Enterprise developers can now test a set of Microsoft-hosted services that provide message routing, identity management, and (eventually) workflow services for applications that span multiple organizations. BizTalk Services are useful today only as a testing ground for components in the .NET Framework 3.0, and the WS-* protocols on which they are based. However, BizTalk Services could encourage use of Web services for business-to-business (B2B) commerce, extranets, and other kinds of cross-organization data sharing and collaboration. BizTalk Services are also an early example of a Microsoft platform service, a cornerstone of the company's recently announced "software plus services" strategy.

Experimental Phase

Despite the name, BizTalk Services have little to do with BizTalk Server, although BizTalk Server is Microsoft's B2B commerce product and will probably evolve to incorporate similar technologies.

Rather, these services can help developers explore how Microsoft's latest Web services platform, the .NET Framework 3.0, can be used in cross-organization composite applications—that is, applications built by connecting independent functions exposed as Web services. The .NET Framework 3.0 shipped with Windows Vista and includes the Windows Communications Foundation (WCF) messaging API, the CardSpace authentication system, and Windows Workflow Foundation (WF), among other components.

The first BizTalk Services became available as a free community technical preview (CTP), or pre-beta release designed to solicit customer feedback, in Apr. 2007. At launch, the following services were available:

BizTalk Connectivity Services. These services help developers expose a Web service securely from behind a firewall or network address translation (NAT) device. The first component of these Connectivity Services is a Relay Service, which supports a publish-and-subscribe model between applications on opposite sides of a firewall and allows multiple applications to subscribe to the same service. This allows Web services separated by firewalls to communicate, which is useful in B2B scenarios. For example, in a "just-in-time" manufacturing system, a supplier Web service could communicate with a manufacturer's Web service to check inventory levels, working through the Relay Service. Note that the Relay Service does not use WS-Eventing, a Web services protocol under development by the World Wide Web Consortium that also provides publish-and-subscribe functions over Web services. However, developers can use WS-Security and WS-ReliableMessaging for security and reliability.

BizTalk Identity Service. This service provides claim-based authentication for applications and Web-based services. Using Microsoft's CardSpace technology, Web services can present credentials to the Identity Service and request a security token, which can then be presented to other Web services as proof of identity. By acting as an authentication hub, the service can simplify identity management and authentication among business partners. For example, a supplier Web service could present a single set of credentials to authenticate itself to the Identity Service, obtain a security token, and then use that token to authenticate itself to multiple manufacturers, rather than authenticating itself multiple times, with separate credentials, for each manufacturer. Initially, the Identity Service will only support the WS-Trust protocol, which is implemented by Windows Server Active Directory Federation Services. However, Microsoft says it will eventually support Windows Live ID (the authentication system used by Microsoft's own Web sites and formerly known as Passport) and OpenID (a decentralized, community-developed authentication system used by some Web sites).

The BizTalk Relay and Identity Services are functionally similar to Groove Hosted Services, which Microsoft hosts to support its Groove collaboration product. The Groove client requires a relay service so that its document- and data-sharing traffic can cross firewalls, and an authentication service so that Groove users in different organizations can verify one another's identities and exchange encryption keys. However, the BizTalk services use WS-* protocols rather than Groove's proprietary ones.

Microsoft plans to roll out a third set of services, BizTalk Workflow Services, which will be based on the WF and will allow developers to graphically design workflows for composite applications. For example, a manufacturer could publish its purchasing process as a workflow, hosted at the service, which could then be used to coordinate transactions with all its suppliers.

The company emphasizes that BizTalk Services are in an experimental phase: they are not sufficiently reliable for production work and are far from feature-complete. In the long run, however, Microsoft plans to evolve them into what the company calls an "Internet Service Bus" (ISB), a set of platform services for composite applications that span multiple organizations. Although still in the visionary stage, this lends more clarity to Microsoft's stated goal of building platform services to stand alongside its traditional software platforms. However, while the company is focusing on the technological underpinnings, business issues such as licensing costs and service level agreements will be at least as important for success, and the company has not yet begun to discuss these issues.

Resources

The BizTalk Services SDK can be downloaded from labs.biztalk.net.

A white paper explaining the long-term goals and vision for BizTalk Services is at servicebus.biztalk.net/BizTalkServices.htm.

Microsoft's software plus services strategy is covered in "'Software Plus Services' Strategy Explained" on page 33 of the May 2007 Update.

BizTalk Server's likely incorporation of .NET Framework 3.0 technology is previewed in "Future BizTalk Could Change Workflow, Messaging".