WESTFORD, Mass., December 22, 2003 – Sonus Networks (Nasdaq: SONS), a leading provider of carrier packet voice infrastructure solutions, today announced that it will relocate its corporate headquarters to Chelmsford, Massachusetts. Sonus has signed a sublease under which it will occupy more than 130,000 square feet of space at 250 Apollo Drive in Chelmsford. The company is expected to complete the move of its operations to the new facility by the end of the first quarter 2004.

“We had several goals in mind when selecting the location of our new corporate headquarters,” said Hassan Ahmed, president and CEO, Sonus Networks. “It was very important that we stay in the Route 495 area, the heart of Massachusetts’ telecommunications corridor, for our employees and for our customers. Additionally, we required state-of-the art engineering, professional services and customer support facilities. We are extremely pleased to have found a new home that meets our criteria, and at the same time offers financial advantages over our current facilities. We are looking forward to making the move to Chelmsford.”

Sonus Networks Inc.