[Asterisk-Dev] RFC2833, Asterisk, and Cisco

[Alistair Cunningham]

All,

We've discovered a potential incompatibility between Asterisk and Cisco
routers. We're using G.792 and RFC2833.

Cisco --> SIP --> Cisco works.

Cisco --> SIP --> Asterisk --> SIP --> Cisco does not. Voice works, but
when the calling Cisco sends DTMF, it is not heard by an IVR on the
called Cisco router. A libpcap trace taken on the Asterisk machine is at:

http://integrics.com/downloads/asterisk_cisco.trc

It looks fine to me. Asterisk sets the RTP event length to 800; I tried
setting it to 424, which is a value I previously saw the calling Cisco
send. This had no effect.

Asterisk is CVS HEAD from around a week ago. We've also tried 1.0.7 with
no difference. We've tried various 12T IOS loads, all with the same result.

-- 
Alistair Cunningham,
Integrics Ltd,
+44 (0)7870 699 479
http://integrics.com/