呼叫保持流程

标签：作者qq 鸣人370905569

呼叫保持流程图

呼叫保持信令：

1）  用户1000发送re-INVITE消息给IPBX，需要保持1000和1002之间的通话。Re-INVITE消息携带SDP中c=IN IP4 0.0.0.0，说明该re-INVITE消息是呼叫保持消息。

INVITE sip:1002@192.168.50.22:5060SIP/2.0

Via: SIP/2.0/UDP192.168.50.20:9588;branch=z9hG4bK-d8754z-da66ec3fc2251561-1---d8754z-;rport

Max-Forwards: 70

Contact:<sip:1000@192.168.50.20:9588>

To: <sip:1002@192.168.50.22>;tag=54267485a

From:"1000"<sip:1000@192.168.50.22>;tag=8c7df95e

Call-ID:ZjBiM2MxNDQ3ZWNlM2JhYjAwYWEyNGJlMWE4NjZjYmQ.

CSeq: 3 INVITE

Allow: INVITE, ACK, CANCEL, OPTIONS,BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO

Content-Type: application/sdp

Supported: replaces

User-Agent: Bria Professional release2.4 stamp 49381

Content-Length: 238

v=0

o=hua 9 3 IN IP4 192.168.50.20

s=CounterPath Bria Professional

c=IN IP4 0.0.0.0

t=0 0

m=audio 7624 RTP/AVP 0 101

a=fmtp:101 0-15

a=rtpmap:101 telephone-event/8000

a=sendonly

a=x-rtp-session-id:84405823042846CFA4F793EB20FEB7E6

2） IPBX收到re-INVITE请求响应，保持用户1000和1002之间的通话，并且给用户1002播放背景音乐，给用户1000回复确认消息200 OK.

SIP/2.0 200 OK

Via: SIP/2.0/UDP192.168.50.20:9588;branch=z9hG4bK-d8754z-da66ec3fc2251561-1---d8754z-;rport

From:"1000"<sip:1000@192.168.50.22>;tag=8c7df95e

To:<sip:1002@192.168.50.22>;tag=54267485a

Call-ID:ZjBiM2MxNDQ3ZWNlM2JhYjAwYWEyNGJlMWE4NjZjYmQ.

CSeq: 3 INVITE

User-Agent: FreeSwitch

Contact:<sip:1002@192.168.50.22:5060>

Content-Type: application/sdp

Content-Length: 201

v=0

o=session 1639146064 1639146065 IN IP4192.168.50.22

s=play

c=IN IP4 192.168.50.22

t=0 0

m=audio 10476 RTP/AVP 0 101

a=rtpmap:0 PCMU/8000

a=rtpmap:101 telephone-event/8000

a=fmtp:101 0-16

3） 用户1000收到IPBX发送确认请求消息200 OK，发送ACK消息给IPBX

ACK sip:1002@192.168.50.22:5060 SIP/2.0

Via: SIP/2.0/UDP192.168.50.20:9588;branch=z9hG4bK-d8754z-ef0e4b7cfe6a7548-1---d8754z-;rport

Max-Forwards: 70

Contact:<sip:1000@192.168.50.20:9588>

To:<sip:1002@192.168.50.22>;tag=54267485a

From:"1000"<sip:1000@192.168.50.22>;tag=8c7df95e

Call-ID:ZjBiM2MxNDQ3ZWNlM2JhYjAwYWEyNGJlMWE4NjZjYmQ.

CSeq: 3 ACK

User-Agent: Bria Professional release2.4 stamp 49381

Content-Length: 0

呼叫保持流程

标签：作者qq 鸣人370905569

原文地址：http://blog.csdn.net/wh8_2011/article/details/46659805