**EXHIBIT
      3.1**





**FOURTH
      AMENDED AND RESTATED**


**CERTIFICATE
      OF INCORPORATION**


**OF**


**COSINE
      COMMUNICATIONS, INC.**





CoSine
      Communications, Inc., a corporation organized and existing under the laws of
      the
      State of Delaware, hereby certifies as follows:





A.
      The
      name of the corporation is CoSine Communications, Inc. The corporation was
      originally incorporated under the same name and the original Certificate of
      Incorporation of the corporation was filed with the Secretary of State of the
      State of Delaware on May 16, 2000.





B.
      This
      Fourth Amended and Restated Certificate of Incorporation restates and integrates
      and further amends the provisions of the corporation's Certificate of
      Incorporation as heretofore amended. The amendments and restatement herein
      set
      forth have been duly approved by the corporation's Board of Directors and
      stockholders in accordance with Sections 242 and 245 of the General Corporation
      Law of the State of Delaware, with the approval of the corporation's
      stockholders having been duly adopted at a meeting of the stockholders of the
      corporation called for consideration thereof in accordance with Section 242
      of
      the General Corporation Law of the State of Delaware.





C.
      The
      Certificate of Incorporation is hereby restated and further amended to read
      in
      its entirety as follows:





**ARTICLE
      I.**





The
      name
      of the corporation is CoSine Communications, Inc. (the
      "Corporation").





**ARTICLE
      II.**





The
      address of the Corporation's registered office in the State of Delaware is
      2711
      Centerville Road, City of Wilmington, County of New Castle, Delaware 19808.
      The
      name of its registered agent at such address is the Corporation Service
      Company.





**ARTICLE
      III.**





The
      nature of the business or purposes to be conducted or promoted by the
      Corporation is to engage in any lawful act or activity for which corporations
      may be organized under the General Corporation Law of Delaware.





**ARTICLE
      IV.**





1.
      Authorized Shares. The total number of shares of all classes of stock which
      the
      Corporation shall have authority to issue is 25,000,000, of which (i) 22,000,000
      shares, par value $0.0001 per share, are to be of a class designated Common
      Stock ("Common Stock") and (ii) 3,000,000 shares, par value $0.0001 per share,
      are to be of a class designated Preferred Stock ("Preferred Stock"). The
      Preferred Stock may be issued from time to time in one or more series. The
      Board
      of Directors is hereby authorized, subject to any limitations prescribed by
      law,
      to fix by resolution or resolutions the designations, powers, preferences and
      rights, and the qualifications, limitations or restrictions thereof, of each
      such series of Preferred Stock, including without limitation authority to fix
      by
      resolution or resolutions, the dividend rights, dividend rate, conversion
      rights, voting rights, rights and terms of redemption (including sinking fund
      provisions), redemption price or prices, and liquidation preferences of any
      wholly unissued series of Preferred Stock, and the number of shares constituting
      any such series and the designation thereof, or any of the
      foregoing.





2.
      Changes in Number of Designated Shares. The Board of Directors is further
      authorized to increase (but not above the total number of authorized shares
      of
      the class) or decrease (but not below the number of shares of any such series
      then outstanding) the number of shares of any series, the number of which was
      fixed by it, subsequent to the issue of shares of such series then outstanding,
      subject to the powers, preferences and rights, and the qualifications,
      limitations and restrictions thereof stated in the resolution of the Board
      of
      Directors originally fixing the number of shares of such series. If the number
      of shares of any series is so decreased, then the shares constituting such
      decrease shall resume the status which they had prior to the adoption of the
      resolution originally fixing the number of shares of such series.





1


3.
      Limitation on Acquisition of Shares.




(a)
      Certain Acquisitions Prohibited.





(i)
      If an
      individual, partnership, firm, corporation, association, trust, unincorporated
      organization or other entity, as well as any syndicate or group deemed to be
      a
      person under Section 14(d)(2) of the Securities Exchange Act of 1934, as amended
      (each a "Person"), shall attempt to purchase or acquire in any manner
      whatsoever, whether voluntarily or involuntarily, by operation of law or
      otherwise, any shares of capital stock of the Corporation or any option, warrant
      or other right to purchase or acquire capital stock of the Corporation (such
      warrant, option, or security being an "Option") or any securities convertible
      into or exchangeable for capital stock of the Corporation or any interest in
      any
      other entity that directly, indirectly or constructively owns any shares of
      capital stock of the Corporation (any such purchase or acquisition being an
      "Acquisition"), in each case, whether voluntary or involuntary, of record,
      by
      operation of law or otherwise (provided, however, that a transaction that is
      a
      pledge (and not an acquisition of tax ownership for U.S. federal income tax
      purposes) shall not be deemed an Acquisition but a foreclosure pursuant thereto
      shall be deemed to be an Acquisition), and such Acquisition shall affect the
      percentage of capital stock that is treated as owned by a five percent
      stockholder (within the meaning of Section 382 of the Internal Revenue Code
      of
      1986, as amended (the "Code") and the Treasury Regulations promulgated
      thereunder) with respect to the Corporation (a "Five Percent Stockholder"),
      then
      such Person shall be a "Restricted Holder", and such Acquisition shall not
      be
      permitted except as authorized pursuant to this Article IV, Section 3; provided,
      however, that for purposes of determining the existence and identity of, and
      the
      amount of capital stock owned by, any FivePercent Stockholders or Restricted
      Holders, the Corporation is entitled to rely conclusively on (a) the existence
      and absence of filings of Schedules 13D and 13G (or any similar schedules)
      as of
      any date and (b) its actual knowledge of the ownership of its capital stock.
      For
      purposes of this Article IV, Section 3, "capital stock" shall include the Common
      Stock, par value $.0001 of the Corporation.





(ii)
      The
      restrictions contained in this Article IV, Section 3, are for the purpose of
      reducing the risk that any change in stock ownership may jeopardize the
      preservation of the Corporation's U.S. federal, state and local income tax
      attributes under Code Section 382 or equivalent provisions of state or local
      law
      (collectively, the "Tax Benefits"). In connection therewith, and to provide
      for
      the effective policing of these provisions, a Restricted Holder who proposes
      to
      effect an Acquisition, prior to the date of the proposed Acquisition, request
      in
      writing (a "Request") that the Board of Directors of the Corporation review
      the
      proposed Acquisition and authorize or not authorize the proposed Acquisition
      pursuant to subsection (c) hereof. A Request shall be mailed or delivered to
      the
      Secretary of the Corporation at the Corporation's principal place of business
      or
      telecopied to the Corporation's telecopier number at its principal place of
      business. Such Request shall be deemed to have been delivered when actually
      received by the Secretary of the Corporation. A Request shall include (a) the
      name, address and telephone number of the Restricted Holder, (b) a description
      of the interest proposed to be Acquired by the Restricted Holder, (c) the date
      on which the proposed Acquisition is expected to take place, (d) the name of
      the
      intended transferor of the interest to be Acquired by the Restricted Holder,
      and
      (e) a Request that the Board of Directors authorize, if appropriate, the
      Acquisition pursuant to subsection (c) hereof and inform the Restricted Holder
      of its determination regarding the proposed Acquisition. If the Restricted
      Holder seeks to effect an Acquisition, at the next regularly scheduled meeting
      of the Board of Directors following the tenth business day after receipt by
      the
      Secretary of the Corporation of a Request, the Board of Directors will act
      to
      determine whether to authorize the proposed Acquisition described in the Request
      under subsection (c) hereof. The Board of Directors shall conclusively determine
      whether to authorize the proposed Acquisition, in its sole discretion and
      judgment, and shall immediately cause the Restricted Holder making the Request
      to be informed of such determination.





(b)
      Effect of Unauthorized Acquisition. Any Acquisition attempted to be made in
      violation of this Article IV, Section 3, will be null and void. In the event
      of
      an attempted or purported Acquisition by a Restricted Holder in violation of
      this Article IV, Section 3, the Corporation shall be deemed to be the agent
      for
      the transferor of the prohibited shares (the "Prohibited Shares"). The
      Corporation shall be such agent for the limited purpose of consummating a sale
      of the Prohibited Shares to a Person who is not a Restricted Holder (an
      "Eligible Transferee"), which may include, without limitation, the transferor.
      The record ownership of the Prohibited Shares shall remain in the name of the
      transferor until the Prohibited Shares have been sold by the Corporation or
      its
      assignee, as agent, to an Eligible Transferee. Neither the Corporation, as
      agent, nor any assignee of its agency hereunder, shall be deemed to be a
      stockholder of the Corporation nor be entitled to any rights of a stockholder
      of
      the Corporation, including, but not limited to, any right to vote the Prohibited
      Shares or to receive dividends or liquidating distributions in respect thereof,
      if any, but the Corporation or its assignee shall only have the right to sell
      and transfer the Prohibited Shares on behalf of and as agent for the transferor
      to another person or entity; provided, however, that an Acquisition to such
      other person or entity does not violate the provisions of this Article IV,
      Section 3. The rights to vote and to receive dividends and liquidating
      distributions with respect to the Prohibited Shares shall remain with the
      transferor. The intended transferee shall not be entitled to any rights of
      stockholders of the Corporation, including, but not limited to, the rights
      to
      vote or to receive dividends and liquidating distributions with respect to
      the
      Prohibited Shares. In the event of a permitted sale and transfer, whether by
      the
      Corporation or its assignee, as agent, the proceeds of such sale shall be
      applied first, to reimburse the Corporation or its assignee for any expenses
      incurred by the Corporation acting in its role as the agent for the sale of
      the
      Prohibited Shares, second, to the extent of any remaining proceeds, to reimburse
      the intended transferee for any payments made to the transferor by such intended
      transferee for such shares, and the remainder, if any, to the original
      transferor.





