[c-nsp] ISDN PRI to SIP in 2811, RTP fails one way AFTER first DTMF is sent?

[Andy Koch]

On Thu, Jul 1, 2010 at 09:54, Roger Wiklund <copse at xy.org> wrote:
> Hi
>
> I have a very strange issue.
>
> Using a Cisco 2811 router with PRI connecting to customers PBX. SIP trunk
> towards Verizon.
> Incoming and outgoing calls are working just fine, using G.729 codec.
> DTMF RFC288 configured, and I can see in the SIP invites and 200ok messages
> that it is indeed using RFC2833.
>
> However, when customer makes an outgoing call, and the press any key, I can
> hear the tone, and I see the DTMF in the router with debug voip rtp session
> but after that, RTP is dead in the outbound direction.

Is the RTP stream still present but just no audio being encoded, or
does the RTP stream stop?


> Any tips?
>
> I've tried G711, IOS upgrade, all dtmf-relay methods available, no go =( I'm
> starting to thing its something with the PBX..

Does a T-Bird exhibit the same symptoms?  Can you hear audio if you
monitor the PRI B channel when this happens?

Andy
gawul00 at gmail.com