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A Standard For Integrating Standards

A Web-services standards group has filled in some of the holes with a new standard for integrating common functionality.
In an attempt to make Web-services interactions more predictable, the Web Service Interoperability Organization on Tuesday released its Basic Profile 1.0, defining how existing standards should be implemented if the goal is to have them work together.

The move joins in common purpose--temporarily at least--IBM, Microsoft, and Sun Microsystems. IBM and Microsoft have joined forces in the past to establish the Simple Object Access Protocol for exchanging XML documents over the Web. The Basic Profile describes acceptable use of Soap 1.1. Sun has been aligned with IBM on most Java initiatives but has warred with Microsoft over its Java implementations and other Windows-oriented standards and competes with IBM on transaction-oriented standards.

The Web Service Interoperability Organization was created in April 2002 at the impetus of IBM and Microsoft. Sun wasn't offered a position on its board of directors when it was founded, says Robert Sutor, IBM's director of WebSphere infrastructure software, because Sun "up until that point had said Web services were a bad idea."

Sun executives, however, said in response to the formation of WS-I that it wished to be on the board and questioned how a group devoted to Web services could exclude the leading Java proponent. In March, the organization held an election, and Sun and integration-software vendor webMethods Inc. were elected as members of the board. "We are a standards integrator, not a standards producer," says Tom Glover, chairman of the group.

WS-I set up a Basic Profile working group to hammer out agreement on how existing Web-services standards could work together. Their focus was Soap 1.1; Web Services Description Language (WSDL) 1.1 for describing Web services; Universal Description, Discovery, and Integration (UDDI) 2.0, for building directories of Web services; XML 1.0 for generating interchangeable documents; and XML Schema for setting document formats. All the existing standards contained "wiggle room" left by their originators as matters of choice for implementers. "Two people reading the same standard could choose different ways to implement it, and the results would not be interoperable," Glover says.

The Basic Profile defines the ways to implement Soap, UDDI, WSDL, and XML, if you want your software to work with other software available on the Web, he says. "Where there were cracks in the standards, we filled in those holes as well," he adds.

As developers follow the Basic Profile, more and more interoperable software will become available on the Web, and vendors' tools will be geared to produce Basic Profile-compatible software, says Chris Ferris, chairman of the Basic Profile working group and senior technical staff member in IBM's Emerging Technology Software Group.

When it came to Soap, for example, Ferris says the Soap standard allowed a Soap document to consist of an envelope, a header indicating where the message should go, a body that would include the document itself, and then left open the possibility that some other XML content would follow the body. In the Basic Profile, the body is the last part of the document and no additional elements may be added, Ferris says.

In formulating the profile, the working group tried to follow "those practices that have most predominantly been adopted. We tried to settle on what the common industry practice was," he says.

The interoperability that results from following the Basic Profile is being demonstrated by the likes of IBM, Microsoft, SAP, and Sun at the Web Services One Conference in Boston this week. "We resolved over 200 issues in WSDL, UDDI, and XML," says Sinisa Zimek, director of technology, strategy, and standards at application vendor SAP. The result is that applications produced by all four vendors work with each other over an IP network without knowing very much about each other, he says. Zimek is a member of the WS-I board.

The Basic Profile "establishes a set of guidelines and best practices to insure interoperability," says Alan Davies, VP of standards at SeeBeyond, an integration software vendor.

In addition, the WS-I released preliminary versions of tools for testing an application to see whether it follows the Basic Profile recommendations. Copies of the tools and Basic Profile are available here.

The WS-I is made up of 170 vendors, including BEA Systems, Bowstreet, CapeClear Software, Eastman Kodak, Fujitsu Software, Hummingbird, Oracle, SAP, and the SAS Institute.