2


(c)
      Authorization of Acquisition of Capital Stock by a Restricted Holder. The Board
      of Directors may authorize an Acquisition by a Restricted Holder, if, in its
      sole discretion and judgment it determines that the Acquisition is in the best
      interests of the Corporation and its stockholders. In deciding whether to
      approve any proposed Acquisition by a Restricted Holder, the Board of Directors
      may seek the advice of counsel with respect to the Corporation's preservation
      of
      the Tax Benefits and may request all relevant information from the Restricted
      Holder with respect to all capital stock directly or indirectly owned by such
      Restricted Holder. Any Person who makes a Request of the Board of Directors
      pursuant to this subsection (c) to effect an Acquisition shall reimburse the
      Corporation, on demand, for all reasonable costs and expenses incurred by the
      Corporation with respect to any proposed Acquisition, including, without
      limitation, the Corporation's reasonable costs and expenses incurred in
      determining whether to authorize that proposed Acquisition.





(d)
      Certain Indirect Prohibited Acquisitions. In the event an Acquisition would
      be
      in violation of this Article IV, Section 3, as a result of attribution to the
      intended transferee of the ownership of capital stock by a Person (an "Other
      Person") who is not controlling, controlled by or under common control with
      the
      intended transferee, which ownership is nevertheless attributed to the intended
      transferee, the restrictions contained in this Article IV, Section 3, shall
      not
      apply in a manner that would invalidate any Acquisition to such Other Person,
      and the intended transferee and any Persons controlling, controlled by or under
      common control with the intended transferee (collectively, the "Intended
      Transferee Group") shall automatically be deemed to have transferred to the
      Corporation, sufficient capital stock (which capital stock shall (i) consist
      only of capital stock held legally or beneficially, whether directly or
      indirectly, by any member of the Intended Transferee Group, but not capital
      stock held through any Other Person, other than shares held through a Person
      acting as agent or fiduciary for any member of the Intended Transferee Group,
      (ii) be deemed transferred to the Corporation, in the inverse order in which
      it
      was acquired by members of the Intended Transferee Group, and (iii) be treated
      as Prohibited Shares) to cause the intended transferee, following such transfer
      to the Corporation, not to be in violation of the restrictions contained in
      this
      Article IV, Section 3; provided, however, that to the extent the foregoing
      provisions of this subsection (d) would not be effective to prevent an
      Acquisition in violation of this Article IV, Section 3, the restrictions
      contained in this Article IV, Section 3, shall apply to such other capital
      stock
      owned by the intended transferee (including capital stock actually owned by
      Other Persons), in a manner designed to minimize the amount of capital stock
      subject to the restrictions contained in this Article IV, Section 3, or as
      otherwise determined by the Board of Directors to be necessary to prevent an
      Acquisition in violation of the restrictions contained in this Article IV,
      Section 3 (which capital stock shall be treated as Prohibited
      Shares).





(e)
      Prompt Enforcement; Further Actions. After learning of an Acquisition by a
      Restricted Holder, the Corporation shall demand the surrender, or cause to
      be
      surrendered, to it, the certificates representing the Prohibited Shares, or
      any
      proceeds received upon a sale of the Prohibited Shares, and any dividends or
      other distributions made with respect to the Prohibited Shares. If such
      surrender is not made within 30 business days from the date of such demand,
      the
      Corporation may institute legal proceedings to compel such transfer; provided,
      however, that nothing in this subsection (e) shall (i) be deemed inconsistent
      with the Acquisition of the Prohibited Shares being deemed null and void
      pursuant to subsection (b) hereof, (ii) preclude the Corporation in its
      discretion from immediately bringing legal proceedings without a prior demand,
      or (iii) cause any failure of the Corporation to act within the time periods
      set
      forth in this subsection (c) to constitute a waiver or loss of any right of
      the
      Corporation under this Article IV, Section 3.





(f)
      Damages. Any Restricted Holder who knowingly violates the provisions of this
      Article IV, Section 3, and any persons controlling, controlled by or under
      common control with such a Restricted Holder, shall be jointly and severally
      liable to the Corporation for, and shall indemnify and hold the Corporation
      harmless against, any and all damages suffered as a result of such violation,
      including but not limited to damages resulting from a reduction in or
      elimination of the Corporation's ability to utilize its Tax Benefits, and
      attorneys' and auditors' fees incurred in connection with such
      violation.





