X0306 4 2020-12-08 0001708055 Ribbon Communications Inc. RBBN 0001720721 Marmurek Eric S C/O RIBBON COMMUNICATIONS INC. 4 TECHNOLOGY PARK DRIVE WESTFORD MA 01886 0 1 0 0 SVP, CAO Common Stock 2020-12-08 4 S 0 8304 7.1904 D 33534 D The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $ 7.1866 to $ 7.1937, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price with the ranges set forth in this footnote. Patrick Macken, Attorney-in-Fact 2020-12-10