Extensible and More
February 23, 2000
A Survey of XML Business Data Exchange Vocabularies
At the XML '99 conference last year, Steve McVey of Sterling Commerce remarked, "XML is very flexible. Everyone can do their own thing, and, by golly, everyone is!" A survey of current and planned applications of XML for exchanging business data suggests McVey knows the subject well! The good news is that the number of business vocabularies using XML is exploding. However, these applications have developed with few, if any, guiding standards for interoperability. Getting them all to talk to each other will be an enormous challenge for the Web standards community.
This survey, taken in January 2000, shows 124 different XML business vocabularies in use, development, or planning. Sources for the survey include leading directories of XML applications collected by XML.com, OASIS/Robin Cover, Schema.Net and IBM's alphaWorks. The survey also covers XML vocabularies registered with OASIS's XML.org and Microsoft's BizTalk.org portal, as well as those managed by Data Interchange Standards Association (my current employer) and other standards services.
The purpose of this survey is to show the extent of XML's penetration into the world of business data exchange, which covers transactions between businesses and also with consumers. As a result, the survey excludes XML vocabularies for enhancing XML, such as XML Schema, XPath, or XLink, even though they may have business implications. It also excludes applications designed for strictly publishing purposes, such as XHTML, even though they too may have use in business. But the survey tries to cover as many potential business data exchanges as possible, and thus includes scientific, technical, and even religious vocabularies.
To help understand the various ways in which XML for business data exchange has grown, the survey breaks down the applications into three major categories:
- Frameworks: specifications for structuring XML messages between parties for exchanges both within and among industries
- Functions: guidelines for specific business operations that cut across industry boundaries
- Verticals: messages for exchanges within a specific industry.
XML frameworks have probably received the most public attention, since they offer the most potential for interoperability. This survey found nine such specifications, in various stages of development. The list includes Microsoft's BizTalk and CommerceNet's eCo Framework, who have both announced their specifications, as well as ebXML, which is still in the planning stages. This group also includes collections of related document type definitions (DTDs) and schemas, such as those offered by the Open Applications Group and Commerce XML (cXML). The XML/EDI Group's guidelines are likewise included in this category, as well as the related XML/EDI workshop under the aegis of the European Standardization Bureau.
With any categorization scheme, some entries do not fit cleanly in the boxes -- RosettaNet is a good example. While RosettaNet is an undertaking of the computer technology industry, and therefore a candidate for the Verticals group, its approach of defining and modeling business processes, and then developing specifications, offers a framework for most industries to follow.
The Functions category includes 38 specifications, covering a range of common business operations. Many of these guidelines resemble EDI transaction sets or messages, such as purchase orders, order acknowledgments, and invoices. Others in the group perform message routing and management functions such as Information and Content Exchange, and the Directory Services Markup Language. Security and privacy functions, such as the W3C's Digital Signature and Platform for Privacy Preferences (P3P) fall into this category as well.
Among the close calls is Common Business Library (CBL), which provides a syntax and semantics for interoperability. While certainly beneficial to the development of XML business messages, CBL does not provide an overall message structure like BizTalk, eCo Framework, or that which ebXML has on the drawing board.
Another entry in this group that straddles the categories is the Extensible Financial Reporting Markup Language, which falls under financial services but covers common reporting functions required by most businesses.
Vertical market vocabularies -- serving a defined industry -- make up the largest number of entries in the survey, 77. This group best illustrates the challenge of interoperability facing the XML standards community. Firstly, some vocabularies cover only a single transaction, while others are collections of functions for industries, sometimes even within the same industry. For example, one of the BizTalk schemas is an Asset Financing Credit Application, while more general financial services languages also have this function.
Second, industry groups need to reconcile conflicting or overlapping specifications. The insurance business has ACORD and iLingo, for example. At least three separate specifications claim to serve the human resources community. Any hope for achieving interoperability needs to begin within these industry groups.
Some industry groups are beginning to resolve these differences. In the travel industry, the Open Travel Alliance (OTA), the group for which I serve as standards manager, decided to incorporate much of the Hotel Electronic Distribution Network Association specification in the first version of its standards. OTA is also negotiating with the Hospitality Industry Technology Integration Standards group to include its guidelines.
One of the close calls in categorizing the vertical market vocabularies is the Open Trading Protocol (OTP). While claiming to be "an interoperable framework for Internet commerce," OTP covers XML for Web retailing, rather than presenting a general approach for business. As a result it falls under vertical markets, although it cuts a wider swathe than most entries in this group.