3


(g)
      Legend on Certificates. All certificates for shares of Common Stock issued
      by
      the Corporation shall conspicuously bear the following legend: "The Second
      Amended and Restated Certificate of Incorporation, as amended (the "Certificate
      of Incorporation") of the Corporation contains restrictions prohibiting the
      purchase or acquisition (collectively, the "Acquisition") of any capital stock
      without the authorization of the Board of Directors of the Corporation (the
      "Board of Directors"), if such Acquisition affects the percentage of capital
      stock that is treated as owned by a five percent stockholder (within the meaning
      of Section 382 of the Internal Revenue Code of 1986, as amended (the "Code")
      and
      the Treasury Regulations promulgated thereunder), and such Acquisition would,
      in
      the sole discretion and judgment of the Board of Directors, jeopardize the
      Corporation's preservation of its U.S. federal income tax attributes pursuant
      to
      Section 382 of the Code and is not otherwise in the best interests of the
      Corporation and its stockholders. The Corporation will furnish without charge
      to
      the holder of record of this certificate a copy of the Certificate of
      Incorporation, containing the above-referenced restrictions on acquisitions
      of
      stock, upon written request to the Corporation at its principal place of
      business."





(h)
      Conditions to Acquisition; Responsibilities of Transfer Agent. The Corporation
      may require, as a condition to the registration of the Acquisition of any of
      its
      capital stock or the payment of any distribution on any of its capital stock,
      that the intended transferee or payee furnish to the Corporation all information
      reasonably requested by the Corporation with respect to all the direct or
      indirect ownership interests in such capital stock. The Corporation may make
      such arrangements or issue such instructions to its stock transfer agent as
      may
      be determined by the Board of Directors to be necessary or advisable to
      implement this Article IV, Section 3, including, without limitation, instructing
      the transfer agent not to register any Acquisition of capital stock on the
      Corporations stock transfer records if it has knowledge that such Acquisition
      is
      prohibited by this Article IV, Section 3, and/or authorizing such transfer
      agent
      to require an affidavit from a intended transferee regarding such Person's
      actual and constructive ownership of capital stock and other evidence that
      an
      Acquisition will not be prohibited by this Article IV, Section 3, as a condition
      to registering any Acquisition.





(i)
      Authority of Board of Directors to Interpret. Nothing contained in this Article
      IV, Section 3, shall limit the authority of the Board of Directors to take
      such
      other action to the extent permitted by law as it deems necessary or advisable
      to protect the Corporation and preserve the Tax Benefits. Without limiting
      the
      generality of the foregoing, in the event of a change in law making one or
      more
      of the following actions necessary or desirable, the Board of Directors may,
      by
      adopting a written resolution of the Board of Directors, modify the definitions
      of any terms or conditions set forth in this Article IV, Section 3, or modify
      the definitions of any terms or conditions of this Article IV, Section 3, as
      appropriate to prevent an ownership change for purposes of Section 382 of the
      Code as a result of any changes in applicable Treasury Regulations or otherwise;
      provided, however, that the Board of Directors shall not cause there to be
      such
      acceleration, extension, change or modification unless it concludes in writing
      that such action is reasonably necessary or advisable to preserve the Tax
      Benefits or that the continuation of these restrictions is no longer reasonably
      necessary for the preservation of the Tax Benefits, and its conclusion is based
      upon a written opinion of tax counsel to the Corporation. The Corporation and
      the members of the Board of Directors shall be fully protected in relying in
      good faith upon the information, opinions, reports or statements of the chief
      executive officer, the chief financial officer or the chief accounting officer
      of the Corporation (or the person or persons performing the functions of such
      officers) or of the Corporation's legal counsel, independent auditors, transfer
      agent, investment bankers or other employees and agents in making the
      determinations and findings contemplated by this Article IV, Section 3, and
      the
      members of the Board of Directors shall not be responsible for any good faith
      errors made in connection therewith.





(j)
      Severability. If any part of the provisions of this Article IV, Section 3,
      are
      judicially determined to be invalid or otherwise unenforceable, such invalidity
      or unenforceability shall not affect the remainder of the provisions of this
      Article IV, Section 3, which shall be thereafter interpreted as if the invalid
      or unenforeceable part were not contained herein, and, to the maximum extent
      possible, in a manner consistent with preserving the ability of the Corporation
      to utilize to the greatest extent possible the Corporation's Tax
      Benefit.





(k)
      Expiration. The provisions of this Article IV, Section 3, shall apply until
      such
      time as the Board of Directors determines in its sole discretion that the
      provisions of this Article IV, Section 3, are no longer necessary for the
      preservation of the Corporation's Tax Benefits.





4


4.
      Rights
      and Preferences of Preferred Stock.  The
      designation and amount of the initial series of Preferred Stock and the powers,
      preferences and relative, participating, optional and other special rights
      of
      the shares of such series, and the qualifications, limitations or restrictions
      thereof are as follows:





(a)  Designation
      and Amount. The shares of such series will be designated as Series A Junior
      Participating Preferred Stock (the “Series A Preferred”) and the number of
      shares constituting the Series A Preferred is 220,000. Such number of shares
      may
      be increased or decreased by resolution of the Board; provided, however, that
      no
      decrease will reduce the number of shares of Series A Preferred to a number
      less
      than the number of shares then outstanding plus the number of shares reserved
      for issuance upon the exercise of outstanding options, rights or warrants or
      upon the conversion of any outstanding securities issued by the Corporation
      any
      convertible into Series A Preferred.





