[Freeswitch-users] RTP port rewriting stops working when combined with transcoding?

[Michael Jerris]

we can only auto-change port when we actually get packets to know where to send.  Are you actually getting that traffic in the silk case?  Possible you are getting silence suppression causing no packets to be sent?

On Jul 17, 2014, at 5:22 AM, Kees Jan Koster <kjkoster at gmail.com> wrote:

> Dear All,
> 
> I am trying to figure out why I see what I see.
> 
> When I make a call using the same codec (say, PCMA/8000 on both sides), FreeSwitch rewrites the RTP stream's IP address and port for me. That I like, since my FreeSwitch is behind NAT.
> 
>> From the logs:
> 
> 2014-07-16 12:32:36.815907 [INFO] switch_rtp.c:3738 Auto Changing port from 1.2.3.4:4040 to 5.6.7.8:4040
> 2014-07-16 12:32:36.995906 [INFO] switch_rtp.c:3738 Auto Changing port from 9.10.11.12:12345 to 13.14.15.16:41730
> 
> Now, when I try to use two different codecs, this behaviour stops. Say I use SILK/8000 on one leg and PCMA/8000 on the other.
> 
>> From the logs and without changing the configuration or restarting FreeSwitch:
> 
> 2014-07-16 12:35:36.495902 [INFO] switch_rtp.c:3738 Auto Changing port from 1.2.3.4:4042 to 5.6.7.8:4042
> 
> The other line is missing and ngrep reveals how FreeSwitch stubbornly sends RTP audio to the wrong port and IP address.
> 
> Further testing shows:
> 
> PCMA  -> PCMA: IP/port is rewritten
> SILK  -> PCMA: IP/port is *not* rewritten
> GSM   -> PCMA: IP/port is rewritten
> Speex -> PCMA: IP/port is *not* rewritten
> 
> How can I have transcoding *and* RTP IP/port rewriting work at the same time, please?
> 
> Is this a per-codec thing?
> 
> --
> Kees Jan
> 
> http://java-monitor.com/
> kjkoster at kjkoster.org
> +31651838192
> 
> Change is good. Granted, it is good in retrospect, but change is good.
>