7、PRACK消息
1)头字段填写说明
必选头域如下:
Call-id
Cseq
From
To
Max-Forwards
Via
RAck
常用可选头域:
Content-Type
Content-Length
2)消息实例
如下是PRACK消息的参考实例:
PRACK sip:192.168.2.154:5060 SIP/2.0
CSeq: 2 PRACK
Call-ID: 0112114b0ca1d73c3fbdc7036e4672c8@huawei.com
Contact: <sip:01055554444@192.168.2.46>
Content-Length: 0
From: <sip:01055554444@192.168.2.154>;tag=6c789654
To: <sip:01062237400@192.168.2.154>;tag=0012-f1939f63004dbd16
Via: SIP/2.0/UDP 192.168.2.46;branch=z9hG4bK04982ba62
User-Agent: Huawei-MC820/1.0.0
Supported: 100rel
RAck: 1 1 INVITE
1)头字段填写说明
必选头域如下:
Call-id
Cseq
From
To
Max-Forwards
Via
RAck
常用可选头域:
Content-Type
Content-Length
2)消息实例
如下是PRACK消息的参考实例:










