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                                                                     EXHIBIT 3.1

                              AMENDED AND RESTATED
                          CERTIFICATE OF INCORPORATION
                                       OF
                             VISUAL NETWORKS, INC.

                            Pursuant to Section 242
                         Of the Corporation Law of the
                               State of Delaware

                  Visual Networks, Inc. (hereinafter called the "Corporation"),
organized and existing under and by virtue of the General Corporation Law of
the State of Delaware, does hereby certify as follows:

                  The date of incorporation of the Corporation is December 13,
1994.

                  At a meeting of the Board of Directors of the Corporation a
resolution was duly adopted, pursuant to Section 242 of the General Corporation
Law of the State of Delaware, setting forth an amended and restated Certificate
of Incorporation of the Corporation and declaring said amendment and
restatement to be advisable. The stockholders of the Corporation duly approved
said proposed amendment and restatement by the affirmative vote of the holders
of at least a majority of the Common Stock at the Annual Meeting of
Stockholders in accordance with Sections 211 and 242 Of the General Corporation
Law of the State of Delaware. The resolutions setting forth the amendment and
restatement is as follows:

                  RESOLVED:  That the Certificate of Incorporation of the
Corporation be and hereby is amended and restated as follows:

       FIRST:     The name of the Corporation is Visual Networks, Inc.  The
date of filing of its original Certificate of Incorporation with the Secretary
of State was December 13, 1994.

       SECOND:    This Amended and Restated Certificate of Incorporation
restates and integrates and further amends the Certificate of Incorporation of
the Corporation and all prior amendments thereto by deleting from the
Certificate of Incorporation, as amended, all provisions thereof and
substituting in lieu thereof the Amended and Restated Certificate of
Incorporation set forth in Paragraph 3 below.

       THIRD:     The text of the Certificate of Incorporation as amended or
supplemented heretofore is further amended and restated hereby to read as
herein set forth in full:

                  1.    Name.  The name of the corporation is Visual Networks,
Inc.

                  2.    Registered Office and Agent.  The address of its
registered office in the State of Delaware is Corporation Trust Center, 1209
Orange Street, in the City of

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Wilmington, County of New Castle. The name of its registered agent at such
address is Corporation Trust Company.

                  3.    Purpose.  The purposes for which the Corporation is
formed are to engage in any lawful act or activity for which corporations may
be organized under the General Corporation Law of Delaware, and to possess and
exercise all of the powers and privileges granted by such law and other laws of
Delaware.

                  4.    Authorized Capital.  The total number of shares of all
classes of stock which the Corporation shall have authority to issue is
55,000,000 shares, of which (i) 50,000,000 shall be shares of common stock, par
value $0.01 per share (the "Common Stock"), and (ii) 5,000,000 shall be shares
of preferred stock, par value $0.01 per share (the "Preferred Stock").

              A.    Common Stock

              (1)  General. The voting, dividend and liquidation rights of the
holders of the Common Stock are subject to and qualified by the rights of the
holders of the Preferred Stock of any series as may be designated by the Board
of Directors upon any issuance of the Preferred Stock of any series.

              (2)  Voting. The holders of the Common Stock are entitled to one
vote for each share held at all meetings of stockholders. There shall be no
cumulative voting.

              (3)  Dividends. Dividends may be declared and paid on the Common
Stock from funds lawfully available therefor as and when determined by the
Board of Directors and subject to any preferential dividend rights of any then
outstanding Preferred Stock.

              (4)  Liquidation. Upon the dissolution or liquidation of the
Corporation, whether voluntary or involuntary, holders of Common Stock will be
entitled to receive all assets of the Corporation available for distribution to
its stockholders, subject to any preferential rights of any then outstanding
Preferred Stock.

              (5)  Redemption. The Common Stock is not redeemable.

