X0303 4 2011-03-01 0001105472 SONUS NETWORKS INC SONS 0001490373 Vishwanathan Kumar C/O SONUS NETWORKS, INC. 4 TECHNOLOGY PARK DRIVE WESTFORD MA 01886 0 1 0 0 VP, Eng. & Chief Architect Common Stock 2011-03-01 4 M 0 56250 1.74 A 137440 D Common Stock 2011-03-01 4 S 0 90565 3.79 D 46875 D Employee Stock Option (right to buy) 1.74 2011-03-01 4 M 0 56250 0 D 2019-08-17 Common Stock 56250 93750 D The option exercise and sale reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 5, 2010. 25% of the shares underlying this option vested on August 3, 2010. The remaining 75% of the shares underlying this option will then vest in equal monthly increments for the following 36 months through August 3, 2013. Kumar Vishwanathan 2011-03-02