Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

CME Redundancy

Is it scenario possible:

SiteA 7960-->CME--T1--CME-->SITEB 7960

Can I set this up so that ip phones in site A registers with CME in siteA. If CME in siteA fails, the phones will register with CME in siteB across the T1 WAN link. The reverse from siteB to siteA, will also be true.

CME in siteB will act as backup for CME in siteA and vice versa.

Both CME have T1 PRI connection to the PSTN.

will this work?

Hall of Fame Super Silver

Re: CME Redundancy

It would not work dynamically. You would need to change the DHCP scope (or manual configuration) to point to the second TFTP IP address.


New Member

Re: CME Redundancy

If you need CME redundancy, check out the verified designs. The 3825 and 3845 solutions are configured with redundancy.

Running CME on both routers requires duplicating the configuration, I suggest running SRST on the second router.

You need to purchase an additional router for each site.

Re: CME Redundancy

Actually, I've played with this a bit. If you add the second CME to the DHCP Option 150 array (and it must be configured as an array), the phone will try a second TFTP server (CCM or CME).

The phone will bounce back and forth until it gets an active tftp server/registration.

New Member

Re: CME Redundancy

This was my thought before I asked the question. I was thinking if I configure the CME ip address of both CME routers for DHCP option 150, then the phones will try registering with the second DHCP option, if the first fails. It will look something like this:

ip dhcp pool CME


option 150 ip


Re: CME Redundancy

That's correct.

No magic here. The phone will place in Network Option #8 (TFTP Server 1) and in Network Option #42 (TFTP Server 2).

Glad to help.

Please don't forget to rate the posts...


CreatePlease to create content