June 27, 2019 Daryl E. Raiford Chief Financial Officer Ribbon Communications Inc. 4 Technology Drive Westford, MA 01886 Re: Ribbon Communications Inc. Form 10-K for Fiscal Year Ended December 31, 2018 Filed March 4, 2019 Dear Mr. Raiford: We have completed our review of your filing. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Sincerely, Division of Corporation Finance Office of Information Technologies and Services