts and when executed
and delivered are one Agreement.

        14.10.  SURVIVAL. All covenants, representations and warranties made in
this Agreement continue in force while any Financed Receivable amount remains
outstanding. Borrower's indemnification obligations survive until all statutes
of limitations for actions that may be brought against Lender have run.

        14.11.  CONFIDENTIALITY. Lender will use the same degree of care
handling Borrower's confidential information that it uses for its own
confidential information, but may disclose information; (i) to its subsidiaries
or affiliates in connection with their business with Borrower, (ii) to
prospective transferees or purchasers of any interest in the Agreement, (iii) as
required by law, regulation, subpoena, or other order, (iv) as required in
connection with an examination or audit and (v) as reasonably required to
exercise the remedies under this Agreement. Confidential information does not
include information that is either: (a) in the public domain or in Lender's
possession when disclosed, or becomes part of the public domain after disclosure
to Lender; or (b) disclosed to Lender by a third party, if Lender does not
reasonably know that the third party is prohibited from disclosing the
information. The obligation set forth in this Section 14.11 shall survive the
termination of this Agreement for a period of three (3) years from the
termination of the Facility Period.

        14.12.  OTHER AGREEMENTS. This Agreement may not adversely affect
Lender's rights under any other document or agreement. If there is a conflict
between this Agreement and any agreement between Borrower and Lender, Lender may
determine in its sole discretion which provision applies. Borrower acknowledges
that any security agreements, liens and/or security interests securing payment
of Borrower's Obligations also secure Borrower's Obligations under this
Agreement and are not adversely affected by this Agreement. Additionally, (a)
any Collateral under other agreements or documents between Borrower and Lender
secures Borrower's


                                      -13-
<PAGE>   14

Obligations under this Agreement and (b) a default by Borrower under this
Agreement is a default under agreements between Borrower and Lender.

BORROWER:

VISUAL NETWORKS, INC.

By:     /s/ Peter J. Minihane
        ------------------------
        Peter J. Minihane

Title:  Chief Financial Officer
        ------------------------


VISUAL NETWORKS OPERATIONS, INC.

By:     /s/ Peter J. Minihane
        ------------------------
        Peter J. Minihane

Title:  Treasurer
        ------------------------


VISUAL NETWORKS INVESTMENTS, INC.

By:     /s/ Peter J. Minihane
        ------------------------
        Peter J. Minihane

Title:  Treasurer


VISUAL NETWORKS TECHNOLOGIES, INC.

By:     /s/ Peter J. Minihane
        ------------------------
        Peter J. Minihane

Title:  Treasurer
        ------------------------

VISUAL NETWORKS OF TEXAS, L.P.
by Visual Networks Texas Operations, Inc., its
General Partner

By:     /s/ Peter J. Minihane
        ------------------------
        Peter J. Minihane

Title:  Treasurer
        ------------------------



                                      -14-
<PAGE>   15

VISUAL NETWORKS INSURANCE, INC.

By:     /s/ Peter J. Minihane
        ------------------------
        Peter J. Minihane

Title:  Treasurer
        ------------------------



INVERSE NETWORK TECHNOLOGY

By:     /s/ Peter J. Minihane
        ------------------------
        Peter J. Minihane

Title:  President
        ------------------------


AVESTA TECHNOLOGIES, INC.

By:     /s/ Peter J. Minihane
        ------------------------
        Peter J. Minihane

Title:  President
        ------------------------


LENDER:

SILICON VALLEY BANK


By  /s/ David J. Reich
  ------------------------------------------

Title   SVP
      --------------------------------------
         (Signed in Santa Clara, California)



SILICON VALLEY BANK, doing business as
"SILICON VALLEY EAST"


By  /s/ David J. Reich
  ------------------------------------------

Title   SVP
      --------------------------------------


616741.6 (56120/293)


                                      -15-
<PAGE>   16


                                    EXHIBIT A


        The Collateral consists of all of Borrower's right, title and interest
in and to the following:

        All goods, equipment, inventory, contract rights, trademarks,
servicemarks, trade styles, trade names, patents, patent applications, leases,
license agreements, franchise agreements, general intangibles, accounts,
documents, instruments, chattel paper, cash, deposit accounts, fixtures, letters
of credit, investment property, and financial assets, whether now owned or
hereafter acquired, wherever located; and

