【文章內容簡介】 ect,Proxy,3.4 重定向呼叫,User A,User B,Redirect,Proxy,3.4 重定向呼叫,ACK sip:UserB@there.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bKbf9f44 MaxForwards: 70 From: BigGuy 。tag=9fxced76sl To: LittleGuy 。tag=53fHlqlQ2 CallID: 12345600@here.com CSeq: 1 ACK ContentLength: 0,User A,User B,Redirect,Proxy,3.4 重定向呼叫,INVITE sip:UserB@everywhere.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bK74bf9 MaxForwards: 70 From: BigGuy 。tag=9fxced76sl To: LittleGuy CallID: 12345600@here.com CSeq: 2 INVITE Contact: ContentLength: 0,User A,User B,Redirect,Proxy,3.4 重定向呼叫,SIP/2.0 100 Trying Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bK74bf9 。received=100.101.102.103 From: BigGuy 。tag=9fxced76sl To: LittleGuy CallID: 12345600@here.com CSeq: 2 INVITE ContentLength: 0,User A,User B,Redirect,Proxy,3.4 重定向呼叫,INVITE sip:UserB@111.112.113.114 SIP/2.0 Via: SIP/2.0/UDP ss2.wcom.com:5060。branch=z9hG4bK721e418c4.1 Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bK74bf9 。received=100.101.102.103 MaxForwards: 69 RecordRoute: From: BigGuy 。tag=9fxced76sl To: LittleGuy CallID: 12345600@here.com CSeq: 2 INVITE Contact: ContentLength: 0,User A,User B,Redirect,Proxy,3.4 重定向呼叫,SIP/2.0 180 Ringing Via: SIP/2.0/UDP ss2.wcom.com:5060。branch=z9hG4bK721e418c4.1 。received=2.3.4.5 Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bK74bf9 。received=100.101.102.103 RecordRoute: From: BigGuy 。tag=9fxced76sl To: LittleGuy 。tag=314159 CallID: 12345600@here.com CSeq: 2 INVITE Contact: ContentLength: 0,User A,User B,Redirect,Proxy,3.4 重定向呼叫,SIP/2.0 180 Ringing Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bK74bf9 。received=100.101.102.103 RecordRoute: From: BigGuy 。tag=9fxced76sl To: LittleGuy 。tag=314159 CallID: 12345600@here.com CSeq: 2 INVITE Contact: ContentLength: 0,User A,User B,Redirect,Proxy,3.4 重定向呼叫,SIP/2.0 200 OK Via: SIP/2.0/UDP ss2.wcom.com:5060。branch=z9hG4bK721e418c4.1 。received=2.3.4.5 Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bK74bf9 。received=100.101.102.103 RecordRoute: From: BigGuy 。tag=9fxced76sl To: LittleGuy 。tag=314159 CallID: 12345600@here.com CSeq: 2 INVITE Contact: ContentType: application/sdp ContentLength: 152 v=0 o=UserB 2890844527 2890844527 IN IP4 everywhere.com s=Session SDP c=IN IP4 111.112.113.114 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000,User A,User B,Redirect,Proxy,3.4 重定向呼叫,SIP/2.0 200 OK Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bK74bf9 。received=100.101.102.103 RecordRoute: From: BigGuy 。tag=9fxced76sl To: LittleGuy 。tag=314159 CallID: 12345600@here.com CSeq: 2 INVITE Contact: ContentType: application/sdp ContentLength: 152 v=0 o=UserB 2890844527 2890844527 IN IP4 everywhere.com s=Session SDP c=IN IP4 111.112.113.114 t=0 0 m=audio 3456 RTP/AVP 0 a=rtpmap:0 PCMU/8000,User A,User B,Redirect,Proxy,3.4 重定向呼叫,ACK sip:UserB@everyhere.com SIP/2.0 Via: SIP/2.0/UDP here.com:5060。branch=z9hG4bK74bf9 MaxForwards: