TATA COMMUNICATIONS AND SONUS NETWORKS UNVEIL STRATEGIC PLAN FOR GLOBAL IP-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.