Middleware, Muddleware: Sorting ESBs from WWFs from BizTalk from Indigo
Posted 11:45 AM    

I used to think I understood middleware.

Six years ago it was fairly simple in concept if not in execution. There were transaction servers, message queuing, synchronous and asynchronous. If you were an IBM shop you used MQSeries and later Microsoft had its equivalent.

But as distributed applications built on frameworks have gotten more complex, so have the options and the terminology. In particular, the emergence of Enterprise Service Buses (ESBs) has gotten extensive attention, yet the term ESB seems to have as many definitions as vendors, making it as nebulous as SOA.

Then Microsoft entered with its unique approach to the stack, which begs the question: Is Indigo an ESB, or is BizTalk, or Windows Workflow Foundation? Borrowing some quotes from a Microsoft white paper shows the diversity:

"A Web-services-capable infrastructure that supports intelligently directed communication and mediated relationships among loosely coupled and decoupled biz components."                                                   –Gartner Group

"The ESB label simply implies that a product is some type of integration middleware product that supports both MOM and Web services protocols."

                                                                        –Burton Group

"A standards-based integration backbone, combining messaging, Web services, transformation, and intelligent routing."                    –Sonic Software

"An enterprise platform that implements standardized interfaces for communication, connectivity, transformation, and security."                     –Fiorano Software

"To put it bluntly: If you have WebSphere MQ and other WebSphere brokers and integration servers, you have an ESB."                        –Bob Sutor, IBM

"The Enterprise Service Bus is a uniform service integration architecture of infrastructure services that provides consistent support to business services across a defined ecosystem. The ESB is implemented as a service oriented architecture using Web Service interfaces."                                          –CBDI

On the Microsoft front, we now have Windows Workflow Foundation added to BizTalk Server 2006 (promised for the first quarter), and Windows Communication Foundation, formerly known much-more-memorably as Indigo. After wading through a host of information on MSDN, I found this delightfully concise description on Scott Woodward's blog:

            Put simply:

                        A. Workflow within applications = Windows Workflow Foundation

                        B. Workflow across applications = BizTalk Server

And later this description of Indigo per Microsoft. "Windows Communication Foundation (WCF) is Microsoft's next generation Web services technology that provides a highly productive framework for building secure, reliable and interoperable software based on industry standards. WCF extends the .NET Framework 2.0 with additional functionality." And: "WCF provides the broadest support for the WS-* specifications—maximizing customers' ability to interoperate with a broad range of systems in a heterogeneous environment. In its first release, WCF will support the following WS-* specifications: SOAP, WSDL, WS-Addressing, MTOM, WS-Policy, WS-Security, WS-Trust, WS-SecureConversation, WS-ReliableMessaging, WS-AtomicTransaction, and WS-Coordination as well as the foundational specifications of XML, XSD, and XPath."

Here are some resources to help sort out the different positions and products. We're planning a suite of articles to explore this in more depth, so suggestions on what we should cover are appreciated.

Ø      Message bus patterns and practices on MSDN.

Ø      Our suite of Indigo reports and video.

Ø      Our Special Report on ESBs.

Ø      Microsoft also has a white paper "Microsoft on the Enterprise Service Bus (ESB)" at this link.

Ø      One of the pioneers of the ESB is Sonic. At our Enterprise Architect Summit Barcelona earlier this month, speaker David Chappell apparently got into a bit of a debate with Microsoft attendees in the audience. David describes his view of the discussion here, and you can listen to the original and watch its slides here.

Ø      An interesting perspective can be found at MS product manager Scott Woodgate's blog.

Ø      Search results on MSN (Google did poorly on this one).

In "the glass is half full" mentality, look at this complexity as guaranteed employment for those of us who haven't had our jobs offshored.