Low-Cost, High-Capacity, Feature-Rich IPX Solution for Interconnect Providers

Westford, Mass., May 25, 2011 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in next-generation IP-based network solutions , today announced the availability of an IP Packet Exchange (IPX) solution for fixed and mobile networks. The Sonus solution supports IPX features defined by industry organizations such as i3Forum and GSMA, along with session-aware value-added features that Sonus has defined. These features fall into three broad categories: signaling interworking, media transcoding and centralized routing and policy.

This solution leverages the common software base of Sonus's SBC9000™ and SBC5200™ session border controllers, which form its core. The SBC products are complemented by the Sonus Network Analytics Suite, which actively monitors the customer's quality of experience, and the PSX™ Centralized Routing and Policy Server that supports intelligent policy-based routing. Sonus's SBC family of session border controllers provide robust session control, media transcoding and security for both legacy networks in transition and the next generation of pure IP communications. Both the SBC5200 and SBC9000 have received Performance Verified Certification from Miercom Labs to deliver extraordinary performance even under the most adverse of conditions.

As mobile operators start to deploy 4G LTE networks, service-aware IPX service will play an increasingly important role in enabling roaming. Similarly, in fixed networks, the migration from TDM to IP will increase the need for service-aware IPX capability.

"BICS is constantly seeking to remain at the forefront and is offering its customers a feature-rich IPX solution," said Pierre-André Rulmont, CTO of BICS a Belgacom company. "It is therefore important for us to be able to count upon a good supplier for the underlying technology, which Sonus has proven to be. We are very pleased with the overall functionalities as well as the performance results of the Sonus IPX solution running on the SBC family of session border controllers."

The Sonus IPX solution delivers the functionality that Interconnect Providers need to maximize the benefits of their IPX deployment: robust security, efficient QoS control, SLA-based call admission control, and CDR generation. Additional IPX features supported include a range of signaling interworking, wireline, wireless, and high-definition (HD) media transcoding, 3GPP standards conformance, IPV4/IPV6 transport and services interworking, robust overload handling, and enhanced routing. The Sonus solution allows IPX Providers to offer ENUM services.

"The value-added features in our SBC products go well beyond the connectivity and security offered by a stand-alone SBC," said David Tipping, vice president of product management and marketing at Sonus. "The IPX solution is an example of how the inherent capabilities of our SBC can be utilized to provide additional value to the customer."

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 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' 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

Paul Roberts
sonus@daviesmurphy.com
+1 781-418-2418