The Microsoft Exchange Server 5.5 routing objects and routing engine handle the process of guiding a document to a sequence of destinations, using server-side administration of the document's progress. Server-side administration was chosen to ensure that the document doesn't languish at a client computer that may not be responding, for reasons technical or personal. The routing engine manages the state and state transitions of the route of a message being routed between participants.
Note The Microsoft Exchange Server routing engine requires that the Microsoft Exchange Server Event Service be running.
You control routing by using a routing map, which is a low-level description of the logic involved in the route. Within such a map, a task such as "Get Administrator's Approval" is broken down into its basic logic and functions. Routing maps contain two kinds of activities, those for flow control, which are implemented by the routing engine, and evaluation and functional activities, which are implemented in VBScript.
Exchange Server 5.5 Service Pack 1 and Service Pack 2 include a Routing Wizard, which is a simple authoring tool that can be used to create short sequential and parallel routes. The source code is included on the Service Pack CD. The wizard creates a route and saves it to a folder, so that any message posted or sent to this folder is routed according to the map. For a more in-depth description, see the article, "The Routing Problem: The Microsoft Exchange Server Solution" at http://msdn.microsoft.com/library/techart/msdn_exchrout.htm.