Nor is any one major vendor's version emerging as a de facto standard in the public sector, since the government uses a wide range of vendors to encourage competition. "You don't just have IBM and BEA, you have Microsoft, SAP, Oracle, Accenture, Deloitte - all moving in different directions," says Kuhbock. Industry groups like the Integration Consortium are trying to facilitate consensus, and vendors are starting to agree to disagree, but this process is proceeding slowly, he adds.

Kuhbock emphasizes SOA is not a software tool or an IT project, but an architecture that enables communication between services, data and processes. "If you're constructing a building, you need concrete, beams and pylons, but if you don't have an architecture, you've created an unstable environment that can crash. Many IT systems were built as silos, so they're like buildings that don't have staircases or elevators to join the first and fifth floors."