Routing SOAP Messages Using WSE

A distributed application using WSE can be designed such that the network topology implementing the application is transparent to clients. To set up a transparent network topology, set up an intermediate computer that is configured to run WSE router. Clients then send the SOAP messages to WSE router instead of directly to the Web service. WSE router then delegates the SOAP message to a computer hosting the Web service, which can be changed using a configuration file on the computer hosting WSE router.

Using the WSE Router

One of the benefits of using WSE router with a distributed application is that a computer hosting a Web service can be taken offline for maintenance without modifying either the client code or its configuration. An administrator of the computer hosting WSE router can make all the changes needed to redirect the SOAP messages to another computer. To do so, an administrator prepares a backup computer to be brought online to host the Web service, while the router continues to delegate SOAP messages to the primary computer. Then the administrator prepares a Web.config file that specifies the file containing the referral cache and a new referral cache containing the URL for the backup computer. A referral cache is an XML file that contains the ultimate destination for URLs received by the router. Then, when the primary computer is taken offline, the Web.config and referral cache are placed on the computer hosting the router. Subsequent SOAP messages are then dynamically routed to the backup computer—all unbeknownst to the client application, which is still sending SOAP messages to the router.

The following graphic depicts sending SOAP messages to a WSE router, which delegates the SOAP message to another Web server based on the contents of a referral cache. In this graphic, the referral cache is configured to send the SOAP message to Web server B, but the referral cache could be modified to send it to Web server C.

WSE also supports the forwarding of SOAP messages to their recipients based on information that indicates an alternative route for a Web service. A recipient of the SOAP message can then dynamically route messages according to the referral without the intervention of an administrator. WSE only supports the forwarding of SOAP messages that are not intended for a computer running WSE router.

For more information about how to route SOAP messages using a transparent network topology, see Routing SOAP Messages with WSE.

See Also

Other Resources

Routing SOAP Messages with WSE
Perimeter Service Router
Implementing Perimeter Service Router in WSE 3.0