Component software eases Web services

A common component architecture (CCA) for grid-based applications in conjunction with a grid-based "application factory" could...

A common component architecture (CCA) for grid-based applications in conjunction with a grid-based "application factory" could simplify Web services in a grid environment, according to Dennis Gannon, a researcher with the pervasive technology lab at Indiana University.

Speaking at the Global Grid Forum, Gannon said his team is looking at the needs of application users who want access to a computing grid and the applications hosted on it, but "do not want to have to deal with the intricacies of grid programming."

"The idea is to compose software as components [with a] port, which is an interface. And you access that interface by evoking the methods of this port. The CCA extends this idea a little bit in that a component also has a different type of port which [identifies and connects] to the provider of that service," Gannon said.

These CCA ports would operate within the framework of what Gannon called an application factory that would reside as an additional tier just behind a service provider's Web server front end. Requests to the grid for any specific type of computing would hit the application factory, which would then identify, locate, and authorise the use of the types of applications that need to come into play in the grid to complete the computation, Gannon explained.

The result would be an interface based on a grid's Web services layer, "a Web-based portal which can be used to launch, configure, and control distributed grid applications," he said.

Known protocols such as SOAP would be "the default protocol" for CCAs. A free, XML and SOAP-friendly programming language called Python script could be used to connect individual CCAs, Gannon said.

CCAs could also be used to encapsulate legacy applications within a grid environment that were developed prior to the idea of CCAs, making them work seamlessly and transparently within the grid, Gannon said.

While delivering applications potentially owned by separate entities to a single user request could be streamlined by CCAs, how such Web services would be billed is still something of an unanswered question.

Dr. Robert Cohen, director of Cohen Communications Group said of Web service billing in a grid environment: "The economic models are still fairly undefined. The problem is you are not dependent on a single point or vendor." He added: "If the network provider becomes the sell-through, they may be able to bill more than the application provider."

Wielding greater influence at first, "the established vendors - such as Microsoft - will be able to bill more for intellectual property" in a grid environment where resources are collected from multiple vendors," Cohen said.

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