XML One	Volume 4 Number 2 July 3, 2000	RealAudio

by Scott Tilley

Attending the XML One conference in Austin a few months ago was very enlightening. Given the huge role XML (and SOAP) plays in Microsoft's recently announced .NET initiative, no one can afford to ignore new developments in the XML world. The XML One conference provides a singular perspective on an important and rapidly developing technology, a perspective that's not really available anywhere else.

The Extensible Markup Language (XML) has been touted as the "next big thing" for the Web, and indeed it does hold the promise of substantially changing the business landscape. XML is like HTML's big brother, but it's far more than just another markup language. The "extensible" part of its name refers to the essential difference between HTML and XML: in XML, you create your own tags. This seemingly simple change from HTML has created a lot of excitement in the information technology world.

To see what the excitement is all about, I attended the XML One conference in Austin last March. The XML One conference is held twice a year in the US, and twice a year in Europe. The Texas event attracted about 450 paying attendees. There was the usual collection of tutorials, paper presentations, and vendor exhibits. To my mind, two significant items emerged from XML One: business-to-business (B2B) integration and SOAP.

B2B Integration

Integrating data from heterogeneous sources is one of the biggest challenges facing businesses as they move online. It's also an area for which XML is eminently suited. By creating a shared schema, realized as a Document Type Definition (DTD), different applications and different vendors can share information. Indeed, several companies at XML One demonstrated tools to convert legacy data into XML for use on the Web. 

One such company is Data Junction. As described in the company's literature,

Data Junction leverages a hub & spoke architecture to act as a universal and neutral "junction" for all structured data. The "hub" is a robust transformation engine. The "spokes" are Data Junction's unique interfaces that reach out and connect to hundreds of data formats.

The Data Junction product is one of the most popular tools for integrating legacy data from multiple sources. However, it is not the only one available. Many other vendors were exhibiting similar products. Indeed, some of the companies that I interviewed portrayed themselves as XML-focused at the conference, but I know them better for other products. For example, I'm familiar with Scriptics because of their Tcl/Tk scripting software, but they recently changed their name to Ajuba Solutions and now focus on B2B integration using XML. Similarly, I know Rogue Wave Software for their C++ class libraries, but at XML One they were focusing on their XML-CORBA Link product that provides a consistent XML access layer to leading ORBs.

SOAP

While XML provides the messaging format for B2B integration, there still needs to be a medium or a protocol used to exchange XML documents. This is where the Simple Object Access Protocol (SOAP) comes in. SOAP can be characterized as a providing a way for distributed object services to interact using plain HTTP. When this simplicity is contrasted with the complexity required for other similar services, such as CORBA or Java RMI, the allure of SOAP becomes apparent.

However, this simplicity is not without cost. Perhaps its most serious shortcoming is related to security. By transmitting data using HTTP, SOAP is essentially providing a tunnel through corporate firewalls. Most firewalls let HTTP traffic pass through, because it is assumed that the data requests are fairly innocuous, while blocking service requests on other ports. When SOAP is used, however, the data that passes through the firewall gets stripped of its secure envelope to reveal potentially damaging code. This is similar to the way the Point-to-Point Tunneling Protocol (PPTP) works, except that in the case of PPTP only communications traffic such as telnet sessions is usually transmitted. With SOAP, arbitrary data access, program execution, and scriptable services can be launched.

If I had to pick one development that I think has a good chance of making a significant impact on business, it would be XML using SOAP. This type of "XML on the wire" application has a strong attraction because it relies on simple, standard, and available technology. Several speakers at XML One stated that XML messages may soon become the key substrate of application integration.

Final Comments

As a commercial gathering, attending XML One can be a rather expensive undertaking. However, there are quite a few new and interesting developments that are only available at this event. Since many of the conferences I usually attend are academic in nature, it was very interesting to experience a more commercially-oriented event. XML One provides a singular perspective on an important and rapidly developing technology, a perspective that's not really available anywhere else.