<PAGE>

   As filed with the Securities and Exchange Commission on January 19, 2001.
                                                    Registration No. 333-_______
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                             ----------------------

                                    FORM S-8
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933
                             ----------------------

                              SONUS NETWORKS, INC.
             (Exact Name of Registrant as Specified in Its Charter)

                                    DELAWARE
         (State or Other Jurisdiction of Incorporation or Organization)

                                   04-3387074
                      (I.R.S. Employer Identification No.)

      5 CARLISLE ROAD, WESTFORD, MASSACHUSETTS                    01886
      (Address of Principal Executive Offices)                  (Zip Code)

                             ----------------------

   TELECOM TECHNOLOGIES, INC. AMENDED AND RESTATED 1998 EQUITY INCENTIVE PLAN

                    SONUS NETWORKS, INC. 2000 RETENTION PLAN
                            (Full Title of the Plans)

                             ----------------------

                                 HASSAN M. AHMED
                                    President
                           and Chief Executive Officer
                              Sonus Networks, Inc.
                                 5 Carlisle Road
                               Westford, MA 01886
                     (Name and Address of Agent for Service)

                                 (978) 692-8999
           Telephone Number, Including Area Code, of Agent For Service

                             ----------------------

                                    Copy to:
                              DAVID L. ENGEL, ESQ.
                             JOHAN V. BRIGHAM, ESQ.
                                BINGHAM DANA LLP
                               150 Federal Street
                           Boston, Massachusetts 02110
                                 (617) 951-8000

<TABLE>
<CAPTION>
                         CALCULATION OF REGISTRATION FEE
================================================================================================================================
                                                                   Proposed          Proposed
                 Title Of                                           Maximum          Maximum
                Securities                        Amount          Offering          Aggregate                     Amount Of
                  To Be                           To Be           Price Per          Offering                   Registration
                Registered                      Registered          Share             Price                          Fee
--------------------------------------------------------------------------------------------------------------------------------
<S>                                             <C>               <C>             <C>                       <C>
Common Stock, $0.001 par value per share
to be issued under the Equity Incentive
Plan                                            1,067,156         $0.80 (1)         $853,724.80 (1)                     $213.43
--------------------------------------------------------------------------------------------------------------------------------
                                                1,182,517         $1.00 (1)       $1,182,517.00 (1)                     $295.63
--------------------------------------------------------------------------------------------------------------------------------
                                                  37,500          $1.50 (1)          $56,250.00 (1)                      $14.06
--------------------------------------------------------------------------------------------------------------------------------
                                                 132,033          $2.00 (1)         $264,066.00 (1)                      $66.02
--------------------------------------------------------------------------------------------------------------------------------
Common Stock, $0.001 par value per share
to be issued under the 2000 Retention Plan      3,000,000       $26.938 (2)      $80,814,000.00 (2)                  $20,203.50
--------------------------------------------------------------------------------------------------------------------------------
TOTAL FEE TO BE PAID BY REGISTRANT                                                                                   $20,793.00
================================================================================================================================
</TABLE>

<PAGE>

(1)  Based on the maximum exercise price of the shares subject to outstanding
     options issued under the Registrant's Equity Incentive Plan. Such shares
     are issuable upon exercise of outstanding options with fixed exercise
     prices. Pursuant to Rule 457(h)(1), the aggregate offering price and the
     fee have been computed upon the basis of the price at which the options may
     be exercised. The offering price per share set forth for such shares is the
     exercise price per share at which such options are exercisable.

(2)  Pursuant to Rule 457(h)(1), the aggregate offering price and amount of the
     registration fee has been computed with respect to those shares of the
     common stock issuable under the 2000 Retention Plan that are being
     registered hereunder. For the purpose of calculating the filing fee only,
     the average high and low sale price of the Registrant's common stock as
     quoted on Nasdaq on January 16, 2001 has been used.



