[OpenSIPS-Users] detecting mediaproxy across multiple opensips instances

[Iñaki Baz Castillo]

2009/6/9 Dan Pascu <dan at ag-projects.com>:
>> Is there a way the second Opensips proxy can detect the fact the
>> first one
>> has already engaged the mediaproxy?
>
> You could add a SIP header and not start mediaproxy if present. Or use
> some heuristics on the IP addresses from the SDP (origin IP vs c= line
> IP). Or depending on your topology, you can know that a certain proxy
> has a special relationship with the caller/callee and it's the only
> one that should call engage_media_proxy()

nathelper module (RtpProxy) adds a SDP line when force_rtpproxy()
success and modifies the message:
  a=nortpproxy:yes

In case other proxy also tries to use RtpProxy for a request already
forzed by other proxy, then "force_rtpproxy()" will return "false"
since it detects the line "a=nortpproxy:yes" in the SDP so the second
Rtpproxy is not used and $rc is false.

However, this is required in RtpProxy since it doesn't allow a
RtpProxy talking with other (dead lock would occur). This doesn't
happen in MediaProxy.


-- 
Iñaki Baz Castillo
<ibc at aliax.net>