Furthermore, business systems may use different communication protocols to send messages, bringing compatibility problems. All-in-all, such problems have meant that, until very recently, only big business has taken a real interest in application integration.

What is really needed is a framework for developing standard industry message schemas. Servers like BizTalk server could then use these schemas as the basis for configuring their messaging system. Using this framework should mean that we can build a message format that complies to a relatively simple set of standard rules, but is also flexible enough to allow for collaboration during schema development. We also need to be able to implement this framework relatively inexpensively, which will allow small businesses to participate in application integration.

This was the motivation for the BizTalk Framework Initiative. The Framework was initiated by Microsoft, but it is explicitly designed to be open to everyone. It does not presuppose any specific operating system or software. It is a schema repository, and a set of messaging specifications, that can be implemented by some middleware server. Microsoft BizTalk Server is one such implementation, although it can also deal with messages outside the Framework. The schema repository has attracted dozens of partners and well over one hundred schemas. The initiative has three main thrusts:

• BizTalk Framework: a set of guidelines that enables reliable message exchange between organizations and applications
• BizTalk.org: a community web site that provides information about message exchange and its associated technologies, as well as a repository for message schemas
• BizTalk Server: software that processes BizTalk-compliant message documents

For the remainder of this chapter, we will take an introductory tour of the BizTalk Initiative, focusing especially on the Microsoft BizTalk Server 2000 software. But let's begin our tour with a look at the BizTalk Framework.

BizTalk Framework

The BizTalk Framework comprises rules for creating message schemas for document exchange. It is based upon two open standards:

• Extensible Markup Language (XML)
• Simple Object Access Protocol (SOAP)

Let's have a closer look at these standards, because it will help us to understand the structure of the BizTalk Framework.

XML

Although the "M" in "XML" is short for "Markup", XML is not just a markup language as you may think. Confused? Let me explain.

A markup language is one that allows us to mark up data; in other words the language allows us to add meta data that describes the data. An example is HTML, the universal language for the display of information, where we place data between simple tags, which label the data in some way.

XML is different; it is not really a "language" at all, but a standard syntax that allows us to create markup languages. It enables you to create a clear, human-legible, custom markup language that is well suited to your needs. Therefore, an XML-based framework for messages is ideal, since it is flexible yet descriptive and clear.

SOAP

We have already mentioned the problems associated with exchanging messages between systems with different protocols. A message may invoke a method on an object on one system or platform, but it will probably have trouble doing so on a system that uses a different communication protocol.

To work around these platform-specific data-accessing problems, the Simple Object Access Protocol was proposed. SOAP is an XML-based syntax that defines an electronic envelope into which you put data. It enables us to produce applications that can remotely invoke methods. A SOAP package consists of a SOAP client and server, which are used in the following way:

1. The SOAP client creates and submits a SOAP request document (over HTTP) to a SOAP server at another site.

2. The SOAP server grabs the message, parses the SOAP document, and invokes a method on a remote object on its domain.

3. The remote object returns information to the server, which places it in a SOAP document and sends it on to the SOAP client.

Therefore a SOAP server acts as an interpreter, and the SOAP package itself provides an interface between two incompatible protocols.

BizTalk Messages

So, where does the BizTalk Framework fit in? Well, a BizTalk document is an extension of a SOAP document, incorporating extra BizTalk-specific XML tags (BizTags). A server that implements BizTalk Framework is expected to recognize and act on the BizTags in the manner prescribed by the Framework. The BizTalk Framework is also largely based upon the SOAP standard, and so BizTalk messages have the advantages we have just discussed of both XML and SOAP: extensibility, clarity, and platform-independence.

Of course, developers at many companies will have to independently adopt the framework's conventions if it is to be generally useful as a messaging protocol for ad hoc and open electronic commerce. The message schemas themselves could be used outside of the BizTalk Framework, but the processing implied by the BizTags requires implementation of the messaging laid out in the Framework. Even assuming developers do embrace the framework as a useful approach, the success of B2B efforts using BizTalk is not assured. The first three types of business integration - business process integration, trading partner integration, and automated procurement - can occur between small numbers of participants. This has been the history of EDI to date. A few participants willing to commit to a long process can manually establish agreements on technology and data interchange formats. The result is a large potential benefit to the participants, but no guarantee that the benefits will spread to the business community at large.

Business to business aggregation is required to promote B2B electronic commerce for the multitude of small and medium-sized businesses. Such businesses cannot afford proprietary networks and lengthy development efforts. They seek widely adopted frameworks running on commodity systems that make use of open protocols. This is what the BizTalk Initiative will provide.

BizTalk.org

To promote the use of BizTalk Framework documents and XML-based messaging in general, the BizTalk.org web site (www.biztalk.org) was created. This site, which is hosted and managed by Microsoft, provides information on the BizTalk Framework, BizTalk community news and forums, and tools to help with application integration.

The site also contains a repository of XML schemas representing message formats designed by companies embarking on implementing the BizTalk Framework. There are, for example, schemas for ordering food services or building maintenance services. The repository provides open access for anyone who wishes to publish a new message schema, or find useful schemas already published. It also serves to educate developers by providing examples of well-designed interchange formats. A developer can be assured that any schema published in the repository has been tested and is technically valid.

Long-term, however, the repository could be the cornerstone in a B2B aggregator portal; potential partners could obtain the schemas of vendors and initiate integration efforts. As BizTalk Server comes into wider use within the corporate world, BizTalk Framework can leverage the community formed around the educational mission, to create a B2B aggregator portal compatible with BizTalk Server. Although the framework does not require the use of BizTalk Server, so any third party can develop to the its conventions, developers who have learned to use BizTalk Server effectively will have a distinct advantage over newcomers to the Framework.