<PAGE>

                                     PART II

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents filed by Sonus Networks, Inc., file no.
000-30229, with the Securities and Exchange Commission (the "SEC") are hereby
incorporated by reference into this Registration Statement:

<TABLE>
<CAPTION>
                                                                                                    PERIOD
                                                                                                    ------
           <S>                                                                       <C>
           The description of the common stock of Sonus Networks, Inc.
           (the "Registrant"), $0.001 par value per share, contained in the
           Registrant's Registration Statement on Form 8-A pursuant to Section
           12(g) of the Securities Exchange Act....................................  Filed April 5, 2000


           Quarterly Reports on Form 10-Q..........................................  Quarters ended, June 30, 2000 and
                                                                                     September 30, 2000


           Current Reports on Form 8-K.............................................  Filed on October 13, 2000 and
                                                                                     November 17, 2000

           Prospectus filed pursuant to Rule 424(b)(1) (file no. 333-52682)......... Filed January 12, 2001
</TABLE>

         In addition, all documents filed pursuant to Sections 13(a), 13(c), 14
and 15(d) of the Exchange Act subsequent to the date of this Registration
Statement and prior to the filing of a post-effective amendment which indicates
that all securities registered hereby have been sold or which deregisters all of
such securities then remaining unsold shall be incorporated by reference into
this Registration Statement as of the filing date of each.

ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         As of January 15, 2001, 6 attorneys at Bingham Dana LLP, outside
corporate counsel for the Registrant, owned, in the aggregate, 161,781 shares of
Sonus Common Stock.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the Delaware General Corporation law empowers a Delaware
corporation to indemnify its officers and directors and certain other persons to
the extent and under the circumstances set forth therein.

         The Fourth Amended and Restated Certificate of Incorporation of the
Registrant and the Amended and Restated By-Laws of the Registrant, as amended to
date, provide for indemnification of officers and directors of the Registrant
and certain other persons against liabilities and expenses incurred by any of
them in certain stated proceedings and under certain stated conditions.

         The Registrant may maintain insurance for the benefit of its directors,
officers, employees, agents and certain other persons, insuring such persons
against any expense, liability, or loss, including liability under the
securities laws.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

<PAGE>

         Not applicable.

ITEM 8.  EXHIBITS.

         The following exhibits are filed as part of this Registration
Statement:

<TABLE>
<CAPTION>
EXHIBIT NO.                                 DESCRIPTION OF DOCUMENTS
-----------                                 ------------------------
<S>               <C>
         4.1      Fourth Amended and Restated Certificate of Incorporation of the Registrant,
                  incorporated by reference to Exhibit No. 3.1 to the Registrant's Registration
                  Statement on Form S-1 (file No. 333-32206).

         4.2.     Amended and Restated By-Laws of the Registrant, incorporated by reference to
                  Exhibit No. 3.2 to the Registrant's Registration Statement on Form S-1 (file No. 333-32206).

         4.3      telecom technologies, inc. Amended and Restated 1998 Equity Incentive Plan, as
                  amended, incorporated by reference to Exhibit No. 10.3 to the Registrant's
                  Registration Statement on Form S-4 (file No. 333-52682).

         4.4      Sonus Networks, Inc. 2000 Retention Plan incorporated by reference to Exhibit
                  No. 10.2 to the Registrant's Registration Statement on Form S-4 (file No. 333-52682).

         5        Opinion of Bingham Dana LLP as to the legality of the securities being registered.

         23.1     Consent of Arthur Andersen LLP, independent accountants, dated January 18, 2001.

         23.2     Consent of Arthur Andersen LLP, independent accountants, dated January 18, 2001.

         23.3     Consent of Bingham Dana LLP (included in Exhibit 5).

         24       Power of Attorney (included on the signature page of this Registration Statement).
</TABLE>


ITEM 9.  UNDERTAKINGS

         (A)      The undersigned Registrant hereby undertakes:

                  (1)      To file, during any period in which offers or sales
                           are being made, a post-effective amendment to this
                           registration statement:

                           (i)    To include any prospectus required by
                                  Section 10(a)(3) of the Securities Act;

                           (ii)   To reflect in the prospectus any facts or
                                  events arising after the effective date of
                                  the registration statement (or the most
                                  recent post-effective amendment thereof)
                                  which, individually or in the aggregate,
                                  represent a fundamental change in the
                                  information set forth in the registration
                                  statement. Notwithstanding the foregoing, any
                                  increase or decrease in volume of securities
                                  offered (if the total dollar value of
                                  securities offered would not exceed that
                                  which was registered) and any deviation from
                                  the low or high and of the estimated maximum
                                  offering range may be reflected in the form
                                  of prospectus filed with the Commission
                                  pursuant to Rule 424(b) if, in the aggregate,
                                  the changes in volume and price represent no
                                  more than 20 percent change in the maximum
                                  aggregate offering price set forth in the
                                  "Calculation of Registration Fee" table in
                                  the effective registration statement.

