WS-I Publishes Guidelines To Enable Web Services Interoperability

The guidelines, published Tuesday by the WS-I, are known as Basic Profile 1.0 and define how developers should implement key Web services specifications such as XML and SOAP. The Web services specifications addressed by Basic Profile 1.0 include SOAP 1.1, WSDL 1.1, UDDI 2.0, XML 1.0 and XML Schema, according to the WS-I.

This fall, the WS-I is also slated to deliver a suite of testing tools and sample applications in both C# and Java that can inspect and determine whether a Web service meets the interoperability test.

On Tuesday, the leading WS-I players--including Microsoft, IBM, Sun, Oracle and Bow Street--are expected to gather to announce plans to support Basic Profile 1.0 in future products.

Microsoft, for its part, said its recently released Visual Studio .Net 2003 and the included .Net framework in general already support Basic Profile 1.0. Sun's latest version of the Java Web Services Developer Pack includes a WS-I BP testing tool that verifies that an application conforms to WS-I Basic Profile, according to analyst Anne Thomas Manes, vice president and research director at the Burton Group.

One Microsoft Web services executive and WS-I participant called the release of Basic Profile 1.0 a watershed event in the evolution of the nascent Web services market.

"This is the first milestone for the organization, and [guidelines for] security will follow next," said Steven VanRoekel, director of Web services marketing at Microsoft. "We take existing specs from the W3C, OASIS and others and provide guidelines to help ensure interoperability."

VanRoekel said the Web services specifications generated by W3C, OASIS, UDDI and other organizations leave ample room for different interpretation and implementations, and that "more than 200 interoperability issues were addressed" in the published guidelines.

At the conference, WS-I participants are expected to demonstrate interoperability among nine different vendors' Web services software to prove that the Basic Profile works.

Industry observers have been skeptical that Web services developed using competing technologies and authored by different organizations will play well together without conflict. Burton Group's Manes applauded Basic Profile 1.0 as a good first step but noted that more work needs to be done to ensure that more advanced Web services and distributed applications work together.

"The SOAP 1.1 and WSDL 1.1 specifications contain a number of ambiguities, inconsistencies and errors. These ambiguities leave the specifications open to interpretation, and not all vendors interpret them the same way," Manes said. "If developers build services within the guideline defined by the WS-I BP, those services should be interoperable. Interoperability has been pretty challenging, and the [guidelines] will make interoperability much easier. And interoperability is the raison d'etre of Web services. All in all, WS-I Basic Profile is a very good thing for customers."

However, she noted that the Basic Profile enables interoperability only among simple Web services and that the WS-I is working on security, reliability, transactions and orchestration guidelines for more complex applications.

"By solving this problem, we're likely to see wider adoption, of Web services," Manes said.

Another analyst agreed that the Basic Profile will lead to Web services interoperability but pointed out that there remains room for vendors to implement some of the specifications differently.

"Overall, the release of the profile, and its support by most of the major vendors, will cause WS-I compliance to be a requirement for most buyers when purchasing SOAP-enabled technology," said Daniel Sholler vice president of technology research services at Meta Group. But "there are areas that the WS-I does not address--and does not claim to address--so there will be a place for SOAP-based technology that is not WS-I compliant," he said.