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New Member

redundancy and IP Phone Services

Does anyone know how redundancy can be achieved in terms of IP Phone Services. I have a cluster with 2 CCMs. There’s only one services URL, so if that server doesn’t respond, we don’t get any response to pressing the services key on the IP Phone.

The only info on this that I found is in CallManager Features and Services Guide 4.1(3) on page 1-26

“To provide redundancy for the Cisco IP Phone Service, create a

Cisco IP Phone Service that uses the host name rather than the IP address.

The phone functionality for softkeys and filtering, as well as the phone

service, will fail over automatically in the case of a failover.”

But I don’t really understand what they mean by that. Please, help!


Re: redundancy and IP Phone Services

sounds like what they mean is if you have two http servers providing web pages, then you can use a name in the 'Settings URL' field of CCM configuration and if one of the servers fails then the other is available (as long as the name is the same; must be manually; i'll double check)

Re: redundancy and IP Phone Services

Use dns names instead of ip address. which means you will have to setup dns entries in your dns server for your callmanager's ip address

New Member

Re: redundancy and IP Phone Services

But how will it work with DNS? Having multiple records with the same name but different IP addresses?

But what if the web service will be down not the whole server, how will DNS help in this situation?


Re: redundancy and IP Phone Services

Using DNS to resolve the hostname to multiple IP Address, the phones will try the second server if the request to the first server timeout. If the web service is down, then all web request will fail and the phone should try the next server in the list. This is in theroy. Never got a chance to test this.

A better option to ensure redundancy would be to use a Content Switch to monitor the web services in the servers and redirect traffic accordingly.



New Member

Re: redundancy and IP Phone Services

I tested this and even though DNS server returns 2 IP addresses in DNS response, IP phone is not trying to use the second IP address. It keeps trying to set up a TCP session with the server that is down and then times out.