hi, generally, the UA doesn't put its private port unless there is a NAT ALG which translates them...
it generally asks before for public address and ports. Some technics exist which are called turn, stun, ice... etc.... moreover there is some technics to treat the case of signalisation stream ! it s too a problem for them because it s difficult for them to pass through nats ! u can find below the bibliography i use to understand how work nats. 1. TEREDO Overview. Microsoft TechNet, Janvier 2003. 2. Srisuresh, P., Holdrege, M., IP Network Address Translator (NAT) Terminology and Considerations. IETF RFC 2663, Août 1999. 3. Hain, T., Architectural Implications of NAT. IETF RFC 2993, November 2000. 4. Elkik, A., Garanto, H., Porquet, J., VAD/DTX : Techniques de base et intérêts pratiques. 5. Rosenberg, J., Weinberger, J., Huitema, C., Mahy, R., STUN - Simple Traversal of User Datagram Protocol (UDP) Through Network Address Translators (NATs). IETF RFC 3489, March 2003. 6. Mächler, P., SIP Architecture with NAT Version 1.0. Mai 2004. 7. Audet, F., Nortel, Ed., Jennings, C., NAT Behavioral Requirements for Unicast UDP. IETF Draft draft-ietf-behave-nat-udp-00.txt (Work in Progress), Janvier 2005. 8. Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., Schooler, E., SIP : Session Initiation Protocol. IETF RFC 3261, Juin 2002. 9. Paulsamy, V., Chatterjee, S., Network Convergence and the NAT/Firewall Problems. IEEE, 2002. 10. Boulton, C., Rosenberg, J., Best Current Practices for NAT Traversal for SIP. IETF Draft draft-ietf-sipping-nat-scenarios-02 (Work in Progress), Octobre 2004. 11. Rosenberg, J., Schulzrinne, H., An Extension to the Session Initiation Protocol (SIP) for Symmetric Response Routing. IETF RFC 3581, August 2003. 12. Jennings, C., Hawrylyshen, A., SIP Conventions for UAs with Outbound Only Connections. IETF Draft draft-jennings-sipping-outbound-01 (Work in Progress), Février 2005. 13. Mahy, R., Connection Reuse in the Session Initiation Protocol (SIP). IETF Draft draft-ietf-sip-connect-reuse-03.txt (Work in Progress), Octobre 2004. 14. Bhatia, M., Ramachandran, S., Kulshreshtha, G., Devdhar, R., SIP Session Border Control Requirements. IETF Draft draft-bhatia-sipping-sbc-00 (Work in Progress), Janvier 2005. 15. Camarillo, G., Hautakorpi, J., Penfield, R., Hawrylyshen, A., Functionality of Existing Session Border Controller (SBC). IETF Draft draft-camarillo-sipping-sbc-funcs-00 (Work in Progress), Février 2005. 17. Rosenberg, J., Mahy, R., Huitema, C., Traversal Using Relay NAT (TURN). IETF Draft draft-rosenberg-midcom-turn-07 (Work in Progress), Février 2005. 18. Rosenberg, J., Interactive Connectivity Establishment (ICE) : A Methodology for Network Address Translator (NAT) Traversal for Multimedia Session Establishment Protocols. IETF Draft draft-ietf-mmusic-ice-04 (Work in Progress), Février 2005. 19. A Technical Guide to UPnP. 2003, Allied Telesyn International, Corp. 20. Kolic, R., The Advantages of the UPnP* Internet Gateway Device. Intel Developer UPDATE Magazine, Janvier 2002. 21. Poulidis, P., Internet Gateway Device (IGD), UPnP Forum. 22. Srisuresh, P., Kuthan, J., Rosenberg, J., Molitor, A., Rayhan, A., Middlebox Communications architecture and framework. IETF RFC 3303, Août 2002. 23. Swale, R.P., Mart, P. A., Sijben, P., Brim, S., Shore, M., Middlebox Communications (midcom) Protocol Requirements. IETF RFC 3304, Août 2000. 24. Stiemerling, M., Quittek, J., Taylor, T., Middlebox Communications (MIDCOM) Protocol Semantics. IETF RFC 3989, Février 2005. 25. Yon, D., Connection-Oriented Media Transport. IETF Draft Draft-ietf-mmusic-sdp-comedia-05.txt (Work in Progress), Septembre 2003. 26. Yon, D., Camarillo, G., TCP-Based Media Transport in the Session Description Protocol. IETF Draft draft-ietf-mmusic-sdp-comedia-10 (Work in Progress), Novembre 2004. 27. Wing, D., Symmetric RTP and RTCP Considered Helpful. IETF Draft draft-wing-mmusic-symmetric-rtprtcp-01 (Work in Progress), Octobre 2004. 28. Huitema, C., Real Time Control Protocol (RTCP) attribute in Session Description Protocol (SDP). IETF RFC 3605, Octobre 2003. 29. Rosenberg, J., Best Current Practices for NAT Traversal for SIP. IETF Draft draft-ietf-sipping-nat-scenarios-01 (Work in Progress), Octobre 2004. 30. Rosenberg, J., NAT traversal Considerations. IETF Draft draft-iab-nat-traversal-considerations-00 (Work in Progress), Août 2004. Arnault [EMAIL PROTECTED] a écrit : 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 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. --------------------------------- 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