<PAGE>


                           (iii)  To include any material information with
                                  respect to the plan of distribution not
                                  previously disclosed in the registration
                                  statement or any material change to such
                                  information in the registration statement;

                           PROVIDED, HOWEVER, that paragraphs (1)(i) and (1)(ii)
                           do not apply if the information required to be
                           included in a post-effective amendment by those
                           paragraphs is contained in periodic reports filed
                           with or furnished to the Commission by the Registrant
                           pursuant to Section 13 or Section 15(d) of the
                           Exchange Act that are incorporated by reference in
                           the registration statement.

                  (2)      That, for the purpose of determining any liability
                           under the Securities Act, each such post-effective
                           amendment shall be deemed to be a new registration
                           statement relating to the securities offered therein,
                           and the offering of such securities at that time
                           shall be deemed to be the initial BONA FIDE offering
                           thereof.

                  (3)      To remove from registration by means of a
                           post-effective amendment any of the securities being
                           registered which remain unsold at the termination of
                           the offering.

         (B)      The undersigned Registrant hereby undertakes that, for
                  purposes of determining any liability under the Securities Act
                  each filing of the Registrant's annual report pursuant to
                  Section 13(a) or Section 15(d) of the Exchange Act (and, where
                  applicable, each filing of an employee benefit plan's annual
                  report pursuant to Section 15(d) of the Exchange Act) that is
                  incorporated by reference in the registration statement shall
                  be deemed to be a new registration statement relating to the
                  securities offered therein, and the offering of such
                  securities at that time shall be deemed to be the initial BONA
                  FIDE offering thereof.

         (C)      Insofar as indemnification for liabilities arising under the
                  Securities Act may be permitted to directors, officers and
                  controlling persons of the Registrant pursuant to the
                  foregoing provisions, or otherwise, the Registrant has been
                  advised that in the opinion of the Securities and Exchange
                  Commission such indemnification is against public policy as
                  expressed in the Securities Act and is, therefore,
                  unenforceable. In the event that a claim for indemnification
                  against such liabilities (other than the payment by the
                  Registrant of expenses incurred or paid by a director, officer
                  or controlling person of the Registrant in the successful
                  defense of any action, suit or proceeding) is asserted by such
                  director, officer or controlling person in connection with the
                  securities being registered, the Registrant will, unless in
                  the opinion of its counsel the matter has been settled by
                  controlling precedent, submit to a court of appropriate
                  jurisdiction the question whether such indemnification by it
                  is against public policy as expressed in the Securities Act
                  and will be governed by the final adjudication of such issue.



<PAGE>

                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the Town of Westford, Commonwealth of Massachusetts, as of
the 18th day of January 2001.

                                   SONUS NETWORKS, INC.


                                    By: /s/ Hassan M. Ahmed
                                       ------------------------------------
                                       Hassan M. Ahmed
                                       President and Chief Executive Officer



                                POWER OF ATTORNEY

         Each person whose signature appears below hereby appoints Hassan M.
Ahmed, Stephen J. Nill, and each of them severally, his true and lawful
attorney-in-fact with the authority to execute in the name of each such person,
and to file with the Securities and Exchange Commission, together with any
exhibits thereto and other documents therewith, any and all amendments
(including without limitation post-effective amendments) to this Registration
Statement on Form S-8 necessary or advisable to enable the Registrant to comply
with the Securities Act of 1933, as amended, and any rules, regulations, and
requirements of the Securities and Exchange Commission in respect thereof, which
amendments may make such other changes in the Registration Statement as the
aforesaid attorney-in-fact executing the same deems appropriate.

         Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities indicated as of the 18th day of January 2001.


