[OpenSIPS-Users] OpenSIPS-mediaproxy, Asterisk (packet2packet bridge) - problem with RTP

[Ruud Klaver]

Hi Dimitrios,
On 02 Jul 2009, at 13:17, Dimitrios Giannakopoulos wrote:

> Hi,
>
> So, according to our scenario the asterisk has private ip. Any traffic
> from/to the asterisk can be routed to/from our network.
> The Network trace (between asterisk and opensips) shows that
> mediaproxy does not forward rtp packets to asterisk.
> I tried the rtpproxy component instead of mediaproxy  and the scenario
> (B) worked.
>
>
> On Thu, Jul 2, 2009 at 11:26 AM, Ruud Klaver<ruud at ag-projects.com>  
> wrote:
>> Hi,
>>
>> On 02 Jul 2009, at 08:58, Dimitrios Giannakopoulos wrote:
>>
>>> Hi all,
>>> Thanks for the help.
>>>
>>> I have set nat=no  but problem persists.
>>
>> So is your Asterisk on a public IP? Could you at least confirm with a
>> network trace that mediaproxy is forwarding RTP packets from the  
>> gatways
>> (from both sessions) to Asterisk, but that it is not sending RTP  
>> back?
>>
>> Ruud Klaver
>> AG Projects
>>

If your asterisk puts a private IP for itself in the SDP, mediaproxy  
can never know where to forward the RTP it receives from the gateway  
to, so it waits for RTP to come in from Asterisk so it can learn its  
IP. Apparently Asterisk is also waiting for RTP to come in from the  
relay, so basically you have a standoff situation. You're making  
Asterisk function as a relay as well, and if you put two relays in a  
path they will have this standoff situation unless one of them starts  
forwarding the packets already to the IP that was in the SDP.  
Obviously Asterisk does not do this and mediaproxy can't do it because  
the IP in the SDP is private.

Ruud Klaver
AG Projects