大家好，
这是我用Wirelshark抓到的SIP邀请包和应答包：
No. Time Source Destination Protocol Info
5 2011-11-25 11:31:46.009850 xxx.xxx.xxx.xxx 192.168.1.105 SIP/SDP Request: INVITE sip:90070048@xxx.xxx.xxx.xxx:25922;transport=UDP, with session description
Session Initiation Protocol
Request-Line: INVITE sip:90070048@xxx.xxx.xxx.xxx:25922;transport=UDP SIP/2.0
Message Header
From: "7dmofedhjpev2h1ta9hdrj6gg8t"<sip:7dmofedhjpev2h1ta9hdxxx.xxx.xxx.xxx@192.168.8.20>;tag=5608328-1408a8c0-13c4-2831b8-628cd8c9-2831b8
To: <sip:90070048@xxx.xxx.xxx.xxx:25922;transport=UDP>
Call-ID: 56aedd8-1408a8c0-13c4-2831b8-1fdfb3b1-2831b8@192.168.8.20
CSeq: 1 INVITE
Via: SIP/2.0/UDP 192.168.8.20:5060;rport;branch=z9hG4bK-2831b8-9d023880-355ecae7
Allow: INVITE,ACK,OPTIONS,REGISTER,INFO,REFER,SUBSCRIBE,NOTIFY,BYE
User-Agent: DonJin SIP Server 2.2.0
Max-Forwards: 70
Contact: <sip:7dmofedhjpev2h1ta9hdxxx.xxx.xxx.xxx@xxx.xxx.xxx.xxx>
Content-Type: application/SDP
Content-Length: 300
Message Body
Session Description Protocol
Session Description Protocol Version (v): 0
Owner/Creator, Session Id (o): DJXMS 0 0 IN IP4 192.168.8.20
Session Name (s): DJXMS
Connection Information (c): IN IP4 xxx.xxx.xxx.xxx
Bandwidth Information (b): CT:1000
Time Description, active time (t): 0 0
Media Description, name and address (m): audio 10216 RTP/AVP 18 0 8 4 96 98 99
Media Attribute (a): rtpmap:18 G729/8000
Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute (a): rtpmap:8 PCMA/8000