BARCELONA, Spain and WESTFORD, Massachusetts, February 13 /PRNewswire/ --

- Next-Generation Leader Increases Functionality for Business Services & 
Wireless Networks

Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service
provider IP-voice infrastructure solutions, today announced the latest
release of its industry-leading software platform. Sonus Release 7.1 delivers
a new level of IP-voice capabilities, further leveraging Sonus' field-proven
distributed architecture for growth markets such as wireless, business
services and emerging geographies.

Sonus Release 7.1 solves many of the challenges for operators in Eastern
Europe, Russia and Southeast Asia through signaling and regulatory support
that these operators must deliver, including local number portability and
lawful intercept enhancements. This latest software platform reduces capital
and operating costs with new voice codec support to efficiently combine
mobile and fixed line traffic.

"Sonus' complete portfolio of solutions is already enabling the world's
largest service providers to transform their networks. Sonus' latest
enhancements give service providers across the globe the tools required to
create new and innovative solutions, enabling them to redefine the services
and business models they offer end-users," said Hassan Ahmed, Chairman,
President and CEO of Sonus Networks. "This same Sonus portfolio delivers
services across rapidly growing WiMAX networks; providing access in emerging
markets that were traditionally underserved. Wired or wireless, Sonus
continues to create opportunities for operational improvements in provider's
networks worldwide, making the delivery of their solutions more cost
effective."

The new Sonus Release 7.1 suite includes over 100 enhancements to its IP
wireline and wireless solutions, including:

-- Integrated EFR (Enhanced Full Rate) and AMR (Adaptive Multi-Rate)
       vocoder functions to support global wireless traffic patterns;
    -- Robust additions to business services capabilities to better support
       SIP phones and IADs;
    -- Number portability compliance solutions featuring ENUM support & INAP
       additions;
    -- 83% density improvements in transcoding;
    -- IMS/3GPP R7-compliant solutions that allow carriers in emerging
       countries to deploy advanced services for WiMAX and broadband 
       Next-Gen Networks.

Leveraging Sonus' experience with millions of residential users, Sonus'
Release 7.1 enhances business customers' capabilities to connect industry
standard SIP phones and IADs to a service provider's network. Business
customers gain enhanced access to PBX-type features while saving thousands of
dollars in upfront investment. Traditional premise-based PBX equipment can
also be connected with Sonus' SIP-based IP Business Trunks. Sonus solutions
allow business users to move calls seamlessly between locations or between
wired and mobile devices.

"Operators seek to invest in flexible platforms which can support a range
of services, most importantly voice today but migrating to a full range of
multimedia services over IP over time," said Brian Partridge, Enabling
Technologies Program Manager with Yankee Group. "Sonus is well positioned to
help customers accelerate this migration to IP-voice globally while providing
investment protection for future service offerings."

Sonus Release 7.1 is available now with new product shipments and as a
software upgrade for customers with SonusCARE(SM) support and service
contracts.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of IP voice network solutions
for wireline, wireless and cable providers. Sonus' IP Multimedia Subsystem
(IMS) solution addresses the full range of carrier applications: residential
and business voice services, wireless voice and multimedia, trunking and
tandem switching, carrier interconnection and enhanced services. Sonus' voice
solutions are deployed in service provider networks worldwide. Founded in
1997, Sonus is headquartered in Westford, 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 Item 1A "Risk
Factors" of Sonus' Quarterly Report on Form 10-Q for the period ended
September 30, 2007, filed with the SEC, which identifies 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 and uncertainties associated with the
Company's restatement of its historical stock option granting practices and
accounting including regulatory actions or litigation; 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, Inc. All other company
and product names may be trademarks of the respective companies with which
they are associated.

For more information, please contact:

    U.S. Media Relations:
    Lucy Millington
    +1-978-614-8240
    lmillington@sonusnet.com

    Investor Relations:
    Jocelyn Philbrook
    +1-978-614-8672
    jphilbrook@sonusnet.com

    EMEA Media Relations:
    Paula Lender-Swain
    +44-(0)-1793-601453
    plender-swain@sonusnet.com

Web site: http://www.sonusnet.com