<TABLE>
<CAPTION>
         SIGNATURE                                            TITLE
         ---------                                            -----
<S>                                      <C>

/s/ Hassan M. Ahmed
---------------------------------        President, Chief Executive Officer and Director (Principal
Hassan M. Ahmed                          Executive Officer)

/s/ Stephen J. Nill
---------------------------------        Vice President of Finance and Administration and Chief Financial
Stephen J. Nill                          Officer (Principal Financial and Accounting Officer)

/s/ Rubin Gruber
---------------------------------        Chairman of the Board of Directors and Director
Rubin Gruber

/s/ Edward T. Anderson
---------------------------------        Director
Edward T. Anderson

/s/ Paul J. Ferri
---------------------------------        Director
Paul J. Ferri

/s/ Paul J. Severino
---------------------------------        Director
Paul J. Severino
</TABLE>



<PAGE>

                                  EXHIBIT INDEX


<TABLE>
<CAPTION>
EXHIBIT NO.                                 DESCRIPTION OF DOCUMENTS
-----------                                 ------------------------
<S>               <C>
         4.1      Fourth Amended and Restated Certificate of Incorporation of the Registrant,
                  incorporated by reference to Exhibit No. 3.1 to the Registrant's Registration
                  Statement on Form S-1 (file No. 333-32206).

         4.2.     Amended and Restated By-Laws of the Registrant, incorporated by reference to
                  Exhibit No. 3.2 to the Registrant's Registration Statement on Form S-1 (file No. 333-32206).

         4.3      telecom technologies, inc. Amended and Restated 1998 Equity Incentive Plan, as
                  amended, incorporated by reference to Exhibit No. 10.3 to the Registrant's
                  Registration Statement on Form S-4 (file No. 333-52682).

         4.4      Sonus Networks, Inc. 2000 Retention Plan incorporated by reference to Exhibit
                  No. 10.2 to the Registrant's Registration Statement on Form S-4 (file No. 333-52682).

         5        Opinion of Bingham Dana LLP as to the legality of the securities being registered.

         23.1     Consent of Arthur Andersen LLP, independent accountants, dated January 18, 2001.

         23.2     Consent of Arthur Andersen LLP, independent accountants, dated January 18, 2001.

         23.3     Consent of Bingham Dana LLP (included in Exhibit 5).

         24       Power of Attorney (included on the signature page of this Registration Statement).
</TABLE>
[{"type": "S-8", "sequence": "1", "filename": "a2035755zs-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 21577}]
{"company-data": {"conformed-name": "SONUS NETWORKS INC", "cik": "0001105472", "assigned-sic": "7373", "irs-number": "043387074", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-53970", "film-number": "1511639"}, "business-address": {"street1": "5 CARLISLE RD", "city": "WESTFORD", "state": "MA", "zip": "01886", "phone": "9786928999"}, "mail-address": {"street1": "5 CARLISLE RD", "city": "WESTFORD", "state": "MA", "zip": "01886"}}
As filed with the Securities and Exchange Commission on January 19, 2001.
                                                    Registration No. 333-_______
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                             ----------------------

                                    FORM S-8
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933
                             ----------------------

                              SONUS NETWORKS, INC.
             (Exact Name of Registrant as Specified in Its Charter)

                                    DELAWARE
         (State or Other Jurisdiction of Incorporation or Organization)

                                   04-3387074
                      (I.R.S. Employer Identification No.)

      5 CARLISLE ROAD, WESTFORD, MASSACHUSETTS                    01886
      (Address of Principal Executive Offices)                  (Zip Code)

                             ----------------------

   TELECOM TECHNOLOGIES, INC. AMENDED AND RESTATED 1998 EQUITY INCENTIVE PLAN

                    SONUS NETWORKS, INC. 2000 RETENTION PLAN
                            (Full Title of the Plans)

                             ----------------------

                                 HASSAN M. AHMED
                                    President
                           and Chief Executive Officer
                              Sonus Networks, Inc.
                                 5 Carlisle Road
                               Westford, MA 01886
                     (Name and Address of Agent for Service)

                                 (978) 692-8999
           Telephone Number, Including Area Code, of Agent For Service

