Cisco Cisco Unified Contact Center Enterprise 9.0(2) Design Guide

Cisco Unified Presence 7.0 servers may be deployed as a single cluster split across a WAN link. This 
type of deployment is known as clustering over the WAN. However, the WAN latency requirements are 
very strict and difficult to achieve on WAN connections, making such deployments unlikely. As a result, 
Unified Expert Advisor has not been tested, and currently is not supported, with this configuration.

For more information on clustering over the WAN, refer to the Cisco Unified Communications SRND 
Based on Cisco Unified Communications Manager, available at 

Cisco Unified Presence contains not only a presence server, but also a SIP proxy server, and both are 
required for Unified Expert Advisor deployments. The proxy server has two purposes in a Unified Expert 
Advisor deployment: first, as a way to define the entire SIP dial plan in one place, and second, as an 
integral element in the Unified Expert Advisor failover strategy.

Although the Cisco Unified Presence 6.x server does not offer failover support, the proxy server does. 
In addition, Unified Expert Advisor can currently be configured to point to only one such proxy server; 
failover among SIP proxy servers is not supported.

If Unified CVP is part of the deployment, you might prefer for Unified CVP to use the Cisco Unified 
Presence publisher as one of its SIP proxy servers, so that you have to configure the dial plan only once. 
However, this benefit should be weighed against the performance impact that is incurred by making one 
Cisco Unified Presence server responsible for IM and presence services, SIP proxy services, and (in 
Microsoft Office Communicator deployments) federation overhead to Microsoft Office Communications 
Server (OCS), on top of its existing publisher responsibilities.

Runtime servers may be either simplexed or duplexed. In a simplexed configuration, both simplexed and 
duplexed Unified ICM PGs are supported, but duplexed Runtime servers require duplexed 
Unified ICM PGs as well.

The following considerations apply to these types of configurations:

Any component that is simplexed becomes a single point of failure in the deployment.

If the expert advisor PIM is co-resident with another PIM (such as a Cisco Unified Communications 
Manager PIM) that is duplexed, then the Expert Advisor PIM must also be duplexed even if the 
Runtime Server itself is simplexed. However, there is no machine count penalty for following this 
requirement because no new machines are being introduced to carry the expert advisor PIMs in this 
scenario.

In order to reduce server count for small deployments, it is possible for PIMs to share Unified ICM PGs 
and for multiple PGs to be hosted on the same physical machine, as long as all Unified ICM sizing 
guidelines, co-residency rules, and physical proximity rules are observed. Most Unified Expert Advisor