[JOINT FILING AGREEMENT CISCO SYSTEMS INTERNATIONAL B.V. Coks Stoffer Director CISCO SYSTEMS NETHERLANDS HOLDINGS B.V. Coks Stoffer Director CISCO SYSTEMS INTERNATIONAL SARL Petra Lindner Director Jean-Marc Servat Director CISCO SYSTEMS (BERMUDA) LTD Petra Lindner] [CUSIP No. 90138A103 13G Page 2 of 15 Pages 1 NAMES OF REPORTING PERSONS/I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Cisco Systems International B.V. CSIBV]

[JOINT FILING AGREEMENT Dated: February 2, 2012 Matrix Partners China I, L.P. David Su Director Matrix Partners China I-A, L.P. David Su Director Matrix China Management I, L.P. David Su Director Matrix China I GP GP, Ltd. David Su] [SCHEDULE 13G (Rule 13d–102) (Amendment No. _________) * 21Vianet Group, Inc. (Name of Issuer) Class A Ordinary Shares, par value US$0.00001 per share (Title of Class of Securities) 90138A 10 3 (CUSIP Number) December 31, 2011 (Date of Event Which Requires Filing of this Statement) o Rule 13d-1(b) o Rule 13d-1(c) x Rule 13d-1(d) *The remainder of this cover page]