(b)  Dividends
      and Distributions.





(i)
      Subject to the rights of the holders of any shares of any series of Preferred
      Stock ranking prior to the Series A Preferred with respect to dividends, the
      holders of shares of Series A Preferred, in preference to the holders of Common
      Stock of the Corporation, and of any other junior stock, will be entitled to
      receive, when, as and if declared by the Board out of funds legally available
      for the purpose, dividends payable in cash (except as otherwise provided below)
      on such dates as are from time to time established for the payment of dividends
      on the Common Stock (each such date being referred to herein as a “ Dividend
      Payment Date”), commencing on the first Dividend Payment Date after the first
      issuance of a share or fraction of a share of Series A Preferred (the “First
      Dividend Payment Date”), in an amount per share (rounded to the nearest cent)
      equal to, subject to the provision for adjustment hereinafter set forth, one
      hundred times the aggregate per share amount of all cash dividends, and one
      hundred times the aggregate per share amount (payable in kind) of all non-cash
      dividends, other than a dividend payable in shares of Common Stock or a
      subdivision of the outstanding shares of Common Stock (by reclassification
      or
      otherwise), declared on the Common Stock since the immediately preceding
      Dividend Payment Date or, with respect to the First Dividend Payment Date,
      since
      the first issuance of any share or fraction of a share of Series A Preferred.
      In
      the event that the Corporation at any time (i) declares a dividend on the
      outstanding shares of Common Stock payable in shares of Common Stock, (ii)
      subdivides the outstanding shares of Common Stock, (iii) combines the
      outstanding shares of Common Stock into a smaller number of shares, or (iv)
      issues any shares of its capital stock in a reclassification of the outstanding
      shares of Common Stock (including any such reclassification in connection with
      a
      consolidation or merger in which the Corporation is the continuing or surviving
      corporation), then, in each such case and regardless of whether any shares
      of
      Series A Preferred are then issued or outstanding, the amount to which holders
      of shares of Series A Preferred would otherwise be entitled immediately prior
      to
      such event under clause (ii) of the preceding sentence will be adjusted by
      multiplying such amount by a fraction, the numerator of which is the number
      of
      shares of Common Stock outstanding immediately after such event and the
      denominator of which is the number of shares of Common Stock that were
      outstanding immediately prior to such event.





(ii)
      The
      Corporation will declare a dividend on the Series A Preferred as provided in
      the
      immediately preceding paragraph immediately after it declares a dividend on
      the
      Common Stock (other than a dividend payable in shares of Common Stock). Each
      such dividend on the Series A Preferred will be payable immediately prior to
      the
      time at which the related dividend on the Common Stock is payable.





(iii)
      Dividends will accrue on outstanding shares of Series A Preferred from the
      Dividend Payment Date next preceding the date of issue of such shares, unless
      (i) the date of issue of such shares is prior to the record date for the First
      Dividend Payment Date, in which case dividends on such shares will accrue from
      the date of the first issuance of a share of Series A Preferred or (ii) the
      date
      of issue is a Dividend Payment Date or is a date after the record date for
      the
      determination of holders of shares of Series A Preferred entitled to receive
      a
      dividend and before such Dividend Payment Date, in either of which events such
      dividends will accrue from such Dividend Payment Date. Accrued but unpaid
      dividends will cumulate from the applicable Dividend Payment Date but will
      not
      bear interest. Dividends paid on the shares of Series A Preferred in an amount
      less than the total amount of such dividends at the time accrued and payable
      on
      such shares will be allocated pro rata on a share-by-share basis among all
      such
      shares at the time outstanding. The Board may fix a record date for the
      determination of holders of shares of Series A Preferred entitled to receive
      payment of a dividend or distribution declared thereon, which record date will
      be not more than 60 calendar days prior to the date fixed for the payment
      thereof.





5


(c)  Voting
      Rights. The holders of shares of Series A Preferred will have the following
      voting rights:





(i)
      Subject to the provision for adjustment hereinafter set forth, each share of
      Series A Preferred will entitle the holder thereof to one hundred votes on
      all
      matters submitted to a vote of the stockholders of the Corporation. In the
      event
      the Corporation at any time (i) declares a dividend on the outstanding shares
      of
      Common Stock payable in shares of Common Stock, (ii) subdivides the outstanding
      shares of Common Stock, (iii) combines the outstanding shares of Common Stock
      into a smaller number of shares, or (iv) issues any shares of its capital stock
      in a reclassification of the outstanding shares of Common Stock (including
      any
      such reclassification in connection with a consolidation or merger in which
      the
      Corporation is the continuing or surviving corporation), then, in each such
      case
      and regardless of whether any shares of Series A Preferred are then issued
      or
      outstanding, the number of votes per share to which holders of shares of Series
      A Preferred would otherwise be entitled immediately prior to such event will
      be
      adjusted by multiplying such number by a fraction, the numerator of which is
      the
      number of shares of Common Stock outstanding immediately after such event and
      the denominator of which is the number of shares of Common Stock that were
      outstanding immediately prior to such event.





