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CCM Fail Over & Call Persistance Through Gateways...

I am testing various Cisco PRI gateways in a CCM cluster (2x MCS7835 running v3.09) to understand call persistance during CallManager fail over - i.e. for a 24*7 voice environment. I have the following results when failing the "active" CCM subscriber (so that IP Phones & gateways are supported by the publisher):

6624 - IP Phone to/from analogue Calls remain up with speech path

VG200 (MGCP) - IP Phone to/from analogue calls remain up with speech path

IOS H.323 - calls are dropped (as expected as the gateway re-homes onto the other CallManager!)

DE-30+ - IP Phone ingress/egress calls lose speech path

6608-E1- IP Phone ingress/egress calls lose speech path

Now drop and re-establish all the calls, when the failed CCM (subscriber) is restored and the IP Phones and gateways re-register there is no interruption in the speech paths!!!! (Execpt for the IOS H.323 mode gateways which will drop the calls, again)

My real question is, have I missed some fundamental config or are there resticted gateways that support call persistance during CCM failovers? I had understood that Skinny based gateways maintained calls during CCM failovers - my testing shows this not to be the case!

Lastly, I had heard that there was a coming CCM v3.1 or IOS feature for H.323 gateways that will preservce calls during failovers - does anyone know if this is the case?

Regards... Phil.C

Cisco Employee

Re: CCM Fail Over & Call Persistance Through Gateways...

Phil, your findings seem correct to me for CallManager 3.0(x) releases of software.

In CallManager 3.1, all the Skinny gateways such as the 6608-E1, 6624, and DE-30+ will actually use the MGCP protocol to signal to CallManager. The speech path will survive if the CallManager they are registered to fails.

Also note that certain IOS platforms, like VG200, 2600, 3600, as well as a couple others, will have newer IOS MGCP software that will also be able to speak MGCP with CallManager 3.1, even with other interface types in addition to FXO/FXS, such as PRI and CAS. So they will be able to have the speech preserved on a CallManager failure as well.