A month ago, I wrote about the need for Service Oriented Architecture (SOA) to be based on standards if it is to fulfil its promise, and for a debate on what those standards should be. Since then, at The Open Group conference on SOA in Houston, Texas (presentations are available at http://opengroup.org/proceedings/q405/). I have seen signs of a very healthy debate. A picture of standards-based SOA is starting to emerge, based on lessons learnt from the first real-world implementation and deployment. What are the lessons learnt, and where will they lead SOA?

There is a clear pattern to initial SOA implementations. Existing applications are “wrapped” and plugged into a services bus. A registry may be added to enable service discovery, and there may be instrumentation for performance monitoring. This all works fine, because there has been no real change to the underlying enterprise architecture; it has just been expressed in SOA language.

The core business value of SOA is in delivering enterprise agility, and it is when companies try to change that the crunch comes. As Michael Liebow, global lead for SOA and Web Services within IBM Global Services, puts it, the business benefit of SOA is in service reconfiguration flexibility, with changes done in days by business people, not in weeks by technical specialists; but this means that the business and technical architectures must be aligned, which today is not the case in most organizations. Expressing an existing application architecture in SOA terms is not enough. The services must be business-oriented if they are to be orchestrated by business people.

Also, initial use of SOA is highlighting the need for semantic interoperability. David Archer, President and CEO of the Petrotechnical Open Standards Consortium (POSC), says that although SOA is providing the framework for integrated cross-company operations with information flow in real time required by current developments in the oil industry, there is a significant semantic interoperability problem that is not addressed directly by SOA. This has led to significant use of information repositories.

Most SOA implementers are still at the initial, wrapping, stage. Jamie Cruise, Solutions Architect with Landmark Graphics, says that he would love to be at the stage where legacy applications have been migrated. He looks forward to a time – hopefully within two years - when applications will talk web services natively, and will natively deliver industry–specific functionality.