When designing your Communications Services deployment architecture, take into account the requirements of the various component products of your deployment. For example, if you have a technical requirement to integrate Communications Services with other Java System products, you need to choose your schema accordingly. Inter-product dependencies, for example, how Communications Services access and place load on Directory Server, present deployment choices as well.
Understanding the individual components of each product enables you to plan for the type of architecture to best suit your requirements. Depending on your deployment, you need to potentially understand and plan for the following components:
LDAP Directory Information Tree
Directory Server (Access Manager)
Message Transfer Agent (MTA)
Messaging Multiplexor (MMP)
Messaging Express Multiplexor (MEM)
Instant Messaging Proxy
Instant Messaging Back End
Connector for Microsoft Outlook
When planning a Communications Services deployment for multiple component products or services, you need to understand the composition of each component product (or service) itself.
Figure 3–1 illustrates how you can separate each service into components that can be deployed on separate hosts, and the particular tier each component occupies. Though you can deploy all components on a single host, or deploy a particular service’s components on the same host, consider moving to a tiered architecture. A tiered architecture, whether it be single-tiered, or two-tiered, provides a number of benefits. See Benefits of a Single-tiered Architecture and Benefits of a Two-tiered Architecture for more information.
In the preceding figure, the client components consist of the Outlook Connector plugin, thick clients such as Evolution, browsers, and standard email applications. These components reside on end users’ client computers. The access layer components consist of front-end services from Messaging Server (MMP, MTA, and MEM); Calendar Server; Communications Express (which must be collocated with MEM); Instant Messaging (Instant Messaging Proxy); Portal Server (SRA and Core); Access Manager for authentication; and a corporate directory, which provides address book lookup. The data layer components consist of back-end services from Directory Server (which, in itself, can consist of front-end and back-end components); Messaging Server (Message Store); Calendar Server (Calendar Store); and Instant Messaging. A Storage Area Network (SAN) “cloud” represents the physical data storage.
The corporate directory shown in this figure is not a component product in itself. It represents a “copy” of the corporate directory that enterprises typically deploy in the access layer for clients to perform address-book type lookups.
The following sections explain these various components in more detail.