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Oracle® WebLogic Communication Services Administrator's Guide
11g Release 1 (11.1.1)

Part Number E13806-01
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G Deploying a Scalable Presence Deployment

This section describes the recommended and supported deployment topology for a large scale Presence Solution requiring Presence, XDMS, and User Dispatcher. It illustrates the typical flows from a multi-node perspective. Topics include:

G.1 Presence Cluster

A Presence Cluster is defined as a set of Presence Nodes connected after one or more Load Balancers. The Presence Cluster is responsible for processing incoming subscribe and publish requests made towards the presence event-package and for sending out notify's whenever appropriate. The Presence Cluster will also accept and process subscribe requests for the presence.winfo event-package.The Presence Cluster will interact with the XDM Cluster in order to obtain information needed to complete its responsibilities. The information queried of the XDM Cluster is user's presence-rules and pidf-manipulation documents.

The Presence Cluster is layered into the following three distinct tiers:

The Presence Cluster consists of the following physical nodes:

G.2 XDM Cluster

The XDM cluster is defined as a set of XDM Nodes connected after one or more Load Balancers. The XDM cluster processes all XDM related traffic, that is, SIP subscribe traffic towards the ua-profile event-package and XCAP traffic. As such, it deals with everything that has to do with manipulating XML documents. The XDM Cluster uses a database for actual storage of the XML documents but note that the database, and potentially its cluster, is not part of the XDM Cluster.

The XDM cluster consists of the following layers:

The XDM Cluster consists of the following physical nodes:

G.3 Presence Node

The Presence Node is the main component in the Presence Cluster and is responsible for dispatching the incoming traffic to the correct Presence Server instance and servicing users with presence information. The User Dispatcher servers the same purpose both in a single node deployment and in a multi-node deployment, which is to dispatch incoming traffic to a particular Presence Server instance; whether or not the target Presence Server instance is on the same physical node as the User Dispatcher is of no significance to the User Dispatcher.

A Presence Node will always have a User Dispatcher deployed that serves as the main entrance into the node itself. Typically, the User Dispatchers listen to port 5060 and the Presence Servers on that node listen on other ports. In this way, a single node will appear as one Presence Server to clients but is in fact multiple instances running behind the User Dispatcher. Each of the components deployed on the Presence Node is executing in their own separate Java Virtual Machine. That is, the User Dispatcher and the Presence Server instances execute in their own OWLCS and SIP containers. The reason for this is to be able to utilize all the available memory on that machine.

G.4 XDM Node

The XDM Node always has an Aggregation Proxy deployed that typically listens on port 80 for XCAP traffic. The Aggregation Proxy authenticates incoming traffic and upon successful authentication forwards the request to the User Dispatcher. As with the Presence Node, the XDM Node will also have a User Dispatcher deployed (usually on port 5060) and for SIP traffic there is no difference between the XDM and Presence Nodes. The difference between the two types of nodes is that the User Dispatcher will also dispatch XCAP traffic. As it does with SIP, it extracts the user id out of the request and, based on that, maps the request to a particular XDMS instance to which it forwards the request.

There will be a number of XDMS instances deployed to which the User Dispatcher dispatches both SIP and XCAP traffic. Just as in the case of the Presence Server instances on the Presence Node, each XDMS instance is not aware of the others and executes in isolation.

G.5 Complete Presence and XDM Cluster

Figure G-1 shows a complete Presence and XDM cluster with all necessary components. This figure also illustrates that the two clusters, Presence and XDM, are treated as two separate clusters and the way into those two networks for initial traffic is always through their respective Load Balancers. Even the Presence Servers will actually go through the Load Balancer of the XDM Cluster when setting up subscriptions. However, once a subscription has been established the subsequent requests will not go through the Load Balancer but rather directly to the XDMS instance hosting the subscription. All nodes in the XDM Cluster are directly accessible from the Presence Cluster.

Figure G-1 Presence and XDM Nodes

two node cluster
Description of "Figure G-1 Presence and XDM Nodes"