Sonus Networks to migrate Tata Communications' global voice network

MUMBAI, India and WESTFORD, Mass., May 12, 2008 – Tata Communications (NYSE:TCL), a leading provider of a new world of communications, and Sonus Networks, Inc. (Nasdaq: SONS), a market leader in IP communications infrastructure, unveiled plans today for the strategic expansion of Tata Communications' global voice network. The expansion of Tata Communications' global voice network represents further execution of the Company's mission to expand its global reach and ability to deliver IP-leveraged communications solutions to businesses and consumers worldwide. In addition, Tata Communications will deploy Sonus' Network Border Switch to interconnect its disparate voice networks and deliver seamless IP services across geographies.

"When undertaking international deployments of this scale, we need a partner who really understands our business goals," said John Hayduk, Chief Technology Officer, Tata Communications. "We have selected Sonus' complete fixed-line trunking solution to provide its IP-voice services in nine cities across three continents, delivering a robust, highly scalable, reliable platform for IP-voice and multimedia services. Sonus has helped Tata Communications build an extensive migration plan."

"With our forward thinking tradition, Tata Communications is preparing tomorrow's voice solutions, today", said Michel Guyot, President Global Voice Solutions for Tata Communications. "The new roll out of our IMS compliant NGN as well as our rich VoIP and IP heritage enables us to utilize our assets, vision and experience to offer service providers various options to overcome the increasing challenges that technology and innovation trends present."

Tata Communications' customer base includes more than 1,500 global carriers, 600 mobile operators, 10,000 enterprises, over 500,000 broadband and internet subscribers and around 300 Wi-Fi public hotspots, all of which demand the highest level of quality and reliability. The network will be made up of the GSX9000™ Open Services Switch, PSX™ Call Routing Server, SGX™ Signaling Gateway, the Sonus Insight™ Management System, as well as Sonus' Network Border Switch (NBS) for enhanced security and advanced peering capabilities.

"Tata Communications' global voice network connects people through one of the largest cross-border, trans-oceanic networks in the world, and we're proud that Sonus has been chosen as the foundation for its next generation network," said Hassan Ahmed, President, Chairman, and CEO Sonus Networks. "We are committed to providing interoperable and flexible solutions from the core to the edge, to meet individual customer needs. One size does not necessarily fit all on the path to an IP-voice network. We are helping customers build their networks today, to provide the competitive services of tomorrow."

Tata Communications is implementing Sonus' IMX™ Multimedia Platform for the development of enhanced business applications for its customers. The IMX platform allows for the rapid creation of new voice, video, data and other multimedia applications, as well as the integration of and support for disparate end user devices. The IMX will be employed by Tata Communications in the creation of new enterprise services that blend mobile content, location-based services, and other multimedia functionality.

Tata Communications will work with Sonus' services team to facilitate the migration from its legacy network onto the new IP-based network. Initial deployment cities include Newark, New Jersey; Montreal, Quebec; Toronto, Ontario; Los Angeles, California; London, England; Madrid, Spain; Frankfurt, Germany; and Singapore.

About Sonus Networks

Sonus Networks, Inc. is a market leader in IP communications infrastructure for wireline and wireless service providers. With its comprehensive IP Multimedia Subsystem (IMS) solution, Sonus addresses the full range of carrier applications, including residential and business voice services, wireless voice and multimedia, trunking and tandem switching, carrier interconnection and enhanced services. Sonus' voice infrastructure solutions are deployed in service provider networks worldwide. Founded in 1997, Sonus is headquartered in Westford, Massachusetts. Additional information on Sonus is available at http://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' Quarterly Report on Form 10-Q for the period ended March 31, 2008, filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements. Risk factors include among others: the impact of material weaknesses in our disclosure controls and procedures and our internal control over financial reporting on our ability to report our financial results timely and accurately; the unpredictability of our quarterly financial results; risks and uncertainties associated with the Company's restatement of its historical stock option granting practices and accounting including regulatory actions or litigation; risks associated with our international expansion and growth; consolidation in the telecommunications industry; and potential costs resulting from pending securities and patent litigation against the Company. 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.

About Tata Communications

Tata Communications Limited along with its global subsidiaries (Tata Communications) is a leading global provider of the new world of communications. The company leverages its Tata Global Network, vertical intelligence and leadership in emerging markets, to deliver value-driven, globally managed solutions to the Fortune 1000 and mid-sized enterprises, service providers and consumers.

The Tata Communications portfolio includes transmission, IP, converged voice, mobility, managed network connectivity, hosted data center, communications solutions and business transformation services to global enterprises & service providers, as well as broadband and content services to Indian consumers. The Tata Global Network encompasses one of the most advanced and largest submarine cable networks, a Tier-1 IP network, connectivity to more than 200 countries across 300 PoPs and more than one million square feet of data center space. Tata Communications serves its customers from its offices in 80 cities in 40 countries worldwide. Tata Communications has a strategic investment in South African operator Neotel, providing the company with a strong anchor to build an African footprint.

The number one global international wholesale voice operator and number one provider of International Long Distance, Enterprise Data and Internet Services in India, the company was named "Best Wholesale Carrier" at the World Communications Awards in 2006 and was named the "Best Pan-Asian Wholesale Provider" at the 2007 Capacity Magazine Global Wholesale Telecommunications Awards for the second consecutive year.

Becoming the leading integrated provider to drive and deliver a new world of communications, Tata Communications became the unified global brand for VSNL, VSNL International, Teleglobe, Tata Indicom Enterprise Business Unit and CIPRIS on February 13, 2008.

Tata Communications Ltd. is a part of the $29 billion Tata Group; it is listed on the Bombay Stock Exchange and the National Stock Exchange of India and its ADRs are listed on the New York Stock Exchange (NYSE: TCL).

www.tatacommunications.com

Forward-looking and cautionary statements

Certain words and statements in this release concerning Tata Communications and its prospects, and other statements including those relating to Tata Communications' expected financial position, business strategy, the future development of Tata Communications' operations and the general economy in India or elsewhere, are forward-looking statements. Such statements involve known and unknown risks, uncertainties and other factors, including financial, regulatory and environmental, as well as those relating to industry growth and trend projections, which may cause actual results, performance or achievements of Tata Communications, or industry results, to differ materially from those expressed or implied by such forward-looking statements. The important factors that could cause actual results, performance or achievements to differ materially from such forward-looking statements include, among others, failure to increase the volume of traffic on Tata Communications' network, failure to develop new products and services that meet customer demands and generate acceptable margins, failure to successfully complete commercial testing of new technology and information systems to support new products and services, including voice transmission services, failure to stabilize or reduce the rate of price compression on certain of the company's communications services, failure to integrate strategic acquisitions and changes in government policies or regulations of India or elsewhere and, in particular, changes relating to the administration of Tata Communications' industry, and, in general, the economic, business and credit conditions in India and elsewhere. Additional factors that could cause actual results, performance or achievements to differ materially from such forward-looking statements, many of which are not in Tata Communications' control, include, but are not limited to, those risk factors discussed in Tata Communications' various filings with the United States Securities and Exchange Commission. These filings are available at www.sec.gov. Readers are cautioned not to place undue reliance on these forward-looking statements, which reflect management's views only as of the date of this release. Tata Communications is under no obligation to, and expressly disclaims any obligation to, update or alter its forward-looking statements.

Tata Communications and the Tata Communications logo are registered service or trade marks of Tata Communications Ltd and/or its subsidiaries.