The WS-ReliableMessaging specification, which was published by IBM, Microsoft, BEA and Tibco, defines a protocol for ensuring that unreceived and duplicate messages can be detected, and received messages can be processed in the order in which they were sent. IBM, Microsoft and BEA published WS-Addressing, which is "a piece of infrastructure that will enable bidirectional, synchronous and asynchronous" Web services messaging, Norsworthy said. And it supports transmission across networks, including across end-point managers, firewalls and gateways, the companies said. "Microsoft, IBM and Tibco are presenting a separate specification effort that differs from the OASIS spec in that it attempts to solve the issue of reliability along the whole end-to-end conversation of a Web service interaction including orchestrated steps across composite Web services that may traverse many different intermediate points and protocols," said Ron Schmelzer, an analyst with ZapThink LLC, a Cambridge, Mass., research firm. "Imagine a SOAP [Simple Object Access Protocol] request hopping from HTTP to MQ Series to a proprietary bus and back to HTTP and guaranteeing the reliability of that whole process. My guess is that they want to bolster the SOAP headers with reliability specifications that will persist with the message, rather than be applicable for particular end points. As part of this, supposedly, they will be providing a spec that doesnt require acknowledgement messages to be sent to each participating end point, but rather either succeed or fail reliably."John Kiger, director of Web services at BEA, said: While both specifications aim to address the need for reliable messaging services, they differ significantly in implementation specifics. For example, the WS-ReliableMessaging and WS-Addressing specifications cleanly separate the issues of reliability from asynchrony, and also define how to specify the policies for a Web service that describe the capabilities and requirements for the messaging associated with that service." As for where the specifications will wind up, he added, "We are currently evaluating a number of options for working within various industry standards groups. Our goal is to create a widely adopted, open, royalty-free reliable messaging standard." Search for more stories by Darryl Taft.
Find white papers on Web services.
"[Competing standards] could not be a good thing for the widespread adoption of Web services," Schmelzer said. "Just as usage of Web services is taking off, vendors are pulling customers in different directions by encouraging them to support open standards that conflict with each other. The WS-I [Web Services Interoperability organization] has to step in here, in our opinion, to take control and start to establish a way in which specifications can be reliably implemented. This is only going to get worse. The process standardsorchestration, composition, transaction, flow and business processare very complicated, and well probably see a zillion different "open" specifications in this area. In fact, the term open is rapidly becoming meaningless. Who cares if a spec is open if there are a dozen other open standards just like it competing for the attention of customers? What clearly is needed is not open but truly standard. I dont know if were going to see that soon in the Web services space in 2003."
Find white papers on Web services.