Topology Options
This section provides an overview of the system topology and describes the relationship between the types of nodes in the topology.
Clusters
Clusters provide a mechanism for distributing call processing, presence status, and database replication among multiple servers. They provide transparent sharing of resources and features, and enable system scalability.
A cluster comprises a set of Unified Communications Manager nodes and IM and Presence nodes that run compatible software versions.
Publisher Nodes and Subscriber Nodes
Within a cluster, there is a database publisher for each type of node that you install.
When you install Unified Communications Manager, the installation wizard prompts you to specify whether the node you are installing is the first node in the cluster. The first Unified Communications Manager node that you install becomes the publisher node, because it publishes the voice and video database to the other Unified Communications Manager nodes in the cluster. All subsequent nodes in the cluster are called subscriber nodes. Each subscriber node must be associated with the publisher node. You must set up all subscriber nodes in the system topology on the publisher node before you install the software on the subscriber nodes.
When you install IM and Presence nodes, the first node that you install functions as the server for the IM and Presence database. Because this node publishes the database for all of the IM and Presence nodes in the cluster, it is referred to as the IM and Presence database publisher; however, you must install this and all other IM and Presence nodes as subscribers of the Unified Communications Manager publisher node. As with other subscriber nodes, you must add these in the system topology before you install the software.
Topology Options
When installing your cluster, you must decide on the topology that you want to deploy. For example:
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The number of cluster nodes required.
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Whether you will install all cluster nodes in a single location, or if you will install your nodes in separate geographic sites connected via a WAN in order to provide geographic redundancy. For more information on scalability, see Megacluster.
Cluster Topology for IM and Presence
If you are deploying the IM and Presence Service, you must decide before you begin the installation whether you want a Standard Deployment (IM and Presence Service on Unified Communications Manager) or an IM and Presence Centralized Cluster Deployment.
IM and Presence Deployment |
Description |
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Standard Deployment (de-centralized/distributed) ) |
The IM and Presence Service cluster nodes are installed on the physical servers as the Unified Communications Manager telephony cluster. The IM and Presence cluster shares a platform and many of the same services as the telephony cluster. This option requires a 1x1 mapping of Unified CM telephony clusters to IM and Presence clusters. Basic installations order followed is same as mentioned in the Attended Install method. For more information, see the "Installation Methods". For touchless installations, you can install all Unified Communications Manager and IM and Presence Service cluster nodes concurrently in a single process. |
IM and Presence Centralized Cluster Deployment |
The IM and Presence Service central cluster is installed separately from your telephony cluster and may be located on different hardware servers. This deployment removes the 1x1 mapping requirement between telephony clusters and IM and Presence clusters. This allows you to scale your telephony deployment and IM and Presence deployment separately. For basic installations:
For touchless installations, you can install your local Unified Communications Manager publisher node and your IM and Presence Service central cluster in a single process. However, your telephony cluster must be installed separately. For more information, see the "Configure Centralized Deployment" chapter at Configuration and Administration of the IM and Presence Service Guide. |