Hi KY,
Sorry man, only two CCM (along with the Primary) can be configured;
Cisco IOS gateways can maintain links to up to **two backup Cisco Unified CallManager servers in addition to a **primary Cisco Unified CallManager. This redundancy enables a voice gateway to switchover to a backup if the gateway loses communication with the primary. The backup server takes control of the devices that are registered with the primary Cisco Unified CallManager. The second backup takes control of the registered devices if both the primary and first backup Cisco Unified CallManager fail. The gateway preserves existing connections during a switchover to a backup Cisco Unified CallManager.
When the primary Cisco Unified CallManager server becomes available again, control reverts to that server. Reverting to the primary server can occur immediately, after a configurable amount of time, or only when all connected sessions are released.
Switchback
Switchback is the process a voice gateway uses to reestablish communication with the primary Cisco Unified CallManager server when the server becomes available again. Switchback can occur immediately, at a specified time after the last active call ends, or after a specified length of time.
MGCP Gateway Fallback
The MGCP gateway maintains a remote connection to a centralized Cisco Unified CallManager cluster by sending MGCP keepalive messages to the Cisco Unified CallManager server at 15-second intervals. If the active Cisco Unified CallManager server fails to acknowledge receipt of the keepalive message within 30 seconds, the gateway attempts to switch over to the next available Cisco Unified CallManager server.
SUMMARY STEPS
1. enable
2. configure terminal
3. ccm-manager redundant-host {ip-address | DNS-name} {ip-address | DNS-name}
4. ccm-manager switchback {graceful | immediate | schedule-time hh:mm | uptime-delay minutes}
5. ccm-manager fallback-mgcp
6. call application alternate
7. exit
8. ccm-manager switchover-to-backup
From this good doc;
http://www.cisco.com/en/US/products/ps6441/products_configuration_guide_chapter09186a00805583bd.html#wp1056830
Hope this helps!
Rob
