MOSS 2007 Shared Service Provider (SSP)

Shared Service Provider. This is a collection of application servers that provide shared services out to any portals or sites that need them. These services include:

• Search
• Index
• Audience compilation
• User profiles database
• My Sites
• Business Data Catalogue
• Excel Services

Any of the above services can exist on any number of servers on SSP except Index service, which can only have one per SSP. SSP has no affiliation to portal. In MOSS 2007, portal (web application) is just a site collection with no application services inside. All the application services will be provided by SSP.

It's possible to create two different SSPs within the same server farm, each with its own configuration. Within a MOSS 2007 farm, each Web application is associated with exactly one SSP.

Reference: MOSS Architecture and Shared Services