(ii)
      Except as otherwise provided herein, in any other Preferred Stock Designation
      creating a series of Preferred Stock or any similar stock, or by law, the
      holders of shares of Series A Preferred and the holders of shares of Common
      Stock and any other capital stock of the Corporation having general voting
      rights will vote together as one class on all matters submitted to a vote of
      stockholders of the Corporation.





(iii)
      Except as set forth in the Amended and Restated Certificate of Incorporation
      or
      herein, or as otherwise provided by law, holders of shares of Series A Preferred
      will have no voting rights.





(d)  Certain
      Restrictions.





(i)
      Whenever dividends or other dividends or distributions payable on the Series
      A
      Preferred are in arrears, thereafter and until all accrued and unpaid dividends
      and distributions, whether or not declared, on shares of Series A Preferred
      outstanding have been paid in full, the Corporation will not:





(a)
      Declare or pay dividends, or make any other distributions, on any shares of
      stock ranking junior (either as to dividends or upon liquidation, dissolution
      or
      winding up) to the shares of Series A Preferred;





(b)
      Declare or pay dividends, or make any other distributions, on any shares of
      stock ranking on a parity (either as to dividends or upon liquidation,
      dissolution or winding up) with the shares of Series A Preferred, except
      dividends paid ratably on the shares of Series A Preferred and all such parity
      stock on which dividends are payable or in arrears in proportion to the total
      amounts to which the holders of all such shares are then entitled;





(c)
      Redeem, purchase or otherwise acquire for consideration shares of any stock
      ranking junior (either as to dividends or upon liquidation, dissolution or
      winding up) to the shares of Series A Preferred; provided , however ,
      that
      the Corporation may at any time redeem, purchase or otherwise acquire shares
      of
      any such junior stock in exchange for shares of any stock of the Corporation
      ranking junior (either as to dividends or upon dissolution, liquidation or
      winding up) to the shares of Series A Preferred; or





(d)
      Redeem, purchase or otherwise acquire for consideration any shares of Series
      A
      Preferred, or any shares of stock ranking on a parity with the shares of Series
      A Preferred, except in accordance with a purchase offer made in writing or
      by
      publication (as determined by the Board) to all holders of such shares upon
      such
      terns as the Board, after consideration of the respective annual dividend rates
      and other relative rights and preferences of the respective series and classes,
      may determine in good faith will result in fair and equitable treatment among
      the respective series or classes.





(ii)
      The
      Corporation will not permit any majority-owned subsidiary of the Corporation
      to
      purchase or otherwise acquire for consideration any shares of stock of the
      Corporation unless the Corporation could, under paragraph (a) of this Article
      IV, Section 4, purchase or otherwise acquire such shares at such time and in
      such manner.





6


(e)  Reacquired
      Shares. Any shares of Series A Preferred purchased or otherwise acquired by
      the
      Corporation in any manner whatsoever will be retired and canceled promptly
      after
      the acquisition thereof. All such shares will upon their cancellation become
      authorized but unissued shares of Preferred Stock and may be reissued as part
      of
      a new series of Preferred Stock subject to the conditions and restrictions
      on
      issuance set forth herein, in the Amended and Restated Certificate of
      Incorporation of the Corporation, or in any other Preferred Stock Designation
      creating a series of Preferred Stock or any similar stock or as otherwise
      required bylaw.





(f)  Liquidation,
      Dissolution or Winding Up. Upon any liquidation, dissolution or winding up
      of
      the Corporation, no distribution will be made (a) to the holders of shares
      of
      stock ranking junior (either as to dividends or upon liquidation, dissolution
      or
      winding up) to the shares of Series A Preferred unless, prior thereto, the
      holders of shares of Series A Preferred have received $100 per share, plus
      an
      amount equal to accrued and unpaid dividends and distributions thereon, whether
      or not declared, to the date of such payment; provided , however ,
      that
      the holders of shares of Series A Preferred will be entitled to receive an
      aggregate amount per share, subject to the provision for adjustment hereinafter
      set forth, equal to one hundred times the aggregate amount to be distributed
      per
      share to holders of shares of Common Stock or (b) to the holders of shares
      of
      stock ranking on a parity (either as to dividends or upon liquidation,
      dissolution or winding up) with the shares of Series A Preferred, except
      distributions made ratably on the shares of Series A Preferred and all such
      parity stock in proportion to the total amounts to which the holders of all
      such
      shares are entitled upon such liquidation, dissolution or winding up. In the
      event the Corporation at any time (i) declares a dividend on the outstanding
      shares of Common Stock payable in shares of Common Stock, (ii) subdivides the
      outstanding shares of Common Stock, (iii) combines the outstanding shares of
      Common Stock into a smaller number of shares, or (iv) issues any shares of
      its
      capital stock in a reclassification of the outstanding shares of Common Stock
      (including any such reclassification in connection with a consolidation or
      merger in which the Corporation is the continuing or surviving corporation),
      then, in each such case and regardless of whether any shares of Series A
      Preferred are then issued or outstanding, the aggregate amount to which each
      holder of shares of Series A Preferred would otherwise be entitled immediately
      prior to such event under the proviso in clause (a) of the preceding sentence
      will be adjusted by multiplying such amount by a fraction, the numerator of
      which is the number of shares of Common Stock outstanding immediately after
      such
      event and the denominator of which is the number of shares of Common Stock
      that
      were outstanding immediately prior to such event.