                             ----------------------

                                    Copy to:
                              DAVID L. ENGEL, ESQ.
                             JOHAN V. BRIGHAM, ESQ.
                                BINGHAM DANA LLP
                               150 Federal Street
                           Boston, Massachusetts 02110
                                 (617) 951-8000
CALCULATION OF REGISTRATION FEE
================================================================================================================================
                                                                   Proposed          Proposed
                 Title Of                                           Maximum          Maximum
                Securities                        Amount          Offering          Aggregate                     Amount Of
                  To Be                           To Be           Price Per          Offering                   Registration
                Registered                      Registered          Share             Price                          Fee
--------------------------------------------------------------------------------------------------------------------------------
Common Stock, $0.001 par value per share
to be issued under the Equity Incentive
Plan                                            1,067,156         $0.80 (1)         $853,724.80 (1)                     $213.43
--------------------------------------------------------------------------------------------------------------------------------
                                                1,182,517         $1.00 (1)       $1,182,517.00 (1)                     $295.63
--------------------------------------------------------------------------------------------------------------------------------
                                                  37,500          $1.50 (1)          $56,250.00 (1)                      $14.06
--------------------------------------------------------------------------------------------------------------------------------
                                                 132,033          $2.00 (1)         $264,066.00 (1)                      $66.02
--------------------------------------------------------------------------------------------------------------------------------
Common Stock, $0.001 par value per share
to be issued under the 2000 Retention Plan      3,000,000       $26.938 (2)      $80,814,000.00 (2)                  $20,203.50
--------------------------------------------------------------------------------------------------------------------------------
TOTAL FEE TO BE PAID BY REGISTRANT                                                                                   $20,793.00
================================================================================================================================
(1)  Based on the maximum exercise price of the shares subject to outstanding
     options issued under the Registrant's Equity Incentive Plan. Such shares
     are issuable upon exercise of outstanding options with fixed exercise
     prices. Pursuant to Rule 457(h)(1), the aggregate offering price and the
     fee have been computed upon the basis of the price at which the options may
     be exercised. The offering price per share set forth for such shares is the
     exercise price per share at which such options are exercisable.

(2)  Pursuant to Rule 457(h)(1), the aggregate offering price and amount of the
     registration fee has been computed with respect to those shares of the
     common stock issuable under the 2000 Retention Plan that are being
     registered hereunder. For the purpose of calculating the filing fee only,
     the average high and low sale price of the Registrant's common stock as
     quoted on Nasdaq on January 16, 2001 has been used.
PART II

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents filed by Sonus Networks, Inc., file no.
000-30229, with the Securities and Exchange Commission (the "SEC") are hereby
incorporated by reference into this Registration Statement:
PERIOD
                                                                                                    ------
The description of the common stock of Sonus Networks, Inc.
           (the "Registrant"), $0.001 par value per share, contained in the
           Registrant's Registration Statement on Form 8-A pursuant to Section
           12(g) of the Securities Exchange Act....................................  Filed April 5, 2000

           Quarterly Reports on Form 10-Q..........................................  Quarters ended, June 30, 2000 and
                                                                                     September 30, 2000

           Current Reports on Form 8-K.............................................  Filed on October 13, 2000 and
                                                                                     November 17, 2000

           Prospectus filed pursuant to Rule 424(b)(1) (file no. 333-52682)......... Filed January 12, 2001
In addition, all documents filed pursuant to Sections 13(a), 13(c), 14
and 15(d) of the Exchange Act subsequent to the date of this Registration
Statement and prior to the filing of a post-effective amendment which indicates
that all securities registered hereby have been sold or which deregisters all of
such securities then remaining unsold shall be incorporated by reference into
this Registration Statement as of the filing date of each.

ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         As of January 15, 2001, 6 attorneys at Bingham Dana LLP, outside
corporate counsel for the Registrant, owned, in the aggregate, 161,781 shares of
Sonus Common Stock.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the Delaware General Corporation law empowers a Delaware
corporation to indemnify its officers and directors and certain other persons to
the extent and under the circumstances set forth therein.

         The Fourth Amended and Restated Certificate of Incorporation of the
Registrant and the Amended and Restated By-Laws of the Registrant, as amended to
date, provide for indemnification of officers and directors of the Registrant
and certain other persons against liabilities and expenses incurred by any of
them in certain stated proceedings and under certain stated conditions.

         The Registrant may maintain insurance for the benefit of its directors,
officers, employees, agents and certain other persons, insuring such persons
against any expense, liability, or loss, including liability under the
securities laws.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.
Not applicable.

