Hi!
I've read about the above topic in the arcives and now I've got the same problem.
User A is behind a symmetric NAT -> a new port is bound for every different (external ip, external port) pair. User B has a connection to the net without any NAT or firewall.
User A wants to have a SIP+RTP session with user B. How?
I guess basically what is needed is forming of a SIP message like "send the your reply to the same ip and same port from where you have received this" and user A can send this to user B.
For the RTP session, a pretty similar thing would be needed like, A says to B: "I send you the RTP stream on your x port, send your rtp stream back to the same ip and port from where you receive mine".
How to setup such a SIP packet? Or maybe there is a standard solution for this already? (STUN wont help in this case I guess, and TURN is not an option for me.)
I've read about "symmetric SIP + symmetric RTP" maybe that is the same as I've described above?
Thanks Istvan
Use SER nathelper module and rtpproxy. Use SIP ping from SER every few seconds (not too sparse, because NAT will close; but not too frequent either - use 8 seconds). If your device is capable of it - use SIP ping and RTP/RTCP ping every 8 seconds.
-- Regards, Arek Bekiersz
Istvan De wrote:
Hi!
I've read about the above topic in the arcives and now I've got the same problem.
User A is behind a symmetric NAT -> a new port is bound for every different (external ip, external port) pair. User B has a connection to the net without any NAT or firewall.
User A wants to have a SIP+RTP session with user B. How?
I guess basically what is needed is forming of a SIP message like "send the your reply to the same ip and same port from where you have received this" and user A can send this to user B.
For the RTP session, a pretty similar thing would be needed like, A says to B: "I send you the RTP stream on your x port, send your rtp stream back to the same ip and port from where you receive mine".
How to setup such a SIP packet? Or maybe there is a standard solution for this already? (STUN wont help in this case I guess, and TURN is not an option for me.)
I've read about "symmetric SIP + symmetric RTP" maybe that is the same as I've described above?
You are right. The UA of user B needs to support symmetric RTP. Their is also an extension for SDP called co-media which allows you to explicitly tell the other side "I will start the media stream" or "you should start the media stream". But I think it is not a standard yet, and not too much vendors implemented the draft yet.
Nils
On Tuesday 31 January 2006 03:16, Istvan De wrote:
Hi!
I've read about the above topic in the arcives and now I've got the same problem.
User A is behind a symmetric NAT -> a new port is bound for every different (external ip, external port) pair. User B has a connection to the net without any NAT or firewall.
User A wants to have a SIP+RTP session with user B. How?
I guess basically what is needed is forming of a SIP message like "send the your reply to the same ip and same port from where you have received this" and user A can send this to user B.
For the RTP session, a pretty similar thing would be needed like, A says to B: "I send you the RTP stream on your x port, send your rtp stream back to the same ip and port from where you receive mine".
How to setup such a SIP packet? Or maybe there is a standard solution for this already? (STUN wont help in this case I guess, and TURN is not an option for me.)
I've read about "symmetric SIP + symmetric RTP" maybe that is the same as I've described above?
Thanks Istvan
Serusers mailing list serusers@lists.iptel.org http://lists.iptel.org/mailman/listinfo/serusers
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Arek Bekiersz -
Istvan De -
Nils Ohlmeier