A new specification defining reliable messaging for Web services, authored by BEA, IBM, Microsoft, and business integration software company TIBCO, has been released. WS-ReliableMessaging aims to bring message queuing capabilities to Web services, although differences between it and a competing specification called WS-Reliability developed by Fujitsu, Oracle, and Sun Microsystems must be ironed out in order to achieve broad interoperability among vendors.

Reliable messaging is the ability to guarantee that a message will be received by its intended recipient one and only one time, even if the recipient is temporarily offline or if the network connection between sender and recipient is intermittent. Technologies such as Microsoft Message Queuing (MSMQ) and IBM’s MQSeries (recently renamed Websphere MQ) provide this capability for internal business systems, but not across Web services. WS-ReliableMessaging is part of Microsoft’s Global XML Architecture (GXA)—a broader initiative to address some of the limitations of Web services that make them difficult to use for large-scale, line-of-business applications. Like the previously announced WS-Transactions and WS-Security, WS-ReliableMessaging takes a technology already understood and used in corporate applications and applies it to Web services.

While the competing WS-Reliability initiative has been submitted to the Organization for the Advancement of Structured Information Standards (OASIS) for standardization, Microsoft and its partners have yet to announce the standards body they will submit WS-ReliableMessaging to. They do claim, however, that WS-ReliableMessaging, unlike WS-Reliability, was designed to operate well with other draft specifications, such as WS-Security, but because interoperability between operating systems, platforms, applications, and tools is a key requirement for Web services, any squabbling among vendors risks slowing the adoption of Web services in general.

A joint IBM-Microsoft white paper on reliable messaging is at msdn.microsoft.com/library/en-us/dnglobspec/html/ws-rm-exec-summary.asp.

The complete specification for WS-ReliableMessaging is at msdn.microsoft.com/ws/2003/03/ws-reliablemessaging.

For more information on GXA, see "GXA Defines Framework for Web Services" on page 11 of the Oct. 2002 Update.