Columns

Cleaning up E-Business

• By Stephen Swoyer
• 09/01/2001

But what is SOAP? And why should you care about it?

SOAP is based on XML, which is commonly used to define data elements on a Web page and in other documents. Sound a lot like HTML? Not necessarily: Although XML uses a tag structure that resembles HTML’s structure, the similarities end there.

For example, XML tags can define what kinds of content data elements actually contain, while HTML tags, conversely, define the manner in which data elements are displayed. And developers can also use XML to identify almost any conceivable data item because it gives them the ability to define document or page tags; HTML, on the other hand, uses predefined tags. That, in turn, allows Web pages to function like database records.

So how does SOAP fit into the picture? Simply put, it’s an enabling mechanism for XML exchange between applications. SOAP allows XML data to invoke objects running on remote servers across both corporate intranets and across the Internet. In practice, SOAP borrows heavily from the client/server model; it operates as a remote procedure call mechanism that leverages HTTP as a base transport, encoding requests and responses as XML documents. The first draft of SOAP provided support only for HTTP, but the revised version 1.2 specification supports SMTP and FTP as well.

SOAP’s support for a range of Internet protocols means it can easily traverse corporate firewalls, which obstructs any proposed application interoperability solution. Because SOAP object invocations can appear to a Web server as HTML code, for example, they can pass through existing firewalls without modification.

SOAP was originally created by Microsoft Corp., of all vendors, which submitted it as an open standard to the W3C in late 1999. SOAP enjoys the support of a host of industry heavyweights including IBM Corp., which helped prepare the revised version 1.1 of the specification that was placed before the WC3 last year. Other industry leaders that have announced support for SOAP are Hewlett-Packard Co., Ariba Inc., Compaq Computer Corp. and SAP AG.

That’s great, you say, but what does all of this mean? More importantly, how does it relate to mainframe environments?

SOAP is seen as an important cog in an XML platform integration stack that includes not only XML itself, but also a new business-to-business services standard called Universal Description, Discovery and Integration and another emerging standard called the Web Services Description Language.

SOAP support is expected to be incorporated in Web application server products from IBM and HP, among others. Also, Microsoft’s .NET application and services framework is expected to heavily leverage SOAP.

These technologies promise to link business partners, customers and possibly even competitors together over the Internet, says Mike Schiff, vice president of e-business and business intelligence with analyst firm Current Analysis. In this model, XML and SOAP work in tandem to enable companies to access the business-to-business services of other companies without regard for platform considerations. Meanwhile, Schiff says standards such as UDDI and WSDL provide core e-business description, location and registration services.