Cisco Unified Contact Center Enterprise Solution Reference ...
Cisco Unified Contact Center Enterprise Solution Reference ...
Cisco Unified Contact Center Enterprise Solution Reference ...
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Peripheral Gateway Design Considerations<br />
3-24<br />
<strong>Cisco</strong> <strong>Unified</strong> <strong>Contact</strong> <strong>Center</strong> <strong>Enterprise</strong> 7.x SRND<br />
Chapter 3 Design Considerations for High Availability<br />
CallManager CTI Manager, and it is specific for the version of <strong>Cisco</strong> <strong>Unified</strong> CallManager. This<br />
software module must be downloaded from <strong>Cisco</strong> <strong>Unified</strong> CallManager when the PG is initially set up<br />
to ensure specific version compatibility.<br />
The Agent PG Peripheral Interface Manager (PIM) is also a node-managed process and is monitored for<br />
unexpected failures and automatically restarted. This process manages the higher-level interface<br />
between the <strong>Unified</strong> ICM and the <strong>Cisco</strong> <strong>Unified</strong> CallManager cluster, requesting specific objects to<br />
monitor and handling route requests from the <strong>Cisco</strong> <strong>Unified</strong> CallManager cluster.<br />
In a duplex Agent PG environment, both JTAPI services from both Agent PG sides log into the CTI<br />
Manager upon initialization. <strong>Cisco</strong> <strong>Unified</strong> CallManager PG side A logs into the primary CTI Manager,<br />
while PG side B logs into the secondary CTI Manager. However, only the active side of the <strong>Cisco</strong> <strong>Unified</strong><br />
CallManager PG registers monitors for phones and CTI route points. The duplex Agent PG pair works<br />
in hot-standby mode, with only the active PG side PIM communicating with the <strong>Cisco</strong> <strong>Unified</strong><br />
CallManager cluster. The standby side logs into the secondary CTI Manager only to initialize the<br />
interface and make it available for a failover. The registration and initialization services of the<br />
<strong>Cisco</strong> <strong>Unified</strong> CallManager devices take a significant amount of time, and having the CTI Manager<br />
available significantly decreases the time for failover.<br />
In duplex PG operation, the side that goes active is the PG side that is first able to connect to the <strong>Unified</strong><br />
ICM Call Router Server and request configuration information. It is not deterministic based upon the<br />
side-A or side-B designation of the PG device, but it depends only upon the ability of the PG to connect<br />
to the Call Router, and it ensures that only the PG side that has the best connection to the Call Router<br />
will attempt to go active.<br />
The startup process of the PIM requires that all of the CTI route points be registered first, which is done<br />
at a rate of 5 route points per second. For systems with a lot of CTI route points (for example, 1000),<br />
this process can take as long as 3 minutes to complete before the system will allow any of the agents to<br />
log in. This time can be reduced by distributing the devices over multiple PIM interfaces to the<br />
<strong>Cisco</strong> <strong>Unified</strong> CallManager cluster.<br />
<strong>Cisco</strong> <strong>Unified</strong> CallManager will accept multiple PG/PIM connections on a single cluster, which allows<br />
<strong>Unified</strong> CCE to distribute different types of registrations across multiple connections. For example, one<br />
PIM could be configured to log in as JTAPIuser1 and have only the CTI route points associated with it,<br />
while a second PIM could be logged in as JTAPIuser2 and have the agent IP phones registered to it. This<br />
arrangement would allow agents to log in faster at startup, without having to wait for the dialed numbers<br />
to be registered with CTI Manager first.<br />
<strong>Cisco</strong> <strong>Unified</strong> CallManager Failure Scenarios<br />
A fully redundant <strong>Unified</strong> CCE system contains no single points of failure. However, there are scenarios<br />
where a combination of multiple failures can reduce <strong>Unified</strong> CCE system functionality and availability.<br />
Also, if a component of the <strong>Unified</strong> CCE solution does not itself support redundancy and failover,<br />
existing calls on that component will be dropped. The following failure scenarios have the most impact<br />
on high availability, and <strong>Cisco</strong> <strong>Unified</strong> CallManager Peripheral Interface Managers (PIMs) cannot<br />
activate if either of the following failure scenarios occurs (see Figure 3-16):<br />
Agent PG/PIM side A and the secondary CTI Manager that services the PG/PIM on side B both fail.<br />
Agent PG/PIM side B and the primary CTI Manager that services the PG/PIM on side A both fail.<br />
In either of these cases, the <strong>Unified</strong> ICM will not be able to communicate with the <strong>Cisco</strong> <strong>Unified</strong><br />
CallManager cluster.<br />
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