Cisco Cisco E-Mail Manager Unity Integration Option Design Guide

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Cisco Unified Contact Center Enterprise 7.0, 7.1, and 7.2 SRND
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Chapter 3      Design Considerations for High Availability
Unified CM and CTI Manager Design Considerations
Figure 3-4
Functions of Unified CM and the CTI Manager
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 Unified CM service to talk to the other Unified CM 
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 Unified CM service on this subscriber. If the device is not resident on its local Unified CM 
subscriber, then the Unified CM 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, 
Agent
PG
IVR
143942
JTAPI
SDL
H.323 or SIP
SCCP or SIP 
Unified CM Publisher
(CTI Manager and
CallManager Services)
Unified CM Subscriber
(CTI Manager and
CallManager Services)
Softphone
SDL
JTAPI
Cisco IP Phones
(SCCP or SIP)
V
IP
IP
IP
IP
IP
IP
M
M
M
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