              B. Preferred Stock. The Board of Directors expressly is
authorized, subject to limitations prescribed by the Delaware General
Corporation Law and the provisions of this Amended and Restated Certificate of
Incorporation of the Corporation, to provide, by resolution and by filing a
certificate pursuant to the Delaware General Corporation Law, for the issuance
from time to time of the shares of Preferred Stock in one or more series, to
establish from time to time the number of shares to be included in each such
series, and to fix the designation, powers, preferences and other rights of the
shares of each such series and to fix the qualifications, limitations and
restrictions thereon, including, but without limiting the generality of the
foregoing, the following:

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              (1)  the number of shares constituting that series and the
distinctive designation of that series;

              (2)  the dividend rate on the shares of that series, whether
dividends shall be cumulative, and, if so, from which date or dates, and the
relative rights of priority, if any, of payment of dividends on shares of that
series;

              (3)  whether that series shall have voting rights, in addition to
the voting rights provided by law, and, if so, the terms of such voting rights;

              (4)  whether that series shall have conversion privileges, and,
if so, the terms and conditions of such conversion, including provision for
adjustment of the conversion rate in such events as the Board of Directors
shall determine;

              (5)  whether or not the shares of that series shall be
redeemable, and, if so, the terms and conditions of such redemption, including
the dates upon or after which they shall be redeemable, and the amount per
share payable in case of redemption, which amount may vary under different
conditions and at different redemption rates;

              (6)  whether that series shall have a sinking fund for the
redemption or purchase of shares of that series, and, if so, the terms and
amount of such sinking fund;

              (7)  the rights of the shares of that series in the event of
voluntary or involuntary liquidation, dissolution or winding up of the
Corporation, and the relative rights of priority, if any, of payment of shares
of that series; and

              (8)  any other relative powers, preferences, and rights of that
series, and qualifications, limitations or restrictions on that series.

                   5.  Term. The Corporation is to have perpetual existence.

                   6.  Bylaws. The bylaws of the corporation may be altered,
amended or repealed by the vote of a majority of all of the directors or by the
vote of holders of a majority of the stock entitled to vote.

                   7.  Limitation on Liability.  No director of the Corporation
shall be personally liable to the Corporation or to any stockholder of the
Corporation for monetary damages for breach of fiduciary duty as a director,
provided that this provision shall not limit the liability of a director (i)
for any breach of the director's duty of loyalty to the Corporation of its
stockholders, (ii) for acts or omissions not in good faith or which involved
intentional misconduct or a knowing violation of law, (iii) under Section 174
of the General Corporation Law of Delaware, or (iv) for any transaction from
which the director derived an improper personal benefit.

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                  If the General Corporation Law of Delaware or any other
statute of theState of Delaware hereafter is amended to authorize the further
elimination or limitation of the liability of directors of the Corporation,
then the liability of a director of the Corporation shall be limited to the
fullest extent permitted by the statutes of the State of Delaware, as so
amended, and such elimination or limitation of liability shall be in addition
to, and not in lieu of, the limitation on the liability of a director provided
by the foregoing provisions of this Article 7.

                  Any repeal of or amendment to this Article 7 shall be
prospective only and shall not adversely affect any limitation on the liability
of a director of the Corporation existing at the time of such repeal or
amendment.

                  8.       Election of Directors.

                  (A)      General.  Elections of directors need not be by
written ballot unless the By-laws of the Corporation shall so provide. Except
as otherwise provided in this Certificate of Incorporation or a certificate of
designation relating to the rights of the holders of any class or series of
Preferred Stock, voting separately by class or series, to elect additional
directors under specified circumstances, the number of directors of the
Corporation shall be as fixed from time to time by or pursuant to the By-lawsof
the Corporation. No director of the Corporation need be a stockholder of the
Corporation.

