RTP does not get extablished when the calls is inetiated wiht Gatekeeper

[lal.mohammad]

HI,

We have Three CUCM cluster 7.1.5 and a gatekeeper, the inter-cluster trunk (Gatekeeper control) have been configured.

Site A - outgoing call is fine for site B & C,

Site B - outgoing call is fine for site C & A

Site C - outgoing call is fine for B, outgoing call does not work for A

When the call is made from Site C to site A the phone rings but as soon as the call is received it gives the fast busy tone.

The outgoing call for Site C to Site A works fine if we have the Inter-cluster trunk (non gatekeeper control).

Any suggestion will be appreciated.

Thanks

Lal Mohammad.

[Fernando Rivas Martin]

Hello Mohammad

If the call setup is working but after answering the call is failing, usually means that the media negotiation is the one that failed.

So Gatekeeper already allowed the call, but it is the media negotiation part the one failing.

What codec should the call use between site C and site A?

When using the intercluster trunk (non-gatekeeper controlled)

Are the Device Pool, Media Resource Group List the same as in the non-working case?

Regards
Fernando

[lal.mohammad]

Hi Fernando,

The device pool used is same for the working intercluster trunk (Gatekeeper control) and not working intercluster trunk (Gatekeeper control). the intercluster calls are on G729. and this is the same trunk which is used by the Site B for outgoing call from Site C.

Regards,

Lal Mohammad.

[Steven Holl]

This isn't a GK issue unless your GK has a proxy configured (invia/outvia).  Otherwise, media negotiation happens between the GW endpoints (which in thise case are both CM).  You will want to run a detailed CM trace with h245 enabled to investigate further.  It's likely a codec mistmatch, an issue with the H245 TCP socket opening, or not able to invoke an MTP/transcoder.