SharePoint 2007 Enterprise Search Architecture

Enterprise search in SharePoint Server 2007 depends on two main components. An indexing service on a central server crawls enterprise data resources and builds full-text indexes to speed search. Query servers allow users to conduct searches. (In small-scale deployments, the indexing and query server can be combined on a single machine.)

Out of the box, the SharePoint Server 2007 indexing service reads data from more than 200 types of sources, including SharePoint sites, HTML pages on other types of intranet sites, files on file servers, Exchange Public Folders, and Lotus Notes databases. The service can be extended to index more data types by installing additional iFilters, which are usually written by third-party ISVs or partners. A separate technology known as protocol handlers lets the indexing service retrieve data over different types of connections, such as the Hypertext Transfer Protocol (HTTP) or the File Transfer Protocol (FTP). The Business Data Catalog service, available in the full version of SharePoint Server 2007, integrates data from business applications (e.g., an ERP application) into SharePoint Server 2007, allowing the indexing service to index data from these applications without requiring custom iFilters or protocol handlers.