                  (B)      Classification. The Board of Directors shall be
classified with respect to the time for which they severally hold office into
three separate classes, Class I, Class II and Class III, which shall be as
nearly equal in number as possible, and shall be adjusted from time to time in
the manner specified in the Bylaws of the Corporation to maintain such
proportionality. Each initial director in Class I shall hold office for a term
expiring at the 2000 annual meeting of stockholders. Each initial director in
Class II shall hold office initially for a term expiring at the 1999 annual
meeting of stockholders. Each initial director in Class III shall hold office
for a term expiring at the 1998 annual meeting of stockholders. Notwithstanding
the foregoing provisions of this Article 8, each director shall serve until
such director's successor is duly elected and qualified or until such
director's earlier death, resignation or removal. At each annual meeting of
stockholders, the successors to the class of directors whose term expires at
that meeting shall be elected to hold office for a term expiring at the annual
meeting of stockholders held in the third year following the year of their
election and until their successors have been duly elected and qualified or
until any such director's earlier death, resignation or removal.

                  9.       Meetings of Stockholders.  Meetings of stockholders
may be held within or without the State of Delaware, as the bylaws of the
Corporation may provide. At such time as the Corporation shall be subject to
the reporting requirements of the Securities Exchange Act of 1934, as amended,
any action required or permitted to be taken by the stockholders of the
Corporation must be effected at a duly called annual or special meeting of
stockholders, and may not be effected by any consent in writing by such
stockholders, unless such consent is unanimous.

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                  10.      Corporate Records.  The books of the Corporation may
be kept (subject to any provision contained in applicable statutes) outside the
State of Delaware at such place or places as may be designated from time to
time by the board of directors or in the bylaws of the Corporation.

                  11.      Right to Amend.  The Corporation reserves the right
to amend, alter, change or repeal any provision contained in this certificate
of incorporation and in any certificate amendatory hereof, in the manner now or
hereafter prescribed by statute, and all rights conferred upon stockholders or
others hereunder or thereunder are granted subject to this reservation.

                  12.      Indemnification.  The Corporation shall, to the
fullest extent permitted by Section 145 of the General Corporation Law of
Delaware, as amended from time to time, indemnify each person who was or is a
party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative
or investigative, by reason of the fact that he is or was, or has agreed to
become, a director or officer of the Corporation, or is or was serving, or has
agreed to serve, at the request of the Corporation, as a director, officer or
trustee of, or in a similar capacity with, another corporation, partnership,
joint venture, trust or other enterprise (including any employee benefit plan),
or by reason of any action alleged to have been taken or omitted in such
capacity, against all expenses (including attorneys' fees), judgments, fines
and amounts paid in settlement actually and reasonably incurred by him or on
his behalf in connection with such action, suit or proceeding and any appeal
therefrom.

                  Indemnification may include payment by the Corporation of
expenses in defending an action or proceeding in advance of the final
disposition of such action or proceeding upon receipt of an undertaking by the
person indemnified to repay such payment if it is ultimately determined that
such person is not entitled to indemnification under this Article 12, which
undertaking may be accepted without reference to the financial ability of such
person to make such repayment.

                  The Corporation shall not indemnify any such person seeking
indemnification in connection with a proceeding (or part thereof) initiated by
such person unless the initiation thereof was approved by the board of
directors of the Corporation.

                  The indemnification rights provided in this Article 12 (i)
shall not be deemed exclusive of any other rights to which those indemnified
may be entitled under any law, agreement or vote of stockholders or
disinterested directors or otherwise and (ii) shall inure to the benefit of the
heirs, executors and administrators of such persons. The Corporation may, to
the extent authorized from time to time by its board of directors, grant
indemnification rights to other employees or agents of the Corporation or other
persons serving the Corporation and such rights may be equivalent to, or
greater or less than, those set forth in this Article 12.

                  FOURTH:  This Amended and Restated Certificate of
Incorporation shall be effective as of the date set forth below.

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                  FIFTH:  This Amended and Restated Certificate of
Incorporation has been advised by the Board and approved by the holders of at
least a majority of the outstanding capital stock of the Corporation.

              IN WITNESS WHEREOF, Visual Networks, Inc. has caused this
Certificate to be signed by Scott Stouffer, its President this 21st day of
July, 1999.

                                           VISUAL NETWORKS, INC.

                                           By:   /s/ Scott Stouffer
                                              ----------------------------------
                                                 Scott Stouffer
                                                 President


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