Microsoft has started pushing its own BizTalk above the increasingly popular ESB (enterprise service bus) Web services technology.

A new paper by the software giant states explicitly that it is positioning its BizTalk Server integration and process server and its planned Indigo Web services technology against ESB. Microsoft doesn't believe ESB is a standalone product category but "customers looking to purchase an ESB will find that Microsoft offers a significant superset of ESB functionality," the company said.

An ESB does not meet all the needs of users, said Scott Woodgate, co-author of the paper. "We don't believe that customers will benefit significantly from the ESB products," he said.

Usually viewed as a mechanism to provide Web services-based application integration in SOA environments, companies such as Sonic Software, Cape Clear Software, and, as of early this month, BEA Systems, are offering ESB. But Microsoft characterises an ESB as ambiguous. "The recent buzz around ESB is rivalled only by the ambiguity by which the term is defined," Microsoft says in the paper.

BizTalk Server 2004 enables decoupled integration with a range of systems, including MQSeries, SAP systems, and Web services, according to Microsoft: "BizTalk Server provides for all the capabilities of traditional ESBs." Business activity monitoring and other related functions also are provided.

Indigo, which is now officially being called the WCF (Windows Communication Foundation), is Microsoft's next-generation Web services technology. It offers a framework for secure, reliable and inter-operable software based on industry standards, Microsoft said.

"I think the key thing from a Microsoft perspective is that customers are looking to integrate applications inside their enterprises, customers are looking for vendors to provide solutions all the way across the stack," Woodgate said. Customers want business process infrastructure, connection of applications and business activity monitoring, but an ESB only includes the messaging infrastructure, Woodgate said.

Although there is no industry-standard definition of an ESB, general characteristics include brokered communication, address indirection and intelligent routing, and basic Web services support, according to Microsoft. Some ESB vendors also offer message transformation, validation, logging, and auditing.

Microsoft with WCF will offer a superior alternative to an ESB, one analyst said. "Fundamentally, what Microsoft is putting together is much better than an ESB," said Jason Bloomberg, senior analyst at ZapThink. "Basically, WCF is a quantum leap above ESB - it's essentially a framework for building a whole range of different tools, including ESBs. So yes, the combination of WCF and BizTalk does much of what today's ESBs do, but that undersells the power of Microsoft's vision and technology, especially as they move to the Vista wave."