Sonus Networks Announces Industry's First Voice Protection Capability And Enhances The Market-Leading SBC

VoiceSentry Lowers Call Center Costs by Protecting Voice Networks from Telephony Denial-of-Service Attacks in Real Time

Westford, Mass., February 1, 2011 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in next-generation IP-based network solutions , today announced the general availability of VoiceSentry™ an application-aware security system that protects Call Centers against telephony Denial of Service and other voice attacks. Telephony Denial of Service (T-DoS) has grown so quickly that the Federal Bureau of Investigation now tracks it separately from Internet DoS and Distributed Denial of Service (DDoS).

The VoiceSentry system gives enterprises a way to safeguard their voice networks from new cyber threats and keep enterprise costs from escalating. This innovative new solution extends the capabilities of the Sonus NBS5200 Session Border Controller to a new area of voice security .

"Half of remote customer interaction still takes place via telephone and every bad experience, whether from long wait times or blocked access, represents lost revenue for the call center," said Mykola Konrad, director of enterprise products at Sonus. "Customer satisfaction degrades with each minute on hold and 40percent of abandoned callers do not call back. Voice Sentry gives calls centers their first line of defense for protecting their assets, their profitability, and their reputation."

"Advances in IP technology have opened up voice-based operations such as call centers to new voice attacks for which they haven't had a good defense mechanism," said Elisabeth Rainge, director of NGN operations at IDC. "The potential impact on the call center's operations is significant: their costs could increase as they struggle to handle the enormous volume of fraudulent calls, customer satisfaction could drop as response time slows, and the company's brand could take a hit."

Sonus will demonstrate its new VoiceSentry System in Booth 364 at IT Expo East, running from February 2 to 4 in the Miami Beach Convention Center.

The Sonus VoiceSentry System

Sonus' VoiceSentry system provides a holistic approach to protecting call centers. The software builds on the successful Sonus NBS5200 Session Border Controller and extends its functionality to the application level of the OSI model by providing application-aware voice security. It is comprised of two hardware elements - the VoiceSentry Analyzer and the VoiceSentry Guardian.

The VoiceSentry system's patent-pending Analyzer function uses call-signature analysis to detect voice spam and T-DoS attacks. It diverts a suspicious call to the VoiceSentry Guardian - an innovative audio- CAPTCHA system. Depending on the test results, the VoiceSentry Analyzer can disconnect the call or route it to another destination. Telephony network managers gain network-wide situational awareness though a dashboard with an alarm center, visual reporting, and historical analysis. The VoiceSentry system learns and adapts to the enterprise-specific calling patterns.

The Voice Sentry security system is generally available today. For more information, go to /Products/Voice-Security-Systems.aspx

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: .

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, 2009 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:

Aline Kaplan
alkaplan@sonusnet.com
+1 978-614-8167

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