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New Member

MGCP No Tone Ringback


I am working on the BritishAirways IPT network, and we are finding a particular MGCP gateway which doesnt provide ringback, when calling out from and IP Phone.

Having looked around on the CCO, I have found this link:

which states:

Use ANN for Ring Back: Uses Cisco Signaling Connection Control Part (SCCP) Annunciator to play a ring back tone (available in Cisco CallManager release 4.0 and later).

We are using CCM Ver4.1.

Will this provide ring back?

Is there an performance impact on the CallManager/cluster as a whole?

Will there be any impact on any other gateways which already do provide ringback?

Thanks in advance

Reza Sadiq

Prime Business Solutions

(Cisco Gold Partner for BA)

Cisco Employee

Re: MGCP No Tone Ringback

Your SCCP ANN is a different thing than what you are troubleshooting.

The problem you are experiencing is probably because your voice path is not cut thru soon enough.. There are some steps you need to take to fix this.. First look at the PRI/CAS messages and when you see a call proceed. Then, check with debug mgcp packet if the gateway is signalling the CCM to do e MDCX. If it is, check the sccp messages and find out if you see the proceed.

Debugs that might help:

debug mgcp pack

ccm traces.

the following web pages might help

New Member

Re: MGCP No Tone Ringback


The second link was useful. It turns out this seems to be a capabilities issue for MGCP gateways and QSig which are being used in this case.

We have requested an PI=8 from the PBX at the other end of the MGCP gateway. The PBX operators are changing their software code to try and provide this. We are told by Cisco TAC that this should provide the correct signalling back to the call manager, so that it can provide ringback tone.

If you have any further ideas, please to recommend.

Thanks in advance


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