[Users] nat_helper: multiple media IP address in SDP

[Nicolas Olivier]

Hi Bogdan,

Ok, I understand now. But I still encounter the problem because:
- rtpproxy only rewrites the c= from media part (but it should be fine as you said) despite what a quick look in the rtpproxy code comments say ("We 
have to change ports in m-lines, and also change IP addresses in c-lines which can be placed either in session header (fallback for all medias) or 
media description.")
- the centrex (which is an asterisk by the way) take only into account the c= from the session part, not the one from media part



regards,
Nicolas

Bogdan-Andrei Iancu wrote:
> Hi Nicolas,
> 
> it;s perfectly ok - see the SDP RFC : an SDP may contain a default c= in
> the session part; each media section (m=) may contain an ip (c=); if it
> doesn't the session c= will be used.
> 
> regards,
> bogdan
> 
> Nicolas Olivier wrote:
> 
>  >
>  > Hi,
>  >
>  > I've got a gateway which is only used for rounting and rtp proxying
>  > between providers and centrexes.
>  >
>  > On reply to an INVITE, one of our provider send back a "183 Session
>  > Progress". The problem is that in the SDP block, we've got 2 media IP
>  > address and rtpproxy only rewrite one.
>  >
>  > Finally, the provider establish rtp session with our gateway, and our
>  > centrex directly with the provider.
>  >
>  >   provider                  gateway                  centrex
>  > 172.16.0.10               192.168.1.10              192.168.1.20
>  >      RTP     ------------->   RTP      ------------>   RTP
>  >       ^-------------------------------------------------|
>  >
>  > So my questions are, is it possible to have multiple IP address in SDP
>  > and if so, how can I tell rtpproxy to rewrite all of them.
>  >
>  > Coming from provider:
>  >
>  > SIP/2.0 183 Session Progress.
>  > Via: SIP/2.0/UDP
>  > 192.168.1.10;branch=z9hG4bKdd67.a4cc2c44.0,SIP/2.0/UDP
>  > 192.168.1.20:5062;branch=z9hG4bKdd67.08f45a33.0,SIP/2.0/UDP
>  > 192.168.1.20:5060;branch=z9hG4bK4af242b7.
>  > From: "02" <sip:0143132445 at 192.168.1.20>;tag=as226ce7b9.
>  > To: <sip:0123456789 at 192.168.1.20:5062>;tag=3123AAA8-20C5.
>  > Date: Tue, 11 Apr 2006 09:10:29 GMT.
>  > Call-ID: 079ab6663e403ff44a1107e5111b075f at 192.168.1.20.
>  > Server: Cisco-SIPGateway/IOS-12.x.
>  > CSeq: 102 INVITE.
>  > Allow-Events: telephone-event.
>  > Contact: <sip:677238#0123456789 at 172.16.0.10:5060>.
>  > Record-Route:
>  > 
> <sip:192.168.1.10;ftag=as226ce7b9;lr=on>,<sip:192.168.1.20:5062;ftag=as226ce7b9;lr=on>. 
> 
>  >
>  > Content-Disposition: session;handling=required.
>  > Content-Type: application/sdp.
>  > Content-Length: 261.
>  > .
>  > v=0.
>  > o=CiscoSystemsSIP-GW-UserAgent 3448 4768 IN IP4 172.16.0.10.
>  > s=SIP Call.
>  > c=IN IP4 172.16.0.10.
>  > t=0 0.
>  > m=audio 18322 RTP/AVP 18 101.
>  > c=IN IP4 172.16.0.10.
>  > a=rtpmap:18 G729/8000.
>  > a=fmtp:18 annexb=no.
>  > a=rtpmap:101 telephone-event/8000.
>  > a=fmtp:101 0-16.
>  >
>  > Forwarded to centrex:
>  >
>  > SIP/2.0 183 Session Progress.
>  > Via: SIP/2.0/UDP
>  > 192.168.1.20:5062;branch=z9hG4bK43a4.3e96aba3.0,SIP/2.0/UDP
>  > 192.168.1.20:5060;branch=z9hG4bK3213db83.
>  > From: "02" <sip:0143132445 at 192.168.1.20>;tag=as1a2f900d.
>  > To: <sip:0123456789 at 192.168.1.20:5062>;tag=3121D1B4-1BFD.
>  > Date: Tue, 11 Apr 2006 09:08:28 GMT.
>  > Call-ID: 08467c5e299ab833106517c63d3edc2e at 192.168.1.20.
>  > Server: Cisco-SIPGateway/IOS-12.x.
>  > CSeq: 102 INVITE.
>  > Allow-Events: telephone-event.
>  > Contact: <sip:677238#0123456789 at 172.16.0.10:5060>.
>  > Record-Route:
>  > 
> <sip:192.168.1.10;ftag=as1a2f900d;lr=on>,<sip:192.168.1.20:5062;ftag=as1a2f900d;lr=on>. 
> 
>  >
>  > Content-Disposition: session;handling=required.
>  > Content-Type: application/sdp.
>  > Content-Length: 277.
>  > .
>  > v=0.
>  > o=CiscoSystemsSIP-GW-UserAgent 565 174 IN IP4 172.16.0.10.
>  > s=SIP Call.
>  > c=IN IP4 172.16.0.10.
>  > t=0 0.
>  > m=audio 36296 RTP/AVP 18 101.
>  > c=IN IP4 192.168.1.10.
>  > a=rtpmap:18 G729/8000.
>  > a=fmtp:18 annexb=no.
>  > a=rtpmap:101 telephone-event/8000.
>  > a=fmtp:101 0-16.
>  > a=nortpproxy:yes.
>  >
>  >
>  > openser.cfg
>  >
>  > (...)
>  >
>  >  onreply_route[1] {
>  >          if (status =~ "(180)|(183)|2[0-9][0-9]") {
>  >                  fix_nated_contact();
>  >                  if (!search("^Content-Length:[ ]*0")) {
>  >                          force_rtp_proxy();
>  >                  };
>  >          } else if (nat_uac_test("1")) {
>  >                  fix_nated_contact();
>  >          };
>  >  }
>  >
>  > (...)
>  >
>  > Best regards,
>  > Nicolas Olivier
>  >
>  >
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