Sonus Networks Experiencing Rapid Growth in Session Border Controller Market

WESTFORD, Mass., December 14 - Sonus Networks, Inc. (Nasdaq: SONS), a market leader in next-generation IP-based network solutions, today announced that it has achieved the largest quarterly market share gain and revenue growth in the Session Border Controller (SBC) business as reported by Infonetics Research in its recent Service Provider VoIP Equipment and Subscribers 3Q11report.  

Sonus solidified its position as one of the leading vendors in the SBC market with product revenues that grew an industry-leading 35.6 percent quarter-over-quarter and 232.7 percent from the same quarter a year ago. The company's SBC market share also grew to 13.9 percent, up nearly five percentage points from last quarter and more than nine percentage points from a year ago.

"Our third quarter analysis shows that Sonus is experiencing solid growth and distinguishing itself as a vendor to watch in the SBC space," said Diane Myers, directing analyst for VoIP and IMS at Infonetics Research . "While product testing and acceptance comprises a long cycle with service providers, Sonus has been moving ahead steadily with its SBC product portfolio including the NBS9000TM and NBS5200TM over the past year."

The Infonetics report also notes that, "the growth of VoIP subscribers in fixed and mobile networks, SIP trunking, and IP interconnectivity will continue to be important drivers for SBCs," emphasizing key areas of strength for Sonus as it expands its SBC footprint with new and existing customers.

This report is the latest in a series of market validations that Sonus has received as an enabler of SIP applications and services. A similar report issued by Exact Ventures in November also shows that Sonus is one of the top two vendors in the SBC space. In July, the NBS5200 received the 2010 Communications Solutions Product of the Year award for its outstanding innovation and in March, the NBS5200 and NBS 9000 session border controllers received the Performance Verified Award from Miercom .

"More and more customers are trusting Sonus to deliver the most advanced SBC products that offer great flexibility and the best performance under real-world conditions," said David Tipping, vice president and general manager of Session Border Controllers at Sonus Networks. "These independent reports underscore that Sonus' networked approach enables the advanced SIP applications and features that enterprise and service provider markets are looking for in a next-generation SBC solution."

About Sonus Session Border Controllers

The Sonus NBS5200 and NBS9000 session border controllers offer a wide range of features that help service providers and enterprises to reduce expenses and increase revenue by improving security, delivering a consistently high quality of experience to customers, scaling up without building a complex infrastructure, and migrating to SIP on their own schedule. They provide advanced media services such as onboard transcoding and support a range of traditional wireline codecs that can increase to tens of thousands of sessions. In combination with the Sonus PSX™ centralized routing and policy server, they provide a unique networked view of routing and policy management that simplifies operations to run more efficiently, lowers operations expenses, and assures high service levels.

About Sonus Networks

Sonus Networks, Inc. is a leader in IP networking with proven expertise in delivering secure, reliable and scalable next-generation infrastructure and subscriber solutions. With customers in over 50 countries across the globe and over a decade of experience in transforming networks to IP, Sonus has enabled service providers and enterprises to capture and retain users and generate significant ROI. Sonus products include media and signaling gateways, policy/routing servers, session border controllers and subscriber feature servers. Sonus products are supported by a global services team with experience in design, deployment and maintenance of some of the world's largest and most complex IP networks.For more information visit  and the Sonus blog.

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' Annual Report on Form 10-K for the year ended December 31, 2010 and all subsequent Quarterly Reports on Form 10-Q, which identify important risk factors that could cause actual results to differ from those contained in the forward-looking statements. 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.

For more information, please contact:

Sonus Networks:

Aline Kaplan
alkaplan@sonusnet.com
+1 978-614-8167
Patti Leahy
Investor Relations
pleahy@sonusnet.com
+1 978-614-8440
Paul Roberts
sonus@daviesmurphy.com
+1 781-418-2418