Extension Mobility service redundancy

[Scott Bailey]

Is extention mobility a service that has to be pointed to the Pub and are there any best practices or solutions that have been used to maintain the service in the event of the Pub is down?  While there is only one service URL I'm curious if there is any way to add resiliency by using a load balancer or DNS SRV records.

While extension mobility is the main reason for the question, this also applies to the URL settings for directories and other services that at least in our environment point directly to the Pub's IP address.

[luchtcm · Accepted solution]

The best place I know to point you to is the SRND guide which has a section on "High Availability for IP Phone Services": http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/8x/cmapps.html#wp1185533

You're essentially right on with your ideas on load balancing and DNS.

We've created a new fully qualified domain name services URL for each IP phone service that essentially points to a single IP. In the event of an outage, we'll simply swap IP addresses. Yeah, the change isn't instanteous, but given that none of our IP phone services are critical, we're willing to live with the limitations of our setup.

[Scott Bailey]

Luchtcm, thanks for the quick response and the link to the SRND guide.  This helps a lot.

[henkvandam]

Ther is another solution to get this working.

some of my customers have been using a sso application from a company called rsconnect. they have created an em-sso.

the application 'knows' which cucm is online and uses that server to send the login/logout requests to.

you can even setup a list of cucm servers and change the order of the prefered ones. so there is no need for SLB or manually updating IP's anymore