(g)  Consolidation,
      Merger, Etc. In the event that the Corporation enters into any consolidation,
      merger, combination or other transaction in which the shares of Common Stock
      are
      exchanged for or changed into other stock or securities, cash and/or any other
      property, then, in each such case, each share of Series A Preferred will at
      the
      same time be similarly exchanged for or changed into an amount per share,
      subject to the provision for adjustment hereinafter set forth, equal to one
      hundred times the aggregate amount of stock, securities, cash and/or any other
      property (payable in kind), as the case may be, into which or for which each
      share of Common Stock is changed or exchanged. In the event the Corporation
      at
      any time (a) declares a dividend on the outstanding shares of Common Stock
      payable in shares of Common Stock, (b) subdivides the outstanding shares of
      Common Stock, (c) combines the outstanding shares of Common Stock in a smaller
      number of shares, or (d) issues any shares of its capital stock in a
      reclassification of the outstanding shares of Common Stock (including any such
      reclassification in connection with a consolidation or merger in which the
      Corporation is the continuing or surviving corporation), then, in each such
      case
      and regardless of whether any shares of Series A Preferred are then issued
      or
      outstanding, the amount set forth in the preceding sentence with respect to
      the
      exchange or change of shares of Series A Preferred will be adjusted by
      multiplying such amount by a fraction, the numerator of which is the number
      of
      shares of Common Stock outstanding immediately after such event and the
      denominator of which is the number of shares of Common Stock that were
      outstanding immediately prior to such event.





(h)  Redemption.
      The shares of Series A Preferred are not redeemable.





(i)  Rank.
      The
      Series A Preferred rank, with respect to the payment of dividends and the
      distribution of assets, junior to all other series of the Corporation’s
      Preferred Stock.





(j)  Amendment.
      Notwithstanding anything contained in the Certificate of Incorporation of the
      Corporation to the contrary and in addition to any other vote required by
      applicable law, the Certificate of Incorporation of the Corporation may not
      be
      amended in any manner that would materially alter or change the powers,
      preferences or special rights of the Series A Preferred so as to affect them
      adversely without the affirmative vote of the holders of at least 80% of the
      outstanding shares of Series A Preferred, voting together as a single
      series.





7


**ARTICLE
      V.**





The
      Corporation is to have perpetual existence.





**ARTICLE
      VI.**





Elections
      of directors need not be by written ballot unless the Bylaws of the Corporation
      shall so provide.





**ARTICLE
      VII.**





1.
      The
      management of the business and the conduct of the affairs of the Corporation
      shall be vested in its Board of Directors. The number of directors which
      constitute the whole Board of Directors of the Corporation shall be fixed by,
      or
      determined in the manner provided in, the Bylaws of the
      Corporation.





2.
      Each
      director who is serving as a director on the date of the Third Amended and
      Restated Certificate of Incorporation shall hold office until the next annual
      meeting of stockholders after such date and until such director's successor
      is
      duly elected and qualified or until such director's earlier death, resignation
      or removal, notwithstanding that such director may have been elected for a
      term
      that extended beyond the date of such next annual meeting of stockholders.
      At
      each annual meeting of stockholders after the date of the Third Amended and
      Restated Certificate of Incorporation, directors elected at such annual meeting
      shall hold office until the next annual meeting of stockholders and until such
      director's successor is duly elected and qualified or until such director's
      earlier death, resignation or removal.





3.
      Subject to the rights of the holders of any series of Preferred Stock, any
      vacancies on the Board of Directors resulting from death, resignation,
      disqualification, removal, or other causes shall be filled by either (i) the
      affirmative vote of the holders of a majority of the voting power of the
      then-outstanding shares of voting stock of the corporation entitled to vote
      generally in the election of directors ("Voting Stock") voting together as
      a
      single class; or (ii) by the affirmative vote of a majority of the remaining
      directors then in office, even though less than a quorum of the Board of
      Directors. Newly created directorships resulting from any increase in the number
      of directors shall, unless the Board of Directors determines by resolution
      that
      any such newly created directorship shall be filled by the stockholders, be
      filled only by the affirmative vote of the directors then in office, even though
      less than a quorum of the Board of Directors. Any director elected in accordance
      with the preceding two sentences shall hold office until the next annual meeting
      of stockholders and until such director's successor is duly elected and
      qualified or until such director's earlier death, resignation or
      removal.