ITEM 8.  EXHIBITS.

         The following exhibits are filed as part of this Registration
Statement:
EXHIBIT NO.                                 DESCRIPTION OF DOCUMENTS
-----------                                 ------------------------
4.1      Fourth Amended and Restated Certificate of Incorporation of the Registrant,
                  incorporated by reference to Exhibit No. 3.1 to the Registrant's Registration
                  Statement on Form S-1 (file No. 333-32206).

         4.2.     Amended and Restated By-Laws of the Registrant, incorporated by reference to
                  Exhibit No. 3.2 to the Registrant's Registration Statement on Form S-1 (file No. 333-32206).

         4.3      telecom technologies, inc. Amended and Restated 1998 Equity Incentive Plan, as
                  amended, incorporated by reference to Exhibit No. 10.3 to the Registrant's
                  Registration Statement on Form S-4 (file No. 333-52682).

         4.4      Sonus Networks, Inc. 2000 Retention Plan incorporated by reference to Exhibit
                  No. 10.2 to the Registrant's Registration Statement on Form S-4 (file No. 333-52682).

         5        Opinion of Bingham Dana LLP as to the legality of the securities being registered.

         23.1     Consent of Arthur Andersen LLP, independent accountants, dated January 18, 2001.

         23.2     Consent of Arthur Andersen LLP, independent accountants, dated January 18, 2001.

         23.3     Consent of Bingham Dana LLP (included in Exhibit 5).

         24       Power of Attorney (included on the signature page of this Registration Statement).
ITEM 9.  UNDERTAKINGS

         (A)      The undersigned Registrant hereby undertakes:

                  (1)      To file, during any period in which offers or sales
                           are being made, a post-effective amendment to this
                           registration statement:

                           (i)    To include any prospectus required by
                                  Section 10(a)(3) of the Securities Act;

                           (ii)   To reflect in the prospectus any facts or
                                  events arising after the effective date of
                                  the registration statement (or the most
                                  recent post-effective amendment thereof)
                                  which, individually or in the aggregate,
                                  represent a fundamental change in the
                                  information set forth in the registration
                                  statement. Notwithstanding the foregoing, any
                                  increase or decrease in volume of securities
                                  offered (if the total dollar value of
                                  securities offered would not exceed that
                                  which was registered) and any deviation from
                                  the low or high and of the estimated maximum
                                  offering range may be reflected in the form
                                  of prospectus filed with the Commission
                                  pursuant to Rule 424(b) if, in the aggregate,
                                  the changes in volume and price represent no
                                  more than 20 percent change in the maximum
                                  aggregate offering price set forth in the
                                  "Calculation of Registration Fee" table in
                                  the effective registration statement.
(iii)  To include any material information with
                                  respect to the plan of distribution not
                                  previously disclosed in the registration
                                  statement or any material change to such
                                  information in the registration statement;

                           PROVIDED, HOWEVER, that paragraphs (1)(i) and (1)(ii)
                           do not apply if the information required to be
                           included in a post-effective amendment by those
                           paragraphs is contained in periodic reports filed
                           with or furnished to the Commission by the Registrant
                           pursuant to Section 13 or Section 15(d) of the
                           Exchange Act that are incorporated by reference in
                           the registration statement.

                  (2)      That, for the purpose of determining any liability
                           under the Securities Act, each such post-effective
                           amendment shall be deemed to be a new registration
                           statement relating to the securities offered therein,
                           and the offering of such securities at that time
                           shall be deemed to be the initial BONA FIDE offering
                           thereof.

                  (3)      To remove from registration by means of a
                           post-effective amendment any of the securities being
                           registered which remain unsold at the termination of
                           the offering.

         (B)      The undersigned Registrant hereby undertakes that, for
                  purposes of determining any liability under the Securities Act
                  each filing of the Registrant's annual report pursuant to
                  Section 13(a) or Section 15(d) of the Exchange Act (and, where
                  applicable, each filing of an employee benefit plan's annual
                  report pursuant to Section 15(d) of the Exchange Act) that is
                  incorporated by reference in the registration statement shall
                  be deemed to be a new registration statement relating to the
                  securities offered therein, and the offering of such
                  securities at that time shall be deemed to be the initial BONA
                  FIDE offering thereof.

