实践出真知。了解了一些知识，光掌握这些是不够的，还需要动手来操练。那么前面我们也学习了SIP协议的有关内容，这里我们就来分享一个网友的SIP INVITE的操练过程吧。希望对大家能够有用。

SIP INVITE中linphone发出的请求(reguest)

INVITE sip:to@192.168.105.14 SIP/2.0  
Via: SIP/2.0/UDP 192.168.105.5:5060;rport;branch=z9hG4bK2195  
From: ;tag=29244  
To:   
Call-ID: 8103  
CSeq: 20 INVITE  
Contact:   
Content-Type: application/sdp  
Max-Forwards: 70  
User-Agent: Linphone/3.2.1 (eXosip2/3.3.0)  
Subject: Phone call  
Content-Length:   315  
v=0  
o=from 123456 654321 IN IP4 192.168.105.5  
s=A conversation  
c=IN IP4 192.168.105.5  
t=0 0  
m=audio 7078 RTP/AVP 111 110 0 3 8 101  
a=rtpmap:111 speex/16000/1  
a=rtpmap:110 speex/8000/1  
a=rtpmap:0 PCMU/8000/1  
a=rtpmap:3 GSM/8000/1  
a=rtpmap:8 PCMA/8000/1  
a=rtpmap:101 telephone-event/8000  
a=fmtp:101 0-11 

SIP INVITE中linphone发到的回应(response)

SIP/2.0 100 Trying  
Via: SIP/2.0/UDP 192.168.105.5:5060;rport=5060;branch=z9hG4bK2195  
From: ;tag=29244  
To:   
Call-ID: 8103  
CSeq: 20 INVITE  
User-Agent: eXosip/3.3.0  
Content-Length: 0  
-----------------------------------------------------------------------------  
SIP/2.0 101 Dialog Establishement  
Via: SIP/2.0/UDP 192.168.105.5:5060;rport=5060;branch=z9hG4bK2195  
From: ;tag=29244  
To: ;tag=286863750  
Call-ID: 8103  
CSeq: 20 INVITE  
Contact:   
User-Agent: eXosip/3.3.0  
Content-Length: 0  
------------------------------------------------------------------  
SIP/2.0 180 Ringing  
Via: SIP/2.0/UDP 192.168.105.5:5060;rport=5060;branch=z9hG4bK2195  
From: ;tag=29244  
To: ;tag=286863750  
Call-ID: 8103  
CSeq: 20 INVITE  
Contact:   
User-Agent: eXosip/3.3.0  
Content-Length: 0  
------------------------------------------------------------------------  
SIP/2.0 200 OK  
Via: SIP/2.0/UDP 192.168.105.5:5060;rport=5060;branch=z9hG4bK2195  
From: ;tag=29244  
To: ;tag=286863750  
Call-ID: 8103  
CSeq: 20 INVITE  
Contact:   
User-Agent: eXosip/3.3.0  
Content-Length: 0 

SIP INVITE中linphone发出的请求(reguest)

ACK sip:to@192.168.105.14:5060 SIP/2.0  
Via: SIP/2.0/UDP 192.168.105.5:5060;rport;branch=z9hG4bK32434  
From: ;tag=29244  
To: ;tag=286863750  
Call-ID: 8103  
CSeq: 20 ACK  
Contact:   
Max-Forwards: 70  
User-Agent: Linphone/3.2.1 (eXosip2/3.3.0)  
Content-Length: 0  
------------------------------------------------------------------------  
BYE sip:to@192.168.105.14:5060 SIP/2.0  
Via: SIP/2.0/UDP 192.168.105.5:5060;rport;branch=z9hG4bK1384  
From: ;tag=29244  
To: ;tag=286863750  
Call-ID: 8103  
CSeq: 21 BYE  
Contact:   
Max-Forwards: 70  
User-Agent: Linphone/3.2.1 (eXosip2/3.3.0)  
Content-Length: 0 

SIP INVITE中linphone发到的回应(response)

SIP/2.0 200 OK  
Via: SIP/2.0/UDP 192.168.105.5:5060;rport=5060;branch=z9hG4bK1384  
From: ;tag=29244  
To: ;tag=286863750  
Call-ID: 8103  
CSeq: 21 BYE  
User-Agent: eXosip/3.3.0  
Content-Length: 0