[SR-Users] B2BUA removing a=nortpproxy:yes (rtpproxy-1 <---RTP---> rtpproxy-2)

[Klaus Darilion]

Am 24.04.2010 11:25, schrieb Juha Heinanen:
> Iñaki Baz Castillo writes:
>
>   >  If these rtpproxy use the same IP as the Kamailio's SIP signalling IP,
>   >  then there is no problem and no need to use "-r" flag.
>
> inaki,
>
> does it work in the common case where there is two sip proxys and two
> rtpproxies belonging to two organizations that don't have any trust
> relationship between them and ip addresses of the rtpproxies are not the
> same as sip proxy ip addresses?

It depends on the configuration.

IMO a "correct" kamailio/rtpproxy setup uses (note: 'a' implies 'r'):

Alice     Atlanta        Biloxy        Bob
          rtpproxy        rtpproxy
           flags           flags
   <---''---|--'a'--> <--'a'--|------->


This is because Atlante can not know about the setup of Biloxy (if the 
clients are behind, if there are multiple proxies in between). Thus, a 
proxy should perform NAT traversal (rewrite contact untrusted SDP) only 
for the local users. For external users (other domains) the Atlanta 
proxy should not rewrite the contact header and should use received SDP. 
Every domain's proxy is responsible to fix its client's signaling.

regards
klaus