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RIBBON COMMUNICATIONS INC. 6500 CHASE OAKS BLVD. SUITE 100 PLANO, TX 75023D48302-P53789You invested in RIBBON COMMUNICATIONS INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the stockholder meeting to be held on May 27, 2021.Get informed before you vote View the Notice, Proxy Statement and 2020 Annual Report online OR you can receive a free paper or email copy of the materials by requesting prior to May 13, 2021. If you would like to request a copy of the materials for this and/or future shareholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy.Smartphone users Point your camera here and vote without entering a control numberVirtually at:Vote Virtually at the Meeting* May 27, 2021 10:00 A.M. EDTwww.virtualshareholdermeeting.com/RBBN2021*Please check the meeting materials for any special requirements for meeting attendance.V1 




 Vote at www.ProxyVote.comTHIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters.Voting ItemsBoard Recommends1. Election of Directors Nominees: 1a. Mariano S. de BeerFor 1b. R. Stewart Ewing, Jr. For 1c. Bruns H. Grayson For 1d. Beatriz V. Infante For 1e. Bruce W. McClelland For 1f. Krish A. Prabhu For 1g. Shaul Shani For 1h. Richard W. Smith For 1i. Tanya Tamone For 2. To ratify the appointment of Deloitte & Touche LLP as Ribbon Communications’ independent registered public accounting firm for the fiscal year ending December 31, 2021. For 3. To approve, on a non-binding, advisory basis, the compensation of Ribbon Communications’ named executive officers as disclosed in the “Compensation Discussion and Analysis” section and the accompanying compensation tables and related narratives contained in the Proxy Statement. For NOTE: In their discretion, the proxy holders are authorized to vote upon other business, if any, that may properly come before the meeting and any adjournments, continuations, or postponements thereof.Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Sign up for E-delivery”.D48303-P53789