One site only for CUCM, no voice (phones register and act like they work..

[johnk]

Hi All,

We have a CUCM single server in a colo facility with a design similar to this:

Site 1 \

Site 2 - tunnels to colo - CUCM - 2921 CUBE - Sip Trunk

Site 3 /

Last week, in the above example, all was working and then site 3, lost voice capability.  The phones register and act like they make calls (ring the destination end points)(like UDP is being filtered).  Sites 1 and 2 (and more actually) are continuing to work normally (thankfully). 

We've done the old number 7 and rebooted everything, but I haven't seen anything similar to this previously and am asking for good places to look from experienced veterans.

Thanks in advance.

John

[Sreekanth Narayanan · Accepted solution]

Your best bet to troubleshoot this issue is to take packet captures to understand where the RTP packets are being lost. You've mentioned that the calls are getting set up. So this means the signaling is going through. The RTP is being dropped. You need to identify the network topology between the Site 3 phones and the SIP trunk destination.
Site 3 IP phone --- Edge router site 3 ---- Edge router site 1 ---- CUBE ---- SIP Trunk

You can take packet captures at the site 3 phone and the CUBE for starters to understand if the packets that leave the phone reach the CUBE and vice versa.

[johnk]

I found a tunnel that was down due to a recent upgrade we did with the traces. Hadn't gotten around to the traces yet but it was 100% the right answer - all is well!

Thank you!!

[Sreekanth Narayanan]

You're welcome :)