Deployment Will Enable Independent Carrier to Interconnect with State-Owned Incumbent Operator

WESTFORD, Mass., November 9, 2010 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in next-generation IP-based network solutions , today announced that American Data Networks, one of the first telecommunications providers to offer services in the newly deregulated Costa Rican market, will deploy a new Class 4 trunking solution based on the Sonus GSX9000. Other Sonus equipment used in the deployment includes the PSX Centralized Route Server, Element Management System (EMS), DataStream Integrator (DSI) and International Gateway with SS7 interconnection capability.

With more than 60 carriers granted operating licenses in the newly deregulated Costa Rican telecommunications market, American Data Networks is one of the first operators to begin offering services under the new rules, and the first company in the country to use a Sonus switch. A key to success in this competitive environment is seamlessly and securely interconnecting with Instituto Costarricense de Electricidad (ICE), the state-owned incumbent operator, to provide long distance services to ICE subscribers. By deploying the Sonus solution, American Data Networks has not only gained significant capacity for VoIP peering with partners in the United States, but is also in a strong position compared to all other providers.

"The deployment of Sonus equipment is an integral component of American Data Networks' strategy of becoming a leading provider of telecommunications services in Costa Rica's recently deregulated market," said Arturo Saenz, General Manager of American Data Networks. "Sonus is widely recognized and respected by many of the leading carriers around the world and the relative ease of deployment and migration from our legacy system has significantly accelerated our time to market."

Ultimately, American Data Networks will benefit from the operational simplification offered by Sonus equipment. In a rapidly evolving market, capabilities for both PSX Centralized Routing and Centralized Provisioning have become requirements for scaling beyond the limitations inherent in the operator's former solution, which relied on a full-mesh static configuration at the gateway level.

Sonus, via SS7 interconnection, is helping to fulfill an additional requirement for interconnection among carriers as the Costa Rican market continues along the path of deregulation. American Data Networks had found that its former solution was not able to do so natively.

"The increasingly competitive nature of the Costa Rican telecommunications market provides great opportunity, but also introduces very real challenges to the service providers that are operating there," said Steve Collins, Vice President of Americas Sales and Corporate Sales Strategy, Sonus Networks. "Sonus products offer operators such as American Data Networks a compelling value proposition and the means to effectively build out their networks to meet both customer and business requirements."

About American Data Networks

American Data Networks is specialized in telecommunications services of the highest quality. The company has developed the international and national infrastructure, and the technology platform and customer service that guarantees it. American Data provides Internet services, VoIP services, point-to-point private networks, datacenter colocation services, and network management to its Costa Rican customers.

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, 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:

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

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