         (C)      Insofar as indemnification for liabilities arising under the
                  Securities Act may be permitted to directors, officers and
                  controlling persons of the Registrant pursuant to the
                  foregoing provisions, or otherwise, the Registrant has been
                  advised that in the opinion of the Securities and Exchange
                  Commission such indemnification is against public policy as
                  expressed in the Securities Act and is, therefore,
                  unenforceable. In the event that a claim for indemnification
                  against such liabilities (other than the payment by the
                  Registrant of expenses incurred or paid by a director, officer
                  or controlling person of the Registrant in the successful
                  defense of any action, suit or proceeding) is asserted by such
                  director, officer or controlling person in connection with the
                  securities being registered, the Registrant will, unless in
                  the opinion of its counsel the matter has been settled by
                  controlling precedent, submit to a court of appropriate
                  jurisdiction the question whether such indemnification by it
                  is against public policy as expressed in the Securities Act
                  and will be governed by the final adjudication of such issue.
SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the Town of Westford, Commonwealth of Massachusetts, as of
the 18th day of January 2001.

                                   SONUS NETWORKS, INC.

                                    By: /s/ Hassan M. Ahmed
                                       ------------------------------------
                                       Hassan M. Ahmed
                                       President and Chief Executive Officer

                                POWER OF ATTORNEY

         Each person whose signature appears below hereby appoints Hassan M.
Ahmed, Stephen J. Nill, and each of them severally, his true and lawful
attorney-in-fact with the authority to execute in the name of each such person,
and to file with the Securities and Exchange Commission, together with any
exhibits thereto and other documents therewith, any and all amendments
(including without limitation post-effective amendments) to this Registration
Statement on Form S-8 necessary or advisable to enable the Registrant to comply
with the Securities Act of 1933, as amended, and any rules, regulations, and
requirements of the Securities and Exchange Commission in respect thereof, which
amendments may make such other changes in the Registration Statement as the
aforesaid attorney-in-fact executing the same deems appropriate.

         Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities indicated as of the 18th day of January 2001.
SIGNATURE                                            TITLE
         ---------                                            -----
/s/ Hassan M. Ahmed
---------------------------------        President, Chief Executive Officer and Director (Principal
Hassan M. Ahmed                          Executive Officer)

/s/ Stephen J. Nill
---------------------------------        Vice President of Finance and Administration and Chief Financial
Stephen J. Nill                          Officer (Principal Financial and Accounting Officer)

/s/ Rubin Gruber
---------------------------------        Chairman of the Board of Directors and Director
Rubin Gruber

/s/ Edward T. Anderson
---------------------------------        Director
Edward T. Anderson

/s/ Paul J. Ferri
---------------------------------        Director
Paul J. Ferri

/s/ Paul J. Severino
---------------------------------        Director
Paul J. Severino
EXHIBIT INDEX
EXHIBIT NO.                                 DESCRIPTION OF DOCUMENTS
-----------                                 ------------------------
4.1      Fourth Amended and Restated Certificate of Incorporation of the Registrant,
                  incorporated by reference to Exhibit No. 3.1 to the Registrant's Registration
                  Statement on Form S-1 (file No. 333-32206).

         4.2.     Amended and Restated By-Laws of the Registrant, incorporated by reference to
                  Exhibit No. 3.2 to the Registrant's Registration Statement on Form S-1 (file No. 333-32206).

         4.3      telecom technologies, inc. Amended and Restated 1998 Equity Incentive Plan, as
                  amended, incorporated by reference to Exhibit No. 10.3 to the Registrant's
                  Registration Statement on Form S-4 (file No. 333-52682).

         4.4      Sonus Networks, Inc. 2000 Retention Plan incorporated by reference to Exhibit
                  No. 10.2 to the Registrant's Registration Statement on Form S-4 (file No. 333-52682).

         5        Opinion of Bingham Dana LLP as to the legality of the securities being registered.

         23.1     Consent of Arthur Andersen LLP, independent accountants, dated January 18, 2001.

         23.2     Consent of Arthur Andersen LLP, independent accountants, dated January 18, 2001.

         23.3     Consent of Bingham Dana LLP (included in Exhibit 5).

         24       Power of Attorney (included on the signature page of this Registration Statement).