Successful Interoperability Testing Delivers Choice To Operators To Run Queries Over IP-Based Networks

WESTFORD, Mass., July 10, 2008 /PRNewswire-FirstCall via COMTEX News Network/ -- Sonus Networks
(Nasdaq: SONS), a market leader in IP communications infrastructure, today
announced that VeriSign, the trusted provider of Internet infrastructure
services for the networked world, has successfully demonstrated
interoperability testing that will allow wireless, wireline and cable
operators the ability to run number portability queries over IP-based
networks.

The introduction of number portability regulation by many governments has,
in some cases, increased the resources needed by carriers to complete the
accurate transfer of calls. The implementation of Local Number Portability
(LNP) has created the need for carriers to perform a LNP Query. This in turn
has resulted in an elevated use of the carrier's SS7 networks, and in some
cases necessitates the need to purchase additional SS7 network capacity.

"Minimizing cost continues to be a driving force behind the migration to
IP," said Paul Florack, vice president of network and database services,
VeriSign Communications Services Division. "Use of the VeriSign(R) Number
Identity Registry for real-time location routing number discovery leverages
our ENUM infrastructure, and its complete, up-to-date, portability-corrected
record of the entire North American Number Plan (NANP)."

Sonus has implemented an IP-based LNP Query mechanism, ENUM-LNP, as an
inexpensive alternative to the traditional SS7-based LNP Query. The IP
transported LNP Query is served by the VeriSign Number Identity Registry.

"Historically, number portability queries were taking place on traditional
networks, increasing resources required to fulfill the process," commented
Vikram Saksena, CTO at Sonus Networks. "By eliminating the need for legacy SS7
Service Control Points and related signaling interfaces, Sonus solutions can
reduce operational costs associated with number portability implementations.
We added this functionality in the most recent release of the Sonus multimedia
platform and we are pleased to announce interoperability with VeriSign to
enable more carriers to leverage one solution to manage their entire network,
both legacy and IP-based."

Sonus' complete Local and Mobile Number Portability solutions, which are
currently deployed in North America, Europe and Asia, support a variety of
number portability routing methods, including traditional SS7 TCAP/INAP
(Transactional Capabilities Application Part/Intelligent Network Application
Part), ENUM, or direct hosting of a local number portability routing database.

About VeriSign

VeriSign, Inc. (Nasdaq: VRSN) is the trusted provider of Internet
infrastructure services for the networked world. Billions of times each day,
VeriSign helps companies and consumers all over the world engage in
communications and commerce with confidence. Additional news and information
about the company is available at www.verisign.com.

About Sonus Networks

Sonus Networks, Inc. is a market leader in IP communications
infrastructure 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 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 March
31, 2008, 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 and patent 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, except as
required by law.

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.

VeriSign, the VeriSign logo, the checkmark circle, and other trademarks,
service marks, and designs are registered or unregistered trademarks of
VeriSign, Inc., and its subsidiaries in the United States and in foreign
countries. All other trademarks are property of their respective owners.

    For more information, please contact:

    Media Relations:                         Racepoint For Sonus:
    Lucy Millington                          Danielle Stead
    978-614-8240                             781-487-4615
    lmillington@sonusnet.com                 sonus@racepointgroup.com

SOURCE Sonus Networks, Inc.

http://www.sonusnet.com

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