Hi Arnault, I am jotting down a scenario here. Tell me if it is wrong.
1. Invite is send with SDP with private parameters for rtp and rtcp. 2. NAT probe can't be connected because RTP and RTCP port of external party is not known. 3. external party sends 200OK with its rtp and rtcp port(optional). 4. NAT probe is contacted to get external mapping of RTP and RTCP port. 5. ACK is sent with updated mapped RTP and RTCP port in SDP. Cheers, Vivek -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Arnault Nagle Sent: Monday, July 04, 2005 7:00 PM To: [email protected] Subject: RE: [Sip-implementors] NAT traversal in SIP and of course, u must ask before the nat to give u another port (and even IP address if u need !!) Arnault Nagle <[EMAIL PROTECTED]> a écrit :hello, this answer is in Huitema, C., Real Time Control Protocol (RTCP) attribute in Session Description Protocol (SDP). IETF RFC 3605, Octobre 2003 you can specify the port ofor the RTCP packets. c=IN IP4 1.2.3.4 m=audio 14567 RTP/AVP 0 a=rtcp:23456 ++ Arnault [EMAIL PROTECTED] a écrit : Hi All, I have a query related with NAT traversal in SIP. In case of restricted cone and port restricted cone, SIP ua1 connect to NAT probe to get it external address. Consider the case when UA1 knows that its internal RTP ip:port which is 10.0.0.1:8000 and NAT probe gives external ip:port 205.205.205.205:1234. Now SIP UA will send c=205.205.205.205 and m = AUDIO 1234 in SDP. With this information other end UA2 will be able to send RTP packet on 1234 of NAT which will lend successfully on 8000 of SIP UA1. But SIP UA1 will open 8001 for RTCP and UA2 will assume 1235 is RTCP port for UA1. In this case how 2 way media path is established? I know external query works for restricted cone and port restricted cone NAT then am i missing something? Cheers, Vivek Confidentiality Notice The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain confidential or privileged information. If you are not the intended recipient, please notify the sender at Wipro or [EMAIL PROTECTED] immediately and destroy all copies of this message and any attachments. _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors --------------------------------- Appel audio GRATUIT partout dans le monde avec le nouveau Yahoo! Messenger Téléchargez le ici ! --------------------------------- Appel audio GRATUIT partout dans le monde avec le nouveau Yahoo! Messenger Téléchargez le ici ! _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors Confidentiality Notice The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain confidential or privileged information. If you are not the intended recipient, please notify the sender at Wipro or [EMAIL PROTECTED] immediately and destroy all copies of this message and any attachments. _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
