Cisco Cisco IPCC Web Option Leaflet

 shows a CTI Manager service failure on Unified CM subscriber C that is used to 

communicate with the Unified CCE PG. The CTI Manager services are running on all the Unified CM 
subscribers in the cluster, but only subscribers C and D are configured to connect to the Unified CCE 
PGs. During this failure, the PG will detect the loss of the JTAPI connection and fail-over to the 
redundant/duplex PG side.

The following conditions apply to this scenario:

All phones and gateways are registered with Unified CM subscriber A.

All phones and gateways are configured to re-home to Unified CM subscriber B (that is, B is the 
backup server). In this case they will not re-home because subscriber A is still functional.

Unified CM subscribers C and D are each running a local instance of CTI Manager and are designed 
to connect to the Unified CCE PGs.

If the Unified CM CTI Manager service on subscriber C fails, the PG side A detects a failure of the 
CTI Manager service and induces a failover to PG side B.

PG side B registers all dialed numbers and phones with the Unified CM CTI Manager service on 
subscriber D, and call processing continues.

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Unified CM D

Unified CM C

Unified CM B

Unified CM A

Fails

ICM synchronzation messages
Unified CM intra-cluster messages
JTAPI messages
H323 or MGCP messages
SCCP messages

Agent PG A

Agent PG B