CME Failover configuration

Unanswered Question
Nicholas Matthews Tue, 12/16/2008 - 07:24

This is an interesting scenario.

It's hard to say for sure without doing some testing.

The first obstacle is making sure the configuration stays the same on both routers. Shouldn't be too bad, but there isn't a way to automate this easily.

You won't be able to gracefully fail this over, either. The other IP address will not be aware of the phone states, and this will cause the CME to receive messages from phones that it is not expecting. The CME will have problems with that.

The part I'm unsure about is if the CME receives messages from phones that in a different state than it expects, if it will make the phone re-register. If not, I don't think the phones will actually re-register.

If CME does detect this bad state, it may tell the phones to reset/re-register, but if not I don't think this would be a working system.

Some other possible solutions:

-Use different addresses, manually set the TFTP servers on the phones

-Use different addresses, and use something like 'ip source-address x secondary y' , 'ip source-address y secondary x' in telephony service. (CME 4.2 and later I believe).

-Manually change the TFTP files the phones download to include the address of the other CME

-Put in a feature request with your sales team to have redundant IP address support for CME

This may work, but I don't think it has ever been tested. Thus, it probably wouldn't be supported in the HSRP environment you're thinking of.


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