WASHINGTON, D.C. 20549


                                    FORM 8-K

                                 CURRENT REPORT

     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

        Date of Report (Date of earliest event reported) August 19, 2005


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

       DELAWARE                       000-30229                 04-3387074
       --------                       ----------                ----------
(State or Other Jurisdiction    (Commission File Number)      (IRS Employer
  of Incorporation)                                         Identification No.)

             250 APOLLO DRIVE, CHELMSFORD, MASSACHUSETTS         01824
- -------------------------------------------------------------------------------
               (Address of Principal Executive Offices)        (Zip Code)

                                 (978) 614-8100
              (Registrant's telephone number, including area code)


Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

|_|  Written  communications  pursuant to Rule 425 under the  Securities Act (17
     CFR 230.425)

|_|  Soliciting  material pursuant to Rule 14a-12 under the Exchange Act (17 CFR

|_|  Pre-commencement   communications  pursuant  to  Rule  14d-2(b)  under  the
     Exchange Act (17 CFR 240.14d-2(b))

|_|  Pre-commencement   communications  pursuant  to  Rule  13e-4(c)  under  the
     Exchange Act (17 CFR 240.13e-4(c))

Item 5.02(b). Departure of Directors or Principal Officers; Election of Directors; Appointment of Principal Officers. On August 19, 2005, Sonus Networks, Inc. was notified that Rubin Gruber is retiring from the Company's Board of Directors effective August 31, 2005.

SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Date: August 23, 2005 SONUS NETWORKS, INC. By: /s/ Ellen Richstone ---------------------------------- Ellen Richstone Chief Financial Officer

                                                                    Exhibit 99.1

    Rubin Gruber to Retire from Sonus Networks' Board of Directors

    CHELMSFORD, Mass.--(BUSINESS WIRE)--Aug. 23, 2005--Sonus Networks
(Nasdaq: SONS), a leading supplier of service provider voice over IP
(VoIP) infrastructure solutions, today announced that its Chairman
Emeritus, Rubin Gruber, will be retiring from the Sonus Networks Board
of Directors at the end of August. Mr. Gruber has served on Sonus
Networks' Board of Directors since co-founding the company in 1997 and
he will continue to be available to assist the Company.
    "During the last eight years, I have had the unique opportunity to
experience Sonus' growth from an idea into a global leader in the VoIP
market," commented Rubin Gruber. "Sonus has achieved a great deal
since its founding, and I remain excited about Sonus' prospects as a
leader in the VoIP industry."
    "As co-founder and a member of our senior management team, Rubin's
business acumen, industry experience, and his unwavering commitment to
building Sonus into a recognized leader in the market has been a great
benefit to Sonus," said Hassan Ahmed, chairman and CEO, Sonus
Networks. "Rubin is one of the true pioneers in our industry. Although
I will personally miss his presence in the Boardroom, I share his
enthusiasm for Sonus' future and look forward to building on the
Company's leadership position."
    Following Mr. Gruber's retirement, the Sonus Networks Board of
Directors will consist of the following members: Hassan Ahmed, Bert
Notini, Ed Anderson, Paul Severino, H. Brian Thompson and John

    About Sonus Networks

    Sonus Networks, Inc. is a leading provider of voice over IP (VoIP)
infrastructure solutions for wireline and wireless service providers.
With its comprehensive IP Multimedia Subsystem (IMS) solution, Sonus
addresses the full range of carrier applications, including
residential and business voice services, wireless voice and
multimedia, trunking and tandem switching, carrier interconnection and
enhanced services. Sonus' voice infrastructure solutions are deployed
in service provider networks worldwide. Founded in 1997, Sonus is
headquartered in Chelmsford, Massachusetts. Additional information on
Sonus is available at http://www.sonusnet.com.

    This release may contain forward-looking statements regarding
future events that involve risks and uncertainties. Readers are
cautioned that these forward-looking statements are only predictions
and may differ materially from actual future events or results.
Readers are referred to the "Risk Factors" section of Sonus' Annual
Report on Form 10-K, dated March 15, 2005, and the "Cautionary
Statements" section of Sonus' Quarterly Report on Form 10-Q, dated
August 8, 2005, both filed with the SEC, which identify important risk
factors that could cause actual results to differ from those contained
in the forward-looking statements. Risk factors include among others:
the impact of material weaknesses in our disclosure controls and
procedures and our internal control over financial reporting on our
ability to report our financial results timely and accurately; the
unpredictability of our quarterly financial results; risks associated
with our international expansion and growth; consolidation in the
telecommunications industry; and potential costs resulting from
pending securities litigation against the company. Any forward-looking
statements represent Sonus' views only as of today and should not be
relied upon as representing Sonus' views as of any subsequent date.
While Sonus may elect to update forward-looking statements at some
point, Sonus specifically disclaims any obligation to do so.

    Sonus is a registered trademark of Sonus Networks. Open Services
Architecture is a trademark of Sonus Networks. All other company and
product names may be trademarks of the respective companies with which
they are associated.

    CONTACT: Sonus Networks, Inc.
             Investor Relations:
             Jocelyn Philbrook, 978-614-8672
             Media Relations:
             Sarah McAuley, 212-699-1836