Wireshark · Wireshark-dev: Re: [Wireshark-dev] T.38 codec problem!!!

[Jaap Keuter <jaap.keuter@xxxxxxxxx>]

Hi,

Go to preferences for RTP and change "Treat RTP version 0 packets" into T.38 
packets.

That might help,
Jaap

Deka Sanjeeb Kumar-KHBJ46 wrote:
> Hi All,
>
> I was trying to send FAX over IP network.
>
> I enabled G729 and t.38 codec on both endpoints.
>
> While checking the Wireshark trace of the session, i saw that first 
> negotiation was done with G729 and media started flowing using this codec.
>
> After some time re-negotiation happened with t.38 codec and FAX was 
> properly transmitted.
>
> But in the Wireshark trace could not see RTP packets with t.38 codec. 
> RTP using G729 was still flowing even after the successfull negotiation 
> with t.38. However the SSRC of the new G729 stream was changed to 
> 0x0000(earlier it was a different value).
>
> Moreover, i could see "Unknown RTP version 0" in the Wireshark trace 
> after the second negotiation(negotiation with t.38).
>
> I am not sure whether FAX was transmitted using G729 or t.38.
>
> Could anyone help me out for the above scenario?
>
> Regards.
>
> Sanjeeb