Cisco Cisco Customer Response Solution Downloads 设计指南

The following IPCC Express behavior can be expected of IPCC Express if the connection to 
Cisco CallManager primary is lost: 

The JTAPI and Integrated Contact Distribution (ICD) subsystems reconnect to the backup CTIM, as 
it was configured in the IPCC Express JTAPI and ICD subsystem parameters.

All of the application provider resource management gets transferred to the backup server, which in 
this example is the publisher.

CTI devices (CTI ports and route points) re-home to the backup Cisco CallManager server. (Cisco 
recommends that you do not configure any devices on the publisher in a Cisco CallManager cluster with 
multiple servers.) Re-registration takes approximately 500 msecs per single line device or CTI port. 
During this re-registration period, there could be 15 to 20 seconds of call center downtime, and this delay 
can vary with the number of CTI devices in use. Once all devices have been re-registered to the backup 
Cisco CallManager and CTIM, routing of new incoming calls will resume, and IPCC Express agents can 
log in again and accept incoming calls.

If the failed Cisco CallManager is the DCD server authenticating the IPCC Express (the Directory Host 
Name defined in IPCC Express Configuration and Repository, Directory Setup parameters), there is no 
IP application redundancy because the failure of a Cisco CallManager hosting DCD is a single point of 
failure for IP IPCC Express. The following behavior can occur:

LDAP authentication errors will occur in IPCC Express Application Administration.

All incoming calls to the IPCC Express route point will return reorder tone (fast busy).

Agents will not be able to log in again.

For this reason, the subscriber server should be configured as the primary CTIM and Cisco CallManager. 
An option for reducing the downtime is to install a DCD on a standalone Cisco CallManager server in 
the cluster or on an external corporate directory server.

During Cisco CallManager or CTIM failure, expect the following call survivability behavior:

Calls in progress with IPCC Express agents prior to failure are not interrupted.

Calls in queue during failure are dropped.

The average time for failover for a single server with CTI devices ranges from 15 to 20 seconds. 
During this time, incoming calls receive a busy (reorder) tone until all CTI devices have 
re-registered to the backup Cisco CallManager and CTIM.

You can use the following option to provide call continuity during this failure scenario:

Distribute the agents and CTI ports into multiple device pools on Cisco CallManager.

Have route points, CTI ports, and agent devices in a non-failed device pool to continue queuing calls 
and routing them to agents.

If the failed Cisco CallManager and CTIM does not host the IPCC Express application route point, 
agents in a non-failed device pool can continue to accept calls from the queue with no downtime.

Adding a second IPCC Express application with a forward-on-failure to a secondary route point does not 
appear to improve failover time. Testing has shown that the time for Cisco CallManager to detect that 
the application is no longer available (and forward to a second route point) is equal to the time it takes 
for Cisco CallManager to re-register CTI devices to the backup server.