ETSI TS 124 228-2004 数字蜂窝通信系统(第2+阶段).全球移动通信系统(UMTS).基于会话初始协议(SIP)和会话描述协议(SDP)的IP多媒体呼叫控制信令流.第3阶段.3GPP
Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); Signalling flows for the IP multimedia call control based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3 3GPP