hi all , i got a promble confuss me for a long time , i have 2 question , could anyone help me out ! my secnario flow map like this : and i got two promble : 1?while pjsip can't explain the ok message sdp , sip message were parse below: SIP/2.0 200 OK Via: SIP/2.0/TCP 192.168.23.138:10124;rport;branch=z9hG4bKPj0068dca41e934c1db20cc10c30035c50;alias Record-Route: <sip:192.168.17.151:5060;transport=tcp;lr> From: "88138" <sip:88138@192.168.17.151>;tag=01ebaf01e0e741acb47604cc30958813 To: <sip:3100 at 172.16.200.24>;tag=as01d21491 Call-ID: 5816233ed41f41e1b967333dabe4b0f7 CSeq: 25405 INVITE Contact: <sip:3100 at 172.16.200.24:5060> Content-Type: application/sdp Allow: INVITE Allow: ACK Allow: CANCEL Allow: OPTIONS Allow: BYE Allow: REFER Allow: SUBSCRIBE Allow: NOTIFY Allow: INFO Allow: PUBLISH Server: Asterisk PBX 1.8.7.0 Supported: replaces Content-Length: 334 v=0 o=root 1332783161 1332783161 IN IP4 172.16.200.24 s=Asterisk PBX 1.8.7.0 c=IN IP4 172.16.200.24 t=0 0 m=audio 17292 RTP/AVP 8 0 3 96 a=rtpmap:8 PCMA/8000 a=rtpmap:0 PCMU/8000 a=rtpmap:3 GSM/8000 a=rtpmap:96 telephone-event/8000 a=fmtp:96 0-16 a=silenceSupp:off - - - - a=ptime:20 a=sendrecv m=video 0 RTP/AVP 97 96 2?why bob received bye the session doesn't finished, but resend reinvte messeage(in-dialog invite) i chcek the sdp parts , the message is trying to modify the sdp , and rebuild media. so if 2 is correct why pjsip will bye before re-invite ? and why the red parts sdp is not one vaild media sdp ? thx a lot. Best regards. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20150615/07f2be78/attachment.html> -------------- next part -------------- A non-text attachment was scrubbed... Name: Catch.jpg Type: image/jpeg Size: 78258 bytes Desc: not available URL: <http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20150615/07f2be78/attachment.jpg>