        Any copyright rights, copyright applications, copyright registrations
and like protections in each work of authorship and derivative work, whether
published or unpublished, now owned or later acquired; any patents, trademarks,
service marks and applications therefor; any trade secret rights, including any
rights to unpatented inventions, know-how, operating manuals, license rights and
agreements and confidential information, now owned or hereafter acquired; or any
claims for damages by way of any past, present and future infringement of any of
the foregoing; and

        All Borrower's Books relating to the foregoing and any and all claims,
rights and interests in any of the above and all substitutions for, additions,
attachments, accessories, accessions and improvements to and replacements,
products, proceeds and insurance proceeds of any or all of the foregoing.


                                      -16-
<PAGE>   17


                                   EXHIBIT "B"


                               SILICON VALLEY BANK


                               Invoice Transmittal

I, as a Responsible Officer of VISUAL NETWORKS, INC., a Delaware corporation,
("Borrower") certify under the Accounts Receivable Financing Agreement (the
"Agreement") between Borrower and Lender ("Lender") as follows.

BORROWER REPRESENTS AND WARRANTS FOR EACH FINANCED RECEIVABLE:

        To Borrower's knowledge, it is the owner with legal right to sell,
transfer and assign it;

        To Borrower's knowledge, the correct amount is on the Invoice
Transmittal and is not disputed;

        Payment is not contingent on any obligation or contract and it has
fulfilled all its obligations as of the Invoice Transmittal date;

        It is based on an actual sale and delivery of goods and/or services
rendered, due to Borrower, it is not past due or in default, has not been
previously sold, assigned, transferred, or pledged and is free of any liens,
security interests and encumbrances;

        To Borrower's knowledge, there are no defenses, offsets, counterclaims
or agreements for which the Account Debtor may claim any deduction or discount;

        Borrower reasonably believes no Account Debtor is insolvent or subject
to any Insolvency Proceedings;

        Borrower has not filed or had filed against it proceedings and does not
anticipate any filing;

        Lender has the right to endorse and/ or require Borrower to endorse all
payments received on Financed Receivables and all proceeds of Collateral.

        No representation, warranty or other statement of Borrower in any
certificate or written statement given to Lender contains any untrue statement
of a material fact or omits to state a material fact necessary to make the
statement contained in the certificates or statement not misleading.

        ADDITIONALLY, BORROWER REPRESENTS AND WARRANTS AS FOLLOWS:

        Borrower is duly existing and in good standing in its state of formation
and qualified and licensed to do business in, and in good standing in, any state
in which the conduct of its business or its ownership of property requires that
it be qualified. The execution, delivery and performance of this Agreement has
been duly authorized, and do not conflict with Borrower's formations documents,
nor constitute an Event of Default under any material agreement by which
Borrower is bound. Borrower is not in default under any material agreement to
which or by which it is bound.

        Borrower has good title to the Collateral. All inventory is in all
material respects of good and marketable quality, free from material defects.


                                      -17-
<PAGE>   18

        Borrower is not an "investment company" or a company "controlled" by an
"investment company" under the Investment Company Act. Borrower is not engaged
as one of its important activities in extending credit for margin stock (under
Regulations G, T and U of the Federal Reserve Board of Governors). Borrower has
complied with the Federal Fair Labor Standards Act. None of Borrower's
properties or assets has been used by Borrower, to the best of Borrower's
knowledge, by previous persons, in disposing, producing, storing, treating, or
transporting any hazardous substance other than legally. Borrower has timely
filed all required tax returns and paid, or made adequate provision to pay, all
taxes. Borrower has obtained all consents, approvals and authorizations of, made
all declarations or filings with, and given all notices to, all government
authorities that are necessary to continue its business as currently conducted.

        All representations and warranties in the Agreement are true and correct
in all material respects on this date.

Sincerely,


----------------------------------
SIGNATURE


----------------------------------
TITLE


----------------------------------
DATE


                                      -18-
<PAGE>   19


                                    EXHIBIT C
                             COMPLIANCE CERTIFICATE

TO:     SILICON VALLEY BANK
FROM: VISUAL NETWORKS, INC.

