TORTEL COMMUNICATIONS SELECTS SONUS NETWORKS TO REPLACE LEGACY IP-NETWORK

WESTFORD, Mass., May 29, 2008 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in IP
communications infrastructure, today announced that Tortel
Communications Inc., a leading provider of pure IP-telephony solutions
with a strong presence in the United States, Canada, India and Asia,
has selected Sonus to replace its incumbent IP-voice network technology.

Tortel is replacing its
legacy solution to improve the overall quality of service and integrity
of its network. The Company also required a robust, next-generation
solution to enable it to develop and deliver differentiating product
offerings and an improved long distance offering. Due to the simplified
network management and efficient transcoding capabilities of Sonus'
gateway solution, Tortel expects a substantial increase in its network
performance and the ability to devote additional resources to the
development of new services.

"We conducted a thorough
review of competitive solutions before selecting Sonus Networks to
serve as the cornerstone of our enhanced next-generation long distance
voice network," said Dominic Ogbonna, Chief Technology Officer for
Tortel Communications. "Sonus was the only vendor able to provide a
solution that met our requirements for security, scalability,
reliability and management. In addition, by partnering with Sonus, we
saw the opportunity to deliver operational savings and build new
revenue streams through service creation."

Tortel will utilize Sonus'
Network Border Switch (NBS), built on the market-leading GSX9000
platform, which offers carrier class IP-peering and a strong layer of
security. Tortel will take advantage of the peering and advanced
transcoding capabilities that Sonus allows to be built directly into
the gateway, streamlining the switching of traffic between IP-networks
and simplifying network management.

"Tortel is emerging as one of
Canada's leading suppliers of pure IP-telephony and has shown
considerable innovation in developing its networks to enhance customer
experience," said Hassan Ahmed, president, chairman and CEO, Sonus
Networks. "Whether wireline or wireless, we are supporting forward
thinking companies like Tortel in their ambitions to generate new
services for their customers and differentiate their offerings with
market leading IP-services."

About Sonus Networks
Sonus Networks, Inc. is a leading provider of IP-voice infrastructure
solutions 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.