Applies To: Windows Server 2008
Message routing within a site is called intrasite routing. In the simplest case, the source and destination computers are not configured to use in-routing or out-routing servers. In this case, as a first choice, Message Queuing tries to deliver a message to the destination computer directly (one hop), and as a second choice, it delivers the message to one randomly chosen Message Queuing routing server that resides in the site (two hops).
This diagram shows one possibility for routing a message from one computer to another computer within a site. Although the number of hops can vary, here, a message sent from one computer in the site to another computer in the same site makes two hops: one hop to get to the Message Queuing routing server and one hop to get to the destination computer. Because each hop is within a site, the performance overhead of each hop is minimal.
In-routing and out-routing servers
In the context of intrasite routing, independent clients and Message Queuing servers without routing enabled are functionally equivalent. These computers can be configured to use in-routing servers (InRS) or out-routing servers (OutRS) to store and forward messages on their behalf. Dependent clients cannot be configured to use in-routing or out-routing servers because all messaging functions are performed by a supporting server.
If an independent client or a Message Queuing server without routing enabled is configured to use an out-routing server, every outgoing message sent by that computer is routed through that server. Likewise, if such a computer is configured to use an in-routing server, every message sent to it is routed through that server. Such a computer can use the same Message Queuing routing server as both its in-routing and out-routing server.
All in-routing and out-routing servers must be in the original site of the computer that they serve. When a mobile client moves to another site, these servers are not used for message routing until the client returns to its original site.
Intrasite routing can reduce the usage of network bandwidth by providing session concentration. For example, if you use a star topology within a site and each independent client usually communicates directly with all other independent clients, you can reduce your bandwidth usage through session concentration by configuring each client to use in-routing and out-routing servers.
In this figure, the same Message Queuing routing server is configured as both an in-routing server and an out-routing server for each client.