Cisco Cisco Unified Contact Center Enterprise 9.0(2) Prospecto
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Cisco Unified Contact Center Enterprise 7.5 SRND
Chapter 3 Design Considerations for High Availability
Unified CM and CTI Manager Design Considerations
The servers in a Unified CM cluster communicate with each other using the Signal Distribution Layer
(SDL) service. SDL signaling is used only by the CallManager service to talk to the other CallManager
services to make sure everything is in sync within the Unified CM cluster. The CTI Managers in the
cluster are completely independent and do not establish a direct connection with each other. CTI
Managers route only the external CTI application requests to the appropriate devices serviced by the
local CallManager service on this subscriber. If the device is not resident on its local Unified CM
subscriber, then the CallManager service forwards the application request to the appropriate Unified CM
in the cluster.
(SDL) service. SDL signaling is used only by the CallManager service to talk to the other CallManager
services to make sure everything is in sync within the Unified CM cluster. The CTI Managers in the
cluster are completely independent and do not establish a direct connection with each other. CTI
Managers route only the external CTI application requests to the appropriate devices serviced by the
local CallManager service on this subscriber. If the device is not resident on its local Unified CM
subscriber, then the CallManager service forwards the application request to the appropriate Unified CM
in the cluster.
shows the flow of a device request to another Unified CM in the cluster.
Figure 3-5
CTI Manager Device Request to a Remote Unified CM
Although it might be tempting to register all of the Unified CCE devices to a single subscriber in the
cluster and point the Peripheral Gateway (PG) to that server, this configuration would put a high load on
that subscriber. If the PG were to fail in this case, the duplex PG would connect to a different subscriber,
and all the CTI Manager messaging would have to be routed across the cluster to the original subscriber.
It is important to distribute devices and CTI applications appropriately across all the call processing
nodes in the Unified CM cluster to balance the CTI traffic and possible failover conditions.
cluster and point the Peripheral Gateway (PG) to that server, this configuration would put a high load on
that subscriber. If the PG were to fail in this case, the duplex PG would connect to a different subscriber,
and all the CTI Manager messaging would have to be routed across the cluster to the original subscriber.
It is important to distribute devices and CTI applications appropriately across all the call processing
nodes in the Unified CM cluster to balance the CTI traffic and possible failover conditions.
The external CTI applications use a CTI-enabled user account in Unified CM. They log into the CTI
Manager service to establish a connection and assume control of the Unified CM devices associated to
this specific CTI-enabled user account, typically referred to as the JTAPI user or PG user. In addition,
given that the CTI Managers are independent from each other, any CTI application can connect to any
CTI Manager in the cluster to perform its requests. However, because the CTI Managers are
independent, one CTI Manager cannot pass the CTI application to another CTI Manager upon failure. If
the first CTI Manager fails, the external CTI application must implement the failover mechanism to
connect to another CTI Manager in the cluster.
Manager service to establish a connection and assume control of the Unified CM devices associated to
this specific CTI-enabled user account, typically referred to as the JTAPI user or PG user. In addition,
given that the CTI Managers are independent from each other, any CTI application can connect to any
CTI Manager in the cluster to perform its requests. However, because the CTI Managers are
independent, one CTI Manager cannot pass the CTI application to another CTI Manager upon failure. If
the first CTI Manager fails, the external CTI application must implement the failover mechanism to
connect to another CTI Manager in the cluster.
For example, the Agent PG handles failover for the CTI Manager by using its duplex servers, sides A
and B, each of which is pointed to a different subscriber in the cluster, and by using the CTI Manager on
those subscribers. It is important to note these connections from the PG are managed in hot standby
mode, which means only one side of the PG is active at any given time and connected to the CTI Manager
on the subscriber. The PG processes are designed to prevent both sides from trying to be active at the
same time to reduce the impact of the CTI application on Unified CM. Additionally, both of the duplex
PG servers (Side A and Side B) use the same CTI-enabled JTAPI or PG user to log into the CTI Manager
applications. However, only one Unified CM PG side allows the JTAPI user to register and monitor the
and B, each of which is pointed to a different subscriber in the cluster, and by using the CTI Manager on
those subscribers. It is important to note these connections from the PG are managed in hot standby
mode, which means only one side of the PG is active at any given time and connected to the CTI Manager
on the subscriber. The PG processes are designed to prevent both sides from trying to be active at the
same time to reduce the impact of the CTI application on Unified CM. Additionally, both of the duplex
PG servers (Side A and Side B) use the same CTI-enabled JTAPI or PG user to log into the CTI Manager
applications. However, only one Unified CM PG side allows the JTAPI user to register and monitor the
ICM
PG
76604
Unified CM Publisher
(CTI Manager and
CallManager Services)
Unified CM Subscriber
(CTI Manager and
CallManager Services)
Unified CM Subscriber
(CTI Manager and
CallManager Services)
Request: IPCC
agent ext. 101
Device not on local
Unified CM
IP phone ext. 101
Device
found
Forward request
IP phone ext. 100
IP
IP