Datasheet

Cisco Preferred Architecture for
Midmarket Collaboration PAGE 14
Call Control
Recommended Deployment
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Deploy two Cisco Unified CM servers in a cluster configuration that includes a publisher node and a subscriber
node for redundancy.
•
Deploy two IM and Presence Service servers in a cluster configuration that includes a publisher node and a
subscriber node for redundancy.
•
Enable Cisco SRST on the Cisco ISR as a backup service at remote sites to provide high availability.
Note: If full redundancy is not required, a single server may be deployed without loss of functionality.
Benefits
This deployment provides the following benefits:
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Call control is centralized at a single location that serves multiple remote sites.
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Management and administration are centralized.
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Common telephony features are available across voice and video endpoints.
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Single call control and a unified dial plan are provided for voice and video endpoints.
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Critical business applications are highly available and redundant.
Deployment Best Practices
Cisco Unified Communications Manager and IM and Presence Service
Publisher-Subscriber Deployment Model
A Cisco Unified CM cluster or an IM and Presence Service cluster consists of one publisher node and one subscriber
node (Figure 6).
•
The publisher node is the server that is installed first. This server contains the cluster’s configuration database.
Cluster-wide configuration is written to the publisher’s database and replicated on the subscriber.
•
The subscriber node is the server that is installed second. It contains a replica of the publisher’s database. The
subscriber is updated automatically whenever the publisher’s configuration changes.
Clustering provides an automatic redundancy mechanism for endpoints and for Cisco Unified CM services, such as the
ability to receive and process incoming calls. Cisco recommends configuring the Unified CM cluster with the subscriber
node as the primary call-processing server and the publisher node as the backup call-processing server. This
configuration applies to the IM and Presence Service cluster, too. If the IM and Presence Service subscriber node goes
down, then IM and presence capabilities will still be available for Cisco Jabber clients.