AW: [Sip-implementors] Active Passive SDP extensions!

[Christian Stredicke]

What we do is sending additional information that indicates both the private address and the public address. This is done both in the SDP part *and* the contact, as there we have the same problem.   For two-tier NAT, there would be three addresses.   I already proposed this to the MIDCOM group months ago, but no feedback so far. I think it’s the only way to do it.     INVITE sip:[EMAIL PROTECTED] SIP/2.0 Via: SIP/2.0/UDP 217.230.188.194:22188;branch=z9hG4bK-zak6pmm81wpf Max-Forwards: 70 From: "Christian Stredicke" <sip:[EMAIL PROTECTED]>;tag=3hdf7b6ynj To: <sip:[EMAIL PROTECTED]> Call-ID: [EMAIL PROTECTED] CSeq: 1 INVITE Contact: <sip:[EMAIL PROTECTED]:22188;srcadr=192.168.0.4%3A5060;transport=udp;line=1> User-Agent: snom200-1.14d Accept-Language: en Accept: application/sdp Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, NOTIFY, SUBSCRIBE, PRACK, MESSAGE Supported: timer, 100rel, replaces Session-Expires: 7200 Content-Type: application/sdp Content-Length: 322 v=0 o=root 12723 12723 IN IP4 217.230.188.194 s=SIP Call c=IN IP4 217.230.188.194 t=0 0 m=audio 22339 RTP/AVP 0 101 a=rtpmap:0 pcmu/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 a=x-private:192.168.0.4:10004 217.230.188.194:22339     -- Dr.-Ing. Christian Stredicke sip:[EMAIL PROTECTED]   -----Urspr�ngliche Nachricht----- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Im Auftrag von Rahul Gulati Gesendet: Montag, 2. Dezember 2002 07:14 An: [EMAIL PROTECTED] Cc: Jonathan Rosenberg Betreff: [Sip-implementors] Active Passive SDP extensions!   Hi, All,   I had a question regarding extensions to SDP to make it NAT friendly, some *drafts* mention using "active" to indicate UAs ( behind NAT ) which want to initiate a bi-directional RTP/TCP connection and using "passive" for UAs at the receiving end.   Is there a procedure in the SIP-SDP *standards* by which we can specify an active side of a TCP connection or an active side of a bi-directional RTP connection?   Best Regards' Rahul