X0303 4 2010-06-15 0001105472 SONUS NETWORKS INC SONS 0001166816 Nottenburg Richard N C/O SONUS NETWORKS, INC. 7 TECHNOLOGY PARK DRIVE WESTFORD MA 01886 1 1 0 0 CEO and President Common Stock 2010-06-15 4 A 0 750000 0 A 1630940 D These are restricted shares that will vest based upon the occurrence of certain events pursuant to the terms of Dr. Nottenburg's retention letter with Sonus Networks, Inc. (the "Company"), which was filed as an exhibit to the Company's Current Report on Form 8-K, filed on May 20, 2010. More specifically, (i) 250,000 restricted shares will vest on the earlier of the date the Board of Directors of the Company (the "Board") relieves him of his duties as President or CEO of the Company other than for Cause (as referenced in the retention letter) or March 31, 2011; (ii) 125,000 restricted shares will vest upon the achievement of the financial metrics in the Company's 2010 operating plan, as previously approved by the Board; (iii) 125,000 restricted shares will vest upon the achievement of the target for bookings from new products, as reflected in the Company's 2010 Incentive Compensation Program Base Plan under the Senior Management Cash Incentive Plan; and (iv) 250,000 retention shares will vest on the earlier of : (A) sixty days after the first day of employment of Dr. Nottenburg's successor, provided that Dr. Nottenburg assists with the transition during such period; (B) the date the Board relieves Dr. Nottenburg of his duties as President or CEO of the Company other than for Cause, if no successor has been appointed by such date; or (C) March 31, 2011. Richard N. Nottenburg 2010-06-17