And the early adopters are appearing. The large financial companies are involved in early SOA projects because they have the money and can see competitive advantage from SOA. One of the most ambitious projects is being built by the U.S government. Its aim is to replace all the accounting applications across the entire government with a single network-based, componentized solution that is integrated into the government's human resources operations as well. Whether this very ambitious project will succeed is open to question, but even if it does not, it will advance SOA development tremendously.

However, Reinecke says, the largest trends are almost inadvertent. Standardization and virtualization are driving SOA forward in many organizations even though they may not be using the term or have a clear vision of the goal.

"I am amazed at the speed with which people are moving away from client/server without even knowing it. They are consolidating data centers, and changing from client/server to XML- and Web-based applications," Reinecke says. This introduces a whole set of new protocols, with voice, data and video traffic sharing a single physical network layer. Reinecke defines four kinds of network traffic, each of which puts significantly different demands on network resources:

1. Non-real time traffic such as e-mail is the most tolerant of network