        The undersigned Responsible Officer of VISUAL NETWORKS, INC. certifies
that under the terms and conditions of the Accounts Receivable Financing
Agreement between Borrower and Lender (the "Agreement"), (i) Borrower is in
complete compliance for the period ending _______________ with all required
covenants except as noted below and (ii) all representations and warranties in
the Agreement are true and correct in all material respects on this date.
Attached are the required documents supporting the certification. The Officer
certifies that these are prepared in accordance with Generally Accepted
Accounting Principles (GAAP) consistently applied from one period to the next
except as explained in an accompanying letter or footnotes. The Officer
acknowledges that no borrowings may be requested at any time or date of
determination that Borrower is not in compliance with any of the terms of the
Agreement, and that compliance is determined not just at the date this
certificate is delivered.

        PLEASE INDICATE COMPLIANCE STATUS BY CIRCLING YES/NO UNDER "COMPLIES"
COLUMN.

<TABLE>
<S>                                             <C>
        REPORTING COVENANT                         REQUIRED                           COMPLIES
        ------------------                         --------                           --------

        Monthly financial statements with CC       Monthly within 30 days             Yes   No
        Annual (CPA Audited)  with CC              FYE within 90 days                 Yes   No

        FINANCIAL COVENANT                         REQUIRED                 ACTUAL         COMPLIES
        ------------------                         --------                 ------         --------
        Maintain on a Monthly Basis:

        Minimum Quick Ratio (monthly)              .90:1.0 through 6/30/01  _____:1.0      Yes   No
                                                   1.0:1.0 thereafter       _____:1.0      Yes   No

        Maximum Net Loss/Profit (quarterly):       ($*    )                 ($_________)   Yes   No
</TABLE>

        *(i) ($19,500,000.00) for the quarter ending 12/31/00;
        *(ii) ($7,250,000.00) for the quarter ending 3/31/01;
        *(iii) ($3,500,000.00) for the quarter ending 6/30/01;
        *(iv) ($1,250,000.00) for the quarter ending 9/30/01;
        *(v) $1,000,000.00 for the quarter ending 12/31/01;
        *(vi) a quarterly net profit of $1.00 thereafter.



COMMENTS REGARDING EXCEPTIONS:  See Attached, if any.

Sincerely,


-----------------------------
SIGNATURE

-----------------------------
TITLE

-----------------------------
DATE



---------------------------------------
             LENDER USE ONLY
Received by:
            -------------------------
                  AUTHORIZED SIGNER

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


Verified:
         ----------------------------
                  AUTHORIZED SIGNER


Date:
        -----------------------------
Compliance Status:       Yes    No
3
---------------------------------------

                                      -19-
<PAGE>   20



                            AMENDED LOCKBOX AGREEMENT


VISUAL NETWORKS, INC., a Delaware corporation ("Borrower") shall hold all
payments on, and proceeds of, Receivables in trust for Lender ("Silicon"), and
Borrower shall immediately deliver all such payments and proceeds to Silicon in
their original form, duly endorsed in blank, to be applied to the Obligations in
such order as Silicon shall determine.

Borrower hereby agrees to accept a change in the disposition of its lockbox
#___________ proceeds from the current account #______________ to the Silicon
Cash Collateral Account #_______________ beginning immediately. We understand
that Silicon may, in its discretion, require that all proceeds of Collateral be
deposited by Borrower into a lockbox account, or such other "blocked account" as
Silicon may specify, pursuant to a blocked account agreement in such form as
Silicon may specify. Silicon or its designee may, at any time, notify Account
Debtors that Receivables have been assigned to Silicon.

DATED:

AGREED TO AND ACKNOWLEDGED BY:

Borrower:

        VISUAL NETWORKS, INC.

        By
          --------------------------------------
          President or Vice President

        By
          --------------------------------------
          Secretary or Ass't Secretary

Lender:

        SILICON VALLEY BANK

        By
          --------------------------------------

        Title
             -----------------------------------
             (Signed in Santa Clara, California)

        SILICON VALLEY BANK, doing
        business as "SILICON VALLEY EAST"

        By
          --------------------------------------

        Title
             -----------------------------------

616741.6 (56120/293)


                                      -20-