Universal Mobile Telecommunications System (UMTS); LTE; Evolved Packet System (EPS); 3GPP Sv interface (MME to MSC@ and SGSN to MSC) for SRVCC (V10.5.0; 3GPP TS 29.280 version 10.5.0 Release 10)
"The present document describes the Sv interface between the Mobility Management Entity (MME) or Serving GPRS Support Node (SGSN) and 3GPP MSC server enhanced for SRVCC. Sv interface is used to support Inter-RAT handover from VoIP/IMS over EPS to CS domain over 3GPP UTRAN/GERAN access or from UTRAN (HSPA) to 3GPP UTRAN/GERAN access. If there is no specific indication@ the term ""MSC server"" denotes 3GPP MSC server enhanced for SRVCC as defined in 3GPP TS 23.216 [2]."