There are two scenarios here that I can think of regarding an IP phone call and verifying the codec in use.

The first is if the call comes in a PRI or FXO interface on the router. If this is the case the commands above will show you that information. Also another useful command is "sho vo call stat" will show you the codecs in use.

Second scenario, is an IP-IP phone call. If you are calling site to site, I dont know of a command that will show the call and the codec in use. To the router, this is just another stream of traffic and will route the traffic accordingly. You could look at the information parameters on the phone itself and see on the display of the phone which codec in use.

Mc

Yes you are right. I wanted to actually show the IP Phone - IP Phone calls, and realise now that the previous info I was looking at was for calls via the PRI/FXO.

I guess yes, the router would only see this as another stream. I seemed to remember seeing this in IOS before - but thinking back, this was when the router was running as a gatekeeper (I think).

In this instance, I can't achieve what I want (which was to verify every WAN call is using specific codec) without verifying CM config / using performance monitor (for concurrent calls / bandwidth remain stats etc.).

Thanks for your help.