audio drops midway through call or loud beeping sound

[kdotten36]

I've got two issues I could use some help on regarding voice quality and audio dropping altogether on external calls.

Running CUCM 8.0 and calling out through two 2921 routers version 15.0(1r)M9.  3 Verizon PRIs split between interfaces on the routers.

1.  User calls to PSTN, call is connected, after 5 or 10 minutes, the other party can suddenly no longer hear our user.  Hanging up and calling back resolves it.

2.  PSTN calls our User, they chat...suddenly there is a long beeping sound and the parties must hang up and reconnect the call.

I'm at a loss for what to do next.  I've got some clocking errors on one of the 3 interfaces being used, but I've gotten reports of these issues occuring on all 3 t1 cards on either 2921 router at some point, so it doesn't seem to be isolated to a bad card or hardware.

Any help is appreciated, anyone ever experienced these issues?

[kosterbrink]

Regarding the first issue:

We have had a similar issue that a call dropped on a h.323 gateway after 5 mins, and a firewall dropped h.323 packets after 5 mins.

If there is a fw in between, check h.323 timers and temp turn off h.323 inception.

regards,

Kai

[kdotten36]

It's an mgcp gateway and there's no firewall between our voice routers and the PSTN, thanks for the reply though.