4.
      The
      affirmative vote of sixty-six and two-thirds percent (66-2/3%) of the voting
      power of the then outstanding shares of Voting Stock, voting together as a
      single class, shall be required for the adoption, amendment or repeal of the
      following sections or Articles of the corporation's Bylaws by the stockholders
      of this corporation: 2.2 (Annual Meeting), 2.3 (Special Meeting),


2.5
      (Advance Notice of Stockholder Nominees and Stockholder Business), 3.2 (Number
      of Directors) and Article VI (Indemnification).





5.
      No
      action shall be taken by the stockholders of the corporation except at an annual
      or special meeting of the stockholders called in accordance with the Bylaws,
      and
      no action shall be taken by the stockholders by written consent.





6.
      Subject to the rights of any series of Preferred Stock, any director, or the
      entire Board of Directors, may be removed from office at any time (i) with
      cause
      by the affirmative vote of the holders of at least a majority of the voting
      power of all of the then-outstanding shares of the Voting Stock, voting together
      as a single class; or (ii) without cause by the affirmative vote of the holders
      of at least sixty-six and two-thirds percent (66-2/3%) of the voting power
      of
      all of the then-outstanding shares of the Voting Stock.





**ARTICLE
      VIII.**





In
      furtherance and not in limitation of the powers conferred by statute, the Board
      of Directors is expressly authorized to adopt, alter, amend or repeal the Bylaws
      of the Corporation.





8


**ARTICLE
      IX.**





1.
      To the
      fullest extent permitted by the Delaware General Corporation Law as the same
      exists or as may hereafter be amended, no director of the Corporation shall
      be
      personally liable to the Corporation or its stockholders for monetary damages
      for breach of fiduciary duty as a director.




2.
      The
      Corporation may indemnify to the fullest extent permitted by law any person
      made
      or threatened to be made a party to any threatened, pending or completed action,
      suit or proceeding, whether criminal, civil, administrative or investigative,
      by
      reason of the fact that he, his testator or intestate is or was a director,
      officer, employee or agent of the Corporation or any predecessor of the
      Corporation or serves or served at any other enterprise as a director, officer,
      employee or agent at the request of the Corporation or any predecessor to the
      Corporation.





3.
      Neither any amendment nor repeal of this Article XI, nor the adoption of any
      provision of this Certificate of Incorporation inconsistent with this Article
      XI, shall eliminate or reduce the effect of this Article XI, in respect of
      any
      matter occurring, or any action or proceeding accruing or arising or that,
      but
      for this Article XI, would accrue or arise, prior to such amendment, repeal
      or
      adoption of an inconsistent provision.





**ARTICLE
      X.**





Advance
      notice of stockholder nominations for the election of directors of the
      Corporation and of business to be brought by stockholders before any meeting
      of
      stockholders of the Corporation shall be given in the manner and to the extent
      provided in the Bylaws of the Corporation. Business transacted at special
      meetings of stockholders shall be confined to the purpose or purposes stated
      in
      the notice of meeting.





**ARTICLE
      XI.**





**** Notwithstanding
      any other provisions of this Certificate of Incorporation or any provision
      of
      law that might otherwise permit a lesser vote or no vote, but in addition to
      any
      affirmative vote of the holders of any particular class or series of Voting
      Stock required by law, this Certificate of Incorporation or any Preferred Stock
      Designation, the affirmative vote of the holders of at least sixty-six and
      two-thirds percent (66-2/3%) of the voting power of all of the then-outstanding
      shares of Voting Stock, voting together as a single class, shall be required
      to
      alter, amend or repeal Article VI, Article VII, Article VIII, Article IX,
      Article X or this Article XI.





**ARTICLE
      XII.**





The
      Corporation reserves the right to amend, alter, change or repeal any provision
      contained in this Certificate of Incorporation, in the manner now or hereafter
      prescribed by statute (subject to compliance with the requirements of Article
      X), and all rights conferred herein are granted subject to this
      reservation.





**ARTICLE
      XIII.**





Meetings
      of stockholders may be held within or without the State of Delaware, as the
      Bylaws may provide. The books of the Corporation may be kept (subject to any
      provision contained in the laws of the State of Delaware) outside of 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.





The
      foregoing Fourth Amended and Restated Certificate of Incorporation of CoSine
      Communications, Inc. is the act and deed of this corporation, and the statements
      therein are true.





IN
      WITNESS WHEREOF, the Board of Directors of the Company has caused this Fourth
      Amended and Restated Certificate of Incorporation to be signed by Terry Gibson,
      its President and Chief Executive Officer.




Dated:
              May 24, 2006.
            COSINE
              COMMUNICATIONS, INC.By:
            /s/ Terry
              GibsonTerry
                Gibson
              President
                and Chief Executive Officer


9