Interoperability is key to Web services

Can the problem of interoperability be addressed to make Web services work for business? Users and suppliers have united to form...

Can the problem of interoperability be addressed to make Web services work for business? Users and suppliers have united to form a body charged to make it possible

Last month saw an impressive gathering of the great and good in the world of Web services - the technology that will allow applications to interact over the Internet. Key suppliers such as IBM, Intel, Microsoft and Oracle, joined forces with user giants Daimler Chrysler, Ford Motor Company, Reed Elsevier, Reuters and United Airlines to create the Web Services Interoperability Organisation (WS-I).

Interoperability, or lack of it, is an issue that dogs many promising technology developments. Since the IT industry seems to have only recently addressed the problem of sharing word-processing files across different systems, interoperability is vital if the Web services concept is ever to produce practical benefits for businesses.

IBM and Microsoft have worked for some time on a common model for Web services interoperability (called the "Web Services Framework"); the WS-I is their attempt to broaden support for their effort.

Although Sun, which invented Web development language Java and manufactures popular Web server technology, has been hesitant to join the WS-I, the signs are that it will join in time - and this can only be a good thing.

So what exactly does WS-I plan to do? The good news for users is that WS-I is not aiming to define standards. The organisation's members are clear that defining standards is the role of the Internet Engineering Task Force, Organisation for the Advancement of Structured Information, the World-Wide Web Consortium and others.

WS-I will focus on ensuring the interoperability of suppliers' implementations. This is fundamentally different in practice. WS-I intends to do this by creating "profiles", which group together sets of complementary standards - and using these profiles as the benchmarks for testing.

The concept of working with profiles, rather than with individual standards, is a sensible one, because they work at a higher level that corresponds much more closely to the way that standards such as Soap, WSDL (Web Services Description Language) and UDDI will be used in real-world projects. The WS-I members are splitting into a number of working groups, each of which will focus on building sample Web services implementations which demonstrate the technology at work in a truly interoperable, cross-supplier environment.

This is where the value of having IT users in the organisation comes to the fore. Without the input of leading-edge users such as Ford, Reuters and United Airlines, the implementation scenarios would probably be neither representative nor real-world - and the WS-I would be just another talking shop. With their presence and input, the sample implementations stand a good chance of helping to educate other user companies, and software suppliers.

This is a great start - but we are looking to WS-I to do more. Successful Web services will depend on the establishment of vertical trading agreements within industries. They will also require interoperable technology implementations within companies. The profile mechanisms used by WS-I will provide an ideal vehicle - but trading agreements will not be forged without the active participation of representative user organisations to drive it. The involvement of user organisations in WS-I is encouraging, as is the membership of the standards consortium POSC from the energy industry.

We would like to see much more widespread vertical market support from enterprise users and other industry bodies, such as RosettaNet, which was set up to standardise interfaces for electronic commerce between supply chain partners. Given global e-government initiatives and the role of regulation, it will be interesting to see whether they become members. These players should be at least closely monitoring WS-I's activities.

WS-I is a great addition to the fledgling Web services technology industry. It is not just a noise machine, although we are a little surprised and concerned that authentication and authorisation are not referenced, despite the existence of Passport, the Liberty Alliance and emerging standards such as SAML (Security Assertion Markup Language). Other omissions include workflow, business process management, and synchronous and asynchronous transactions. Alongside Java and .net, these are - or should be - critically important to users looking to start building and deploying Web services.

So, given that WS-I is so important, what must it do to thrive? First, it must avoid appearing to dictate and direct standards initiatives, while also playing the role of diplomat and arbiter when dealing with overlapping standards under the control of different standards bodies. This is particularly important and tricky because WS-I is dependent on the responsiveness of the standards bodies. The World- Wide Web Consortium is yet to establish a Web Service Definition Language working group - a year after the publication of the original specification.

WS-I must also quickly win consensus among traditional competitors with vested interests in driving the standards to meet their own needs. Interoperability will increase the size of the Web services pie and will help to drive co-operation but WS-I must not underestimate the politics involved.

Who's who in WS-I?

Accenture, BEA Systems, Fujitsu, HP, IBM, Intel, Microsoft, Oracle, SAP, Autodesk, Cape Clear, CommerceOne, Compaq, Groove Networks, Jamcracker, Plumtree, and Verisign

Daimler Chrysler, Ford Motor Company, Reed Elsevier, Reuters and United Airlines

Neil Ward-Dutton is research director at Ovum

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