Office Communications Server supports the following three scenarios or workloads: instant messaging (IM) and presence, conferencing (including Web conferencing, desktop sharing, audio/video conferencing), and Enterprise Voice, which encompasses telephony. This section describes all of the architectural components of an Office Communications Server 2007 R2 Standard Edition server or Enterprise pool. Collectively, these components support all three workloads.

This section focuses on the services that run on the core Office Communications Server roles, the components within those services, and relationships between them. This section does not cover network architecture or deployment architecture, which complement component architecture. For details about those aspects of architecture, see the Planning and Architecturedocumentation.

While this section describes components in the context of an Enterprise pool, it also applies to most aspects of a Standard Edition server. All server components (that is, services, database, and so on) described in this section run together on a single instance of a Standard Edition server. This is a typical configuration for simple or relatively small deployments (that is, up to a few thousand users) where high availability is not a requirement.

Conceptually, a pool consists of one or more Front End Servers and one or more databases on the Back-End Database Server with a single SQL Server. In a pool, all persistent states are stored in the database on the Back-End Database Server, so that when a Front End Server component fails, failover can be quick. Figure 1 shows a sample Enterprise pool.

Figure 1. Sample Enterprise pool

Figure 1 illustrates the components of Front End Servers and the Back-End Database Server. There is a hardware load balancer for the Front End Servers, which are required for an Enterprise pool that has more than one Enterprise Edition server. (If your pool consists of only one Front End Server, which is connected to a separate Back-End Database Server running SQL Server, a load balancer is not required.) All Front End Servers in a consolidated configuration pool are homogeneous and identical to each other. Therefore, all relevant Office Communications Server services and applications are installed on all Front End Servers in this type of a pool.

On each Office Communications Server 2007 R2 Front End Server, the main components can be classified as follows:

Each of these classes of components is described in the topics that follow.

See Also