Peerless Network to Deploy Sonus NBS5200 for Advanced Session Border Control

Service Provider Selects Product for Its Industry-Leading Performance, Scalability, and Transcoding Density

WESTFORD, Mass., November 30, 2010 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in next-generation IP-based network solutions , today announced that Peerless Network, a service provider that simplifies interconnection of voice, data and signaling across disparate networks, has purchased the Sonus NBS5200 TM Network Border Switch to expand the capacity of its IP peering aggregation points.

Built on Sonus's new ConnexIP™ platform, the NBS5200 represents the next generation in border control with unmatched functionality. It is the highest-density, highest-scalability Session Border Control (SBC) solution in its class with integrated transcoding and media interworking as well as native support for IPv6 and IPSec encryption.

Peerless Network added the NBS5200 to its existing NBS9000 TM deployment because of the product's scalability and network capacity performance as well as its minimal footprint requirements in the data center. Peerless Network has experienced tremendous growth in IP traffic and selected the NBS5200 based upon its industry-leading performance, on-board transcoding, and network integration characteristics. With the ConnexIP platform, it provides high-performance network services in an extremely compact footprint that reduces operations and data center costs.

"We have completed our certification process on the NBS5200 and are very pleased with its overall functionality and performance results," said Jim Brewer, Vice President of Voice Services for Peerless Network. "We look forward to meeting the requirements of our rapidly expanding customer base and service portfolio with the deployment of this strategic IP platform at Peerless."

Independent testing firm Miercom Labs recently evaluated the NBS5200 and awarded the session border controller its Performance Verified Certification Miercom's extensive testing concluded that Sonus's NBS5200 delivers extraordinary performance even under the most adverse conditions where other products often exhibit significant performance breakdown.

The NBS5200 enables Sonus to address the broadest set of SBC deployments in the market for service providers and enterprises. It has created strong customer interest since its introduction. In addition to its current customers, the NBS5200 is in trials and evaluations at multiple other locations.

"The NBS5200 will help Peerless Network to leverage its existing Sonus network and pave the way to handle future demands," said Guru Pai, executive vice president and chief operating officer for Sonus. "Their decision demonstrates the market demand for a high session scale, transcoding dense-session, border controller solution. With it, they save on capital and operational expenses, which increases their return on IP infrastructure investments and makes the deployment more flexible."

About the Sonus NBS5200

Launched earlier this year, the Sonus NBS5200 is a next-generation session border control product and the first Sonus product launched on the ConnexIP platform. It employs the latest generation of network processors, computing processors and digital signal processors (DSPs) to deliver the highest performance-density SBC on the market. Its functions include integrated transcoding, media interworking and native support for addressing IPv6.

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.

About Peerless Network, Inc.

Peerless is a privately held company focused on simplifying the interconnection process for other telecommunications service providers and end users alike. Peerless provides a broad range of services, with reliable and cost-effective solutions to seamlessly access myriad networks regardless of protocols, traffic types or regulatory status. Based in Chicago, the company currently offers services in Chicago, New York, Philadelphia, Connecticut, Miami, Atlanta, San Francisco, New Jersey, Minneapolis, Los Angeles, San Diego, St. Louis, Tampa, Orlando, Columbus, Indianapolis, Milwaukee, and numerous Tier II and Tier III markets. More information is available at www.peerlessnetwork.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, 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