BizTalk Schema Repository

If application integration between trading partners relied on formal coordination, business-to-business integration would be slow to take off. To be successful, a prospective partner must first locate a suitable partner and then find out what sort of schemas they use. Next, the partner must either adopt those schemas or specify a mapping between their own schemas and the new partners. As we shall shortly see, BizTalk Server provides tools for the final step. A central repository of e-commerce schemas is needed to address the first two steps.

The BizTalk.org web site hosts just such a library. Prospective trading partners can go to the site and search by schema keywords or industry categories. The latter are defined in terms of the North American Industry Classification System (NAICS), a system of classification codes that progressively refine a business in terms of the industry groups or categories to which it belongs. By using a combination of the two, a prospective customer of the published partner can identify a small number of schemas and inspect them to see if they are relevant to its needs.

Upon finding relevant schemas, a trading partner can download and inspect detailed information. Each schema listed on the site has three documents: the schema itself, HTML-based programming documentation, and a sample message that complies with the schema. The sample is especially important as it communicates a sample of what the schema developer meant when they devised the schema. This helps a prospective trading partner decide if the schema is relevant, and if so, helps its programmers understand the schema.

Developers can rapidly perform integration with little intervention from a prospective partner by writing software that speaks to the partner's published schemas. If the developers are building an electronic commerce capability from scratch, they can adopt the vendor's published message formats as their own, writing internal software to the published schemas. If, however, they have an existing capability, they will need to design mappings between their own formats and those of the prospective partner. This is a task supported by the tools in BizTalk Server. Intervention by the prospective trading partner is required only when the two companies negotiate a workflow agreement.

The repository helps in another way. Schemas may be expected to evolve over time. Users of schemas should not have to rely on the schema originator for update notifications; after all, the whole point of a central repository is to get away from one-to-one coordination. When a trading partner finds a relevant schema, it can register its interest in the schema with BizTalk.org. When a new version of the schema is uploaded to the repository, the partner receives an e-mail notification. In addition, schema interest registrations are used to provide feedback to the original designer and to rank schema searches in order of their popularity. This ranking will reflect the rate of adoption of a particular schema, helping the trading community to coalesce around emerging standards.

Other Message Schema Repositories

BizTalk.org is not the only e-commerce message schema repository. A number of organizations are joining the repository effort. Although most focus on XML as the basis for exchanging business information, some use other techniques as well. It is far too early to predict how the market for repositories will evolve: it may organize itself around the portals of vertical market communities, or it may coalesce around the software used to implement e-commerce. There may be a few dominant repositories, or so many that every new trading relationship involves the exploration of a new repository. It is worth taking note of the pioneer repository efforts so that we can see where BizTalk's competition lies, and how other organizations view business-to-business data interchange.

OASIS

The Organization for the Advancement of Structured Information Standards (OASIS) is a non-profit organization that hosts www.xml.org. This site seeks to become a reference repository for industrial and commercial vocabularies expressed in XML. As of this writing (December 2000), OASIS is beginning to host XML message schemas and DTDs for e-commerce. A committee is in the process of defining the process by which a searchable repository will operate.

OASIS is also participating in an international effort, the Electronic Business XML Initiative, along with the United Nations Body for Trade Facilitation and Electronic Business (UN/CEFACT). The initiative seeks to develop a consistent framework for developing XML vocabularies for e-commerce.

The repository may be found at www.xml.org, while OASIS itself resides at www.oasis-open.org

RosettaNet

This is another repository effort that takes a layered approach to developing e-commerce vocabularies. RosettaNet is an industry consortium of diverse businesses seeking to develop a common e-commerce framework. RosettaNet sees three layers supporting commerce:

• dictionaries
• frameworks
• Partner Interface Processes (PIP)

A dictionary, in their view, is a collection of words or properties that can be used to describe business transactions. RosettaNet is engaged in writing two data dictionaries. The first is intended to describe product properties. The other will provide properties describing catalogs, partners, and transactions. Next, these words and properties will be combined through interchange protocols to form a grammar.

RosettaNet's framework will consist of XML DTDs that describe e-commerce protocols.

The real focus of RosettaNet, however, is their PIP concept. They see a PIP as a dialog between two business partners. A PIP consists of some collection of XML interchange documents and a business model that describes how trading partners interact. A PIP also provides a mechanism for validating individual documents.

RosettaNet imposes more structure on would-be partners than BizTalk does. Where BizTalk provides a loose framework for message vocabularies, and some placeholders for information of interest to consuming applications, PIPs impose a protocol for the exchange of messages. This is useful if you desire a complete and tested protocol for your integration. Unfortunately, it also limits the reach of the project by excluding any integration projects for which a PIP has not been specified. It is consequently more focused on particular markets and business flows than BizTalk.

RosettaNet is found at www.rosettanet.org

CommerceNet

Like RosettaNet, CommerceNet is a consortium. It casts a wide net, involving over 500 businesses and organizations and embracing a variety of e-commerce protocols. CommerceNet was founded in 1994, so it is somewhat more developed than the other efforts. Its principal focus is on bringing together partners to engage in particular opportunities.

CommerceNet's most significant effort from the standpoint of this book is the eCo Framework. This framework seeks to provide a common structure for all e-commerce specifications, including EDI, Open Buying on the Internet (OBI), and a variety of XML-based vertical market vocabularies.

CommerceNet's site is found at www.commerce.net

BizTalk Servers

In order to be able to use the BizTalk Framework to integrate applications, we need software that can process the message documents and do something useful with them. The BizTalk Framework can be implemented by any software, as long as it conforms to the guidelines laid out in the Framework. In fact, several companies are working on servers that will process BizTalk documents. One of the most-heralded products is Microsoft's BizTalk Server 2000, which we will now investigate.