Routing with Message Queuing Servers

Updated: June 25, 2007

Applies To: Windows Server 2008

The number of Message Queuing servers with routing enabled (routing servers) that you deploy in your organization can depend on the following factors:

  • The number of sites among which you are routing messages.

  • How frequently client computers are offline. Message Queuing servers with routing services are needed for message store-and-forward capability when the source and destination computers may not be online at the same time.

It is recommended that at least one routing server be installed in each site to ensure that messages are forwarded successfully. For performance and scalability reasons, it is recommended that multiple Message Queuing routing servers be installed in each site.

A source computer will successfully forward a message to a destination computer when a direct connection is established and when the destination site has no site gate. If the destination site has a site gate, the messages will not be forwarded and will accumulate at the source.

It is recommended that in-routing and out-routing servers be available for mobile clients that are mostly disconnected from the network or connect to the network through a remote access server.

There is no technical restriction or limitation on installing Message Queuing routing servers on domain controllers. However, because the main roles of domain controllers include authenticating users, handling queries to Active Directory Domain Services, and maintaining domain security, it is recommended that you carefully consider how installing Message Queuing routing servers on domain controllers may influence their performance and security.

By providing session concentration, the use of Message Queuing routing servers may reduce operating costs. Such servers can reduce bandwidth needs within a site and reduce the number of sessions between different sites. Intrasite routing is considered relatively fast and inexpensive, while intersite routing is considered relatively slow and expensive.

In addition, when Message Queuing routing servers are available, messages do not accumulate in independent clients, which generally have a small storage capacity, but can be delivered to an out-routing server, which stores them until the destination computer becomes online.

Message Queuing routing servers that provide intrasite message routing are called in-routing servers (InRS) or out-routing servers (OutRS). Message Queuing servers providing message routing on a routing link, which defines connectivity between sites, are called site gates. For more information about intrasite routing, see Intrasite Routing. For more information about intersite routing, see Intersite Routing.

The relative cost of using a given route to reach a destination computer is commonly measured in hops, where each hop represents the delivery of a message from one computer to another. If there are multiple routes with the same destination, the route with the lowest hop count is the best.

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