Cisco Unified Contact Center Enterprise Solution Reference ...

Chapter 3 Design Considerations for High Availability
Scenario 2: Agent PG Side A Fails
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Peripheral Gateway Design Considerations
Figure 3-18 shows a failure on PG side A and a failover to PG side B. All CTI Manager and
Cisco Unified CallManager services continue running normally. 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 A and B are each running a local instance of CTI Manager.
When PG side A fails, PG side B becomes active.
PG side B registers all dialed numbers and phones, and call processing continues. Phones and
gateways stay registered and operational with Cisco Unified CallManager subscriber A; they do not
fail-over.
Agents with calls in progress will stay in progress, but with no third-party call control (conference,
transfer, and so forth) available from their agent desktop softphones. After an agent disconnects
from all calls, that agent's desktop functionality is restored to the same state prior to failover.
When PG side A recovers, PG side B remains active and uses the CTI Manager on Cisco Unified
CallManager subscriber B.
Figure 3-18 Scenario 2 – Agent PG Side A Fails
CallManager A
Agent PG A
Fails Agent PG B
M
Scenario 3: Only the Primary Cisco Unified CallManager Subscriber Fails
M
IP
CallManager B
ICM synchronzation messages
CallManager intra-cluster messages
JTAPI messages
H323 or MGCP messages
SCCP messages
Figure 3-19 shows a failure on Cisco Unified CallManager subscriber A. The CTI Manager services are
running on Cisco Unified CallManager subscribers C and D, and the CTI Manager on Cisco Unified
CallManager subscriber C is actively connected to the CallManager Peripheral Gateway (PG) side A.
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