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WESTFORD, Mass., January 22, 2003 – Sonus Networks, Inc. (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today reported its financial results for its fourth quarter and fiscal year ended December 31, 2002, in accordance with U.S. generally accepted accounting principles (GAAP).

Revenues for the fourth quarter of fiscal 2002 were $12.7 million compared with $38.9 million in the same period last year. Net loss for the fourth quarter of fiscal 2002 was $12.8 million or $0.07 per share compared with a net loss for the fourth quarter of fiscal 2001 of $13.4 million or $0.07 per share.

Revenues for fiscal year 2002 were $62.6 million compared with $173.2 million for fiscal year 2001.

Net loss for fiscal year 2002 was $68.5 million or $0.36 per share compared with a net loss for fiscal year 2001 of $645.4 million or $3.74 per share.

"We made considerable progress in building our business fundamentals in Q4," said Hassan Ahmed, president and CEO, Sonus Networks. "We reported a sequential increase in revenues and a reduced net loss compared to the third quarter, and our cash balance increased as well. The gains made in the quarter are reflective of progress with our customers and our continued focus on Sonus' financial metrics."

During the quarter, Sonus announced that NTT Communications, one of the world's leading carriers, is using Sonus' packet voice infrastructure solutions to offload modem-generated Internet traffic from its circuit-switched network, and has also begun a field trial of enterprise VoIP services using the Sonus platform. Earlier this week, Sonus announced that NuVox, an integrated communications provider serving the Midwestern and Southeastern United States, selected Sonus to develop a VoIP network that will carry all of NuVox's long distance voice traffic, as well as offload Internet traffic from NuVox's circuit-switched local voice network.

One of Sonus' existing customers, Global Crossing, achieved a significant milestone during the quarter, highlighting the scalability and robustness of Sonus' voice infrastructure solutions. Global Crossing carried more than one billion minutes of voice traffic for carrier and enterprise customers on its Sonus-based VoIP network in the month of November alone.

Further expanding its presence in international markets, Sonus announced relationships with two new distribution partners in the quarter. Welltech Computer Corporation will provide the full range of Sonus packet voice products to the Taiwanese carrier market, and COMPTA will distribute and support the complete Sonus product line in Portugal.

In November, Sonus was again named the leading provider of carrier-class packet voice equipment, a position the company has held for nine consecutive quarters. Market analysis firms In-Stat/MDR, Infonetics Research and Synergy Research Group issued third quarter 2002 market share reports identifying Sonus as the industry leader in several key service provider packet telephony market segments.

"Looking ahead, our 2003 priorities are clear," continued Ahmed. "We are focused on building our customer base, expanding into new target markets, and continuing to deliver the product innovations that have set us apart in the market. Additionally, we will continue to manage our business with precision, driving toward profitability."

About Sonus Networks

Sonus Networks, Inc., is a leading provider of packet voice infrastructure products for the new public network. With its Open Services ArchitectureTM (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking, residential access and Centrex, tandem switching, and IP voice termination, as well as enhanced services. Sonus' award-winning voice infrastructure solutions, including media gateways, softswitches and network management systems, are deployed in service provider networks worldwide. Sonus, founded in 1997, is headquartered in Westford, Massachusetts. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain projections or other forward-looking statements regarding future events or the future financial performance of Sonus 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 Sonus' Quarterly Report on Form 10-Q, dated November 13, 2002 and filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements. These risk factors include, among others, the adverse effect of recent developments in the telecommunications industry, the weakened financial position of many service providers, Sonus' ability to grow its customer base, dependence on new product offerings, market acceptance of its products, rapid technological and market change and manufacturing and sourcing risks. The Company undertakes no duty to update any forward-looking statement to conform the statement to actual results or changes in the Company's expectations.

Sonus is a registered trademark of Sonus Networks. Open Services Architecture is a trademark of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.

(A) These Adjusted Condensed Consolidated Statements of Operations are for informational purposes only and are not in accordance with US generally accepted accounting principles (GAAP).  These statements exclude the impact of the amortization of stock-based compensation, amortization of goodwill and purchased intangible assets, the write-off of goodwill and purchased intangible assets and restructuring charges (benefits).

(A) These Adjusted Condensed Consolidated Statements of Operations are for informational purposes only and are not in accordance with US generally accepted accounting principles (GAAP).  These statements exclude the impact of the write-off of inventory and purchase commitments, amortization of stock-based compensation, amortization of goodwill and purchased intangible assets, the write-off of goodwill and purchased intangible assets, restructuring charges (benefit) and in-process research and development expenses.