BEA, Intalio, SAP and Sun advocate a drop of WSCI

It's designed to describe the behavior a developer can expect from a Web service and it has potential, but the451 believes WSCI's success or failure won't be determined by how good the technology is, but by who supports it.


The battle for the layers above the relatively established core Web services standards has a new player in the form of a standard proposed by BEA, Intalio, SAP and Sun.

It's called the Web Service Choreography Interface (WSCI, pronounced like the drink) and it is meant to help track the sequence of messages, logical dependencies and exception handling that will occur when applications are made up of multiple Web services from potentially multiple sources. Put simply, it describes the behavior a developer can expect from a Web service by interacting with it.

Given the number of competing would-be standards and the amount of noise in this space, it is equally important to say what WSCI is not, in addition to defining what it is. It is not a specification to dictate the assembly of composite Web services applications, nor is it a high-level workflow specification, nor something to define a gateway. In the words of the specification description itself, it is concerned solely with the "observable behavior" of a Web service, not the process by which it was created.

Technology: WSCI builds upon the Web Services Definition Language (WSDL), which defines the interface a Web service presents to other applications and, along with SOAP, comprises the two core standards upon which Web services are being built. WSCI adds to this by giving a picture of the types of messages, their sequence and other attributes that need to be determined to enable applications to successfully interact with each other.

Currently, such things are handled well by enterprise application integration tools from the likes of IBM, Tibco and webMethods. But besides that fact that they are proprietary to each vendor, they are not suitable in an environment where there is not a central hub through which all messages between applications must pass, and thus can be logged and checked that they are in the correct order and of the same type and so on.

That information needs to be contained within the Web service itself. The loose coupling of Web services is one of the things that makes it different from pervious efforts to make applications talk to each other. The closest thing to WSCI from the days of Corba is probably the OMG's Enterprise Distributed Object Computing (EDOC) initiative.

Other standards: WSCI is meant to work at a layer below – or alongside, depending on how you look at it – the various would-be business process management standards, such as the Web Services Flow Language (WSFL) being pushed by IBM and its rival XLANG, which originated at Microsoft.

There is a third major business process language initiative, called Business Process Modeling Language (BPML), written by the Business Process Management Initiative (BPMI), which was founded by Intalio. The BPMI published version 1.0 of BPML this week. Sun says that whereas BPML is a scripting language meant to be used with an engine that executes the workflow, it does not prescribe how the engine interacts with other applications, which is where WSCI comes in. And UDDI doesn't do this either, merely acting as a 'yellow pages,' but Sun can see the day when WSCI might end up as part of UDDI, if that takes off.

According to Sun, this standard emerged from the various firms' research departments and was not something imposed from the top down, which it believes gives it more credibility with those that will eventually work on it and with it, both in the standards organizations and in software development teams.

To explain the choice of names, Sun says this is choreography, not orchestration. The former implies everybody dancing the same steps, the latter implies one person leading from the front and everybody else falling in line.

Competition: As with all standards, WSCI's success or failure will not necessarily depend on how good the technology is, but who supports it. And while the three major vendors here are a good start, the group knows it needs much wider support. As the451 has been illustrating for some time, this typically involves IBM and Microsoft setting the pace and others following.

However, with Sun's adoption of the IBM and Microsoft-led WS-Security format this week and now this attempt to recapture its earlier reputation for defining standards – with Java being the shining example – BEA and Sun at least have a stake in the ground in what will be a very important area in determining the success or failure of Web services.

For its part, IBM considers WSCI to be a subset of BPML, which has been around for a couple of years. It says that while it is still early on in the workflow and business process languages space, it believes the industry will consolidate within 6-12 months around a unified standard, at least in a draft form. If that timetable is accurate, of course, it doesn't give WSCI a whole lot of time. Following a public comment period driven from the four companies' websites, the group says they intend to submit WSCI to a standards organization on a royalty-free basis. Although Sun would not indicate its preference, the favorites would seem to be OASIS or the W3C.

Products: Intalio, which first launched two years ago, is gearing up to relaunch soon with WSCI as part of its five-piece n3 business process management implementation, but details are scarce right now. Sun is about to release a free WSCI editor for developers.

Assessment: From what is currently known, WSCI seem more broadly applicable than the prospective BPM and workflow standards. It is a chance for BEA and Sun to reclaim some of the standards-defining high ground from IBM and Microsoft. However, IBM and others that are not behind this yet could use the similarity between aspects of WSCI, WSFL and XLANG as a reason to not bother supporting it and in doing so, attempting to freeze out Sun once more. Until some of the three large companies here implement it, WSCI's credentials will be doubted.


the451 is an analyst firm that provides timely, detailed and independent analysis of news in technology, communications and media. To evaluate the service, click here.

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