Exhibit 10.25.3

     THIRD LOAN MODIFICATION TO THE ACCOUNTS RECEIVABLE FINANCING AGREEMENT

    This Second Loan Modification Agreement to the Accounts Receivable
Financing Agreement (this "Loan Modification Agreement') is entered into as of
February 28, 2002, by and 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" ("Bank") (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" or
"Borrowers").

1. DESCRIPTION OF EXISTING INDEBTEDNESS AND OBLIGATIONS. Among other
indebtedness and obligations which may be owing by Borrower to Bank, Borrower is
indebted to Bank pursuant to a loan arrangement dated as of February 28, 2001,
evidenced by, among other documents, (i) a certain Accounts Receivable Financing
Agreement dated as of February 28, 2001, between Borrower and Bank, as amended
by a certain First Loan Modification to the Accounts Receivable Financing
Agreement dated as of May 24, 2001, as further amended by a certain Second Loan
Modification to the Accounts Receivable Financing Agreement dated as of December
20, 2001 (as may be amended from time to time, the "Financing Agreement") and,
(ii) a certain Loan and Security Agreement dated as of February 28, 2001,
between Borrower and Bank, as amended by a certain First Loan Modification
Agreement dated as of May 24, 2001, as further amended by a certain Second Loan
Modification to the Loan and Security Agreement dated as of December 20, 2001
(as may be amended from time to time, the "Loan Agreement"). The Financing
Agreement established: (i) an accounts receivable line of credit in favor of
Borrower in the maximum principal amount of Ten Million Dollars ($10,000,000.00)
(the "Accounts Receivable Line"). Capitalized terms used but not otherwise
defined herein shall have the same meaning as in the Loan Agreement.

Hereinafter, all indebtedness and obligations owing by Borrower to Bank shall be
referred to as the "Obligations".

2.  DESCRIPTION OF COLLATERAL.  Repayment of the  Obligations is secured by
the Collateral as described in the Financing  Agreement (together with any other
collateral security granted to Bank, the "Security Documents").

Hereinafter, the Security Documents, together with all other documents
evidencing or securing the Obligations shall be referred to as the "Existing
Loan Documents".

3.  DESCRIPTION OF CHANGE IN TERMS.

A.  Modifications to Financing Agreement.


1.  The  Financing  Agreement  shall be amended by deleting  the  following,
definition appearing as in Section 1 thereof, in its entirety:

     "Facility Period" is the period beginning on this date and continuing until
February 28, 2002,  unless the period is terminated sooner by Lender with notice
to Borrower or by Borrower pursuant to the terms of this Agreement."

    and inserting in lieu thereof the following:

    "Facility Period" is the period beginning on this date and continuing until
April 29, 2002,  unless the period is terminated sooner by Lender with notice to
Borrower or by Borrower pursuant to the terms of this Agreement."


4. RATIFICATION OF INTELLECTUAL PROPERTY SECURITY AGREEMENT. Borrower hereby
ratifies, confirms and reaffirms, all and singular, the terms and conditions of
a certain Intellectual Property Security Agreement dated as of February 28,
2001, between Borrower and Bank, and acknowledges, confirms and agrees that said
Intellectual Property Security Agreement (including all Exhibits attached
thereto) shall remain in full force and effect and contain an accurate and
complete listing of all Intellectual Property Collateral as defined in said
Intellectual Property Security Agreement.

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5. ADDITIONAL COVENANTS: RATIFICATION OF PERFECTION CERTIFICATE. Borrower shall
not, without providing the Bank with thirty (30) days prior written notice: (i)
relocate its principal executive office or add any new offices or business
locations or keep any Collateral in any additional locations, or (ii) change its
state of formation, or (iii) change its organizational structure, (iv) change
its legal name, or (v) change any organizational number (if any) assigned by its
state of formation. Borrower hereby ratifies, confirms and reaffirms, all and
singular, the terms and disclosures contained in certain Perfection Certificates
dated as of February 28, 2001, between Borrower and Bank, and acknowledges,
confirms and agrees the disclosures and information above Borrower provided to
Bank in the Perfection Certificates have not changed, as of the date hereof.

6.  AUTHORIZATION TO FILE. Borrower hereby authorizes Bank to file financing
statements without notice to Borrower,  with all appropriate  jurisdictions,  as
Bank deems  appropriate,  in order to further perfect or protect Bank's interest
in the Collateral.

7. CONCERNING REVISED ARTICLE 9 OF THE UNIFORM COMMERCIAL CODE. The Borrower
affirms and reaffirms that notwithstanding the terms of the Security Documents
to the contrary, (i) that the definition of "Code", "UCC" or "Uniform Commercial
Code" as set forth in the Security Documents shall be deemed to mean and refer
to "the Uniform Commercial Code as adopted by The Commonwealth of Massachusetts
(presently, Mass. Gen. Laws. Ch. 106), may be amended and in effect from time to
time and (ii) the Collateral is all assets of the Borrower. In connection
therewith, the Collateral shall include, without limitation, the following
categories of assets as defined in the Code: goods (including inventory,
equipment and any accessions thereto), instruments (including promissory notes),
documents, accounts (including health-care-insurance receivables, and license
fees), chattel paper (whether tangible or electronic), deposit accounts,
letter-of-credit rights (whether or not the letter of credit is evidenced by a
writing), commercial tort claims, securities and all other investment property,
general intangibles (including payment intangibles and software), supporting
obligations and any and all proceeds of any thereof, wherever located, whether
now owned or hereafter acquired.

8.  CONSISTENT  CHANGES.  The Existing Loan  Documents  are hereby  amended
wherever necessary to reflect the changes described above.

9.  RATIFICATION OF LOAN DOCUMENTS.  Borrower hereby ratifies, confirms, and
reaffirms all terms and conditions of all security or other  collateral  granted
to the Bank,  and  confirms  that the  indebtedness  secured  thereby  includes,
without limitation, the Obligations.


10. NO DEFENSES OF BORROWER.  Borrower agrees that, as of this date, it has
no defenses against the obligations to pay any amounts under the Obligations.

11. CONTINUING VALIDITY. Borrower understands and agrees that in modifying the
existing Obligations, Bank is relying upon Borrower's representations,
warranties, and agreements, as set forth in the Existing Loan Documents. Except
as expressly modified pursuant to this Loan Modification Agreement, the terms of
the Existing Loan Documents remain unchanged and in full force and effect.
Bank's agreement to modifications to the existing Obligations pursuant to this
Loan Modification Agreement in no way shall obligate Bank to make any future
modifications to the Obligations. Nothing in this Loan Modification Agreement
shall constitute a satisfaction of the Obligations. It is the intention of Bank
and Borrower to retain as liable parties all makers of Existing Loan Documents,
unless the party is expressly released by Bank in writing. No maker will be
released by virtue of this Loan Modification Agreement.

12. RIGHT OF SET-OFF. In consideration of Bank's agreement to enter into this
Loan Modification Agreement, Borrower and any guarantor hereby reaffirm and
hereby grant to Bank, a lien, security interest and right of setoff as security
for all Obligations to Bank, 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 Bank 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, Bank 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 BANK TO EXERCISE ITS RIGHTS OR REMEDIES WITH RESPECT
TO ANY OTHER COLLATERAL WHICH SECURES THE OBLIGATIONS, 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.

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13. JURISDICTION/VENUE. Borrower accepts for itself and in connection with its
properties, unconditionally, the non-exclusive jurisdiction of any state or
federal court of competent jurisdiction in the Commonwealth of Massachusetts in
any action, suit, or proceeding of any kind against it which arises out of or by
reason of this Loan Modification Agreement; provided, however, that if for any
reason Bank cannot avail itself of the courts of the Commonwealth of
Massachusetts, then venue shall lie in Santa Clara County, California.

14. COUNTERSIGNATURE. This Loan Modification Agreement shall become effective
only when it shall have been executed by Borrower and Bank (provided, however,
in no event shall this Loan Modification Agreement become effective until signed
by an officer of Bank in California).


    This Loan Modification Agreement is executed as a sealed instrument
under the laws of the Commonwealth of Massachusetts as of the date first written
above.


BORROWERS:                                BANK:

VISUAL NETWORKS, INC.                     SILICON VALLEY BANK, doing business as
                                          SILICON VALLEY EAST

By       /s/ Richard H. Deily             By:       /s/ Steven J. DiPasquale

Title    Director, Treasury Operations    Name:    Steven J. DiPasquale

                                          Title:   Vice President
VISUAL NETWORKS OPERATIONS, INC.


By       /s/ Richard H. Deily

Title    Director, Treasury Operations


VISUAL NETWORKS INVESTMENTS, INC.

By       /s/ Richard H. Deily

Title    Director, Treasury Operations


VISUAL NETWORKS TECHNOLOGIES, INC.

By       /s/ Richard H. Deily

Title    Director, Treasury Operations


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

By       /s/ Richard H. Deily

Title    Director, Treasury Operations


VISUAL NETWORKS INSURANCE, INC.

By       /s/ Richard H. Deily

Title    Director, Treasury Operations


INVERSE NETWORK TECHNOLOGY

By       /s/ Richard H. Deily

Title    Director, Treasury Operations


AVESTA TECHNOLOGIES, INC.

By       /s/ Richard H. Deily

Title    Director, Treasury Operations