Message Queuing Routing

Applies To: Windows Server 2008

Routing overview

A Message Queuing client always tries to establish a direct connection, or session, with the destination computer using the underlying IP network protocol. If a direct connection is not possible or not allowed, Message Queuing servers with routing enabled (routing servers) can temporarily store messages and subsequently forward them to the destination computer or to another routing server. In this way, they establish the route taken by messages as they proceed from the source computer to the destination computer. Specifically, message routing can occur when one or both of the following conditions exist:

  • A session cannot be established between the source computer and the destination computer (for example, if the destination computer is offline).

  • Specific Message Queuing routing servers are designated to store and forward messages on behalf of the source or destination computer.

Message routing can only be performed when the destination queue is opened using PUBLIC or PRIVATE format names. For more information about public and private format names see Queue Names.

Message routing between networks

Message Queuing can be used to send messages to and receive messages from external networks, such as other organizations or other Windows ServerĀ® 2008 family forests. Message Queuing computers can use various service ports to communicate with external networks through properly configured firewalls that allow communication over those ports. For more information, see Internet Messaging Overview.

Although clients within a site that use the same network protocol are assumed to have direct connectivity, using in-routing and out-routing servers to route messages within a site may reduce the bandwidth requirements in your network. Clients can be configured to use in-routing and out-routing servers to provide message routing on their behalf. In that case, all messages sent or received by a client are routed first through such a Message Queuing server. The term client here refers to any Message Queuing computer that cannot route messages on its own, such as independent clients and Message Queuing servers without routing enabled. This feature is not applicable to dependent clients. Dependent clients require a supporting server to send and receive messages on their behalf. A supporting server without routing enabled, rather than its dependent clients, can be configured to use in-routing and out-routing servers.

If site gates are used to route messages between sites, only those assigned Message Queuing servers can route messages between the sites.


Message routing is not applicable in a workgroup environment. Thus, in-routing servers, out-routing servers, and site gates cannot be used, and direct connectivity between the source and destination computers is required.

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