Driving the Enterprise Service Bus

Sonic augments its use of Web services with asynchronous messaging in its enterprise service-bus architecture, with each service definition kept in a common directory. A global communications management infrastructure also is used.

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Path to seamless integration

Yet even the gung-ho ESB executives at Sonic concede these are early days.

"The technology is still pretty new and we're still working on solidifying the first couple generations of products that are using enabling protocols," said Gordon Van Huizen, vice president of product management at Sonic Software in Bedford, Mass.

IBM's Holbrook adds that standards in areas such as reliable messaging still need to evolve for Web services-based architectures to catch on in greater volumes.

David Clarke, executive vice president of product strategy at Cape Clear, based in San Mateo, Calif., gives the issue some perspective.

"ESB is an attempt by the industry and the analysts to try to tie down the key things you need in a Web-services platform," Clarke said. For enterprises such as Pacific Life, an insurance company in Newport Beach, Calif., that clarity is essential.

The company's experience illustrates the core opportunity for the ESB in the future. Pacific Life plans to implement a Web services-based ESB to eliminate complicated mainframe programming required to make policy information more accessible to users.

Pacific Life plans to use Cape Clear's CapeConnect product plus Inner Access technology, which will expose CICS Cobol transactions as Web services, says Cort Klein, system architect at Pacific Life.

The company hopes its new Web services-based methodology will improve the current system in which Pacific Life must link to mainframe data via TCP/IP before undertaking labor-intensive processes.

These processes include inputting parameters into a Cobol copy book and serializing the marshalling and translation back and forth, Klein says.

"With Web services, all that code is generated automatically. We've done proofs of concept where it works quite nicely," Klein explains.

This seamless integration of data highlights what Gartner's Thompson says will be another driver of ESB technology development: composite applications.

In composite applications, the user sees a single application but behind the scenes the application actually is made up of components of individual, stand-alone applications.

"It costs less than one-tenth what the integrator broker does," about $8,000 to $10,000 as opposed to a $125,000 broker, Thompson explains.

As such, ESB presents "a better iteration of how to implement a service-oriented architecture," says Cape Clear's Clarke. "It turns out that Web services is a very good way to define these services, these contracts, in a way that is very implementation-neutral because most historical attempts to define this service-oriented architecture have been very tightly coupled with a particular implementation approach," such as CORBA or DCE [Distributed Computing Environment]."

ESBs, IDC's Hailstone adds, require at least a standards-based message capability. Message routing is needed for transforming message content and some level of security may be needed for filtering, he says.

Looking down the road, the other component of this discussion under close scrutiny will be the use of Java in SOAs.

Java Messaging Service has been prominent in ESBs, Hailstone said. "[JMS is important] to the extent that I've not seen any product that claims to call itself an ESB that doesn't use Java messaging," he says.

An application server is not a good option for running an ESB since it may be too clumsy for the task at hand, Hailstone claims.

Application-server heavyweight BEA Systems not surprisingly argues otherwise. "The application server has a central role in [an ESB]," said Byron Sebastian, vice president and general manager of WebLogic Workshop and WebLogic Portal at BEA in San Jose, Calif. "It provides core components of the Web services standards and it provides the JMS."

Yet, regardless of application-server debate, analysts expect big things from the technology. IDC analyst Sally Hudson wrote in a March 2003 report that ESB "will revolutionize IT and enable flexible and scalable distributed computing for generations to come."

When it comes to the development of loosely coupled enterprise applications, Sebastian offers a more realistic perspective of ESB's role. "Most people are using a Web services interface either alone or in combination with a service bus," he said.