KPN Subsidiary Newtel Essence Selects Sonus NBS5200 and GSX9000 as Backbone of Enterprise Offering

WESTFORD, Mass., March 30, 2011 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in next-generation IP-based network solutions , today announced that Newtel Essence, a wholly owned subsidiary of KPN, has selected the NBS5200™ and GSX9000™ as the backbone of its enterprise offering.

Newtel Essence is a Netherlands-based KPN subsidiary focused on delivering innovative services and added-value offerings to enterprises. Newtel Essence is the enterprise arm of KPN, The leading telecommunications, Internet, TV and ICT service provider in the Netherlands.

"We selected the Sonus solution because, like our customers, we require a network that allows convergence to an all-IP network on our terms. Sonus was the best vendor that offered a hybrid TDM-to-IP and IP-to-IP based solution, taking into account the business needs of Newtel Essence, which was critical in winning the recent contract with the government of The Netherlands," said Nico Bettings, managing director of Newtel Essence.

Built on Sonus' new ConnexIP™ platform, the NBS5200 represents the next generation in border control. 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. It combines full SBC functionality that includes media interworking, an advanced routing and policy engine, and multi-access security gateway functionality, all in one second-generation SBC product without compromising scale or density.

"Sales to leading providers like KPN's Newtel Essence and large deployments by organizations such as the government of The Netherlands go a long way to validating our TDM-to-IP migration strategy," said Adrian Patterson, vice president of European sales at Sonus Networks. "This deal further illustrates the growing global interest in the NBS5200 Network Border Switch. As organizations take a strategic and measured approach to TDM-to-IP migration, Sonus continues to stand out with a complete solution portfolio that includes hybrid trunking and session border control."

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.

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