The XML Web Services One conference featured a panel of Web services experts from a variety of companies demonstrating interoperability in a basic scenario prepared for the conference.

Prior to the conference, the SOAP Interoperability group prepared the demonstration scenario, starting with a WSDL specification developed by Tony Hong. The scenario was e-commerce involving the customer, warehouse and credit institution actors.

The various panelists developed systems based on this scenario and the given WSDL, using a variety of toolkits. The conference featured a panel of the participants as well as demos of the resulting systems at the participants' booths in the exhibit hall, each talking to the others over the local network.

The panel had Tony Baer of On Strategies, Inc. and Application Development Trends as moderator. The panelists were Norbert Mikula (Intel, WS-I, OASIS), Scott Seely (Microsoft), Sam Ruby (IBM, Apache Software Foundation), Rebecca Dias (Iona), Jim d'Augustine (Excelon) and Tony Hong (XMethods).

According to the panelists, the goals of the project were: "To show that inter-vendor messaging works today" and "To demonstrate the benefits of a WSDL-first approach".

Early on in the session, Baer asked how many people in the audience were using WS technologies in application development. About 30 percent of the audience of 120 or so raised their hands. A follow-up question was: of this number, how many used Web service externally, as opposed to within the firewall? To the surprise of the panelists, about 75 percent of those who said they were already using Web services raised their hands to indicate that they were doing so outside the firewall.

The panelists seemed to go out of their way to stress that they were trying to prove document-oriented Web services. They also stressed that they made sure they had to deal with highly asynchronous transactions.

The panelists also claimed that interoperability was very good: problems were relegated mostly to incidental technical glitches. Sam Ruby did point out that since they started out with WSDL, a lot of the hard part (interface definition) was done for them. When asked the level of effort for the implementation, most panelists said it involved one developer over a day or two. One panelist said it took close to ten man-days.

In one lively exchange, Scott Seely said that in every Web services team at least one "superstar" is needed, not necessarily a Web services expert, but one who knows all aspects of XML: WXS, XPath, etc. Such expertise is needed to deal with inevitable problems related to the rich messaging. Rebecca Dias violently disagreed, saying that such things were a matter for the toolkit to automate for the user. This seeming contradiction between respect for document-oriented messaging and reliance on toolkits was the subject of a modest debate on the panel and among the audience.

This conference was the first in which the interoperability demo was presented, and the demo shall also be present during exhibits at the XML Web Services One conference in Boston.