Cisco Unified Contact Center Enterprise Solution Reference ...

Peripheral Gateway Design Considerations
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Cisco Unified Contact Center Enterprise 7.x SRND
Chapter 3 Design Considerations for High Availability
However, all phones and gateways are registered with Cisco Unified CallManager subscriber A. All
phones and devices will re-home individually to the backup Cisco Unified CallManager subscriber B. If
the device is in use (a phone on a call), it will re-home to backup Cisco Unified CallManager subscriber
B after it is no longer in use.
The following conditions apply to this scenario:
All phones and gateways are registered with Cisco Unified CallManager subscriber A.
All phones and gateways are configured to re-home to Cisco Unified CallManager subscriber B (that
is, B is the backup server).
Cisco Unified CallManager subscribers C and D are each running a local instance of CTI Manager.
If Cisco Unified CallManager subscriber A fails, phones and gateways re-home to the backup
Cisco Unified CallManager subscriber B.
PG side A remains connected and active, with a CTI Manager connection on Cisco Unified
CallManager subscriber C. It does not fail-over because the JTAPI-to-CTI Manager connection has
not failed. However, it will see the phones and devices being unregistered from Cisco Unified
CallManager subscriber A (where they were registered) and will then be notified of these devices
being re-registered on Cisco Unified CallManager subscriber B automatically. During the time that
the agent phones are not registered, the PG will disable the agent desktops to prevent the agents from
attempting to use the system while their phones are not actively registered with a Cisco Unified
CallManager subscriber.
Call processing continues for any devices not registered to Cisco Unified CallManager
subscriber A. Call processing also continues for those devices on subscriber A when they are
re-registered with their backup subscriber.
Agents on active calls will stay in their connected state until they complete the call; however, the
agent desktop will be disabled to prevent any conference, transfer, or other third-party call control
during the failover. After the agent disconnects the active call, that agent's phone will re-register
with the backup subscriber, and the agent will have to log in again manually using the agent desktop.
When Cisco Unified CallManager subscriber A recovers, phones and gateways re-home to it. This
re-homing can be set up on Cisco Unified CallManager to gracefully return groups of phones and
devices over time or to require manual intervention during a maintenance window to minimize the
impact to the call center. During this re-homing process, the CTI Manager service will notify the
Unified CCE Peripheral Gateway of the phones being unregistered from the backup Cisco Unified
CallManager subscriber B and re-registered with the original Cisco Unified CallManager subscriber
A.
Call processing continues normally after the phones and devices have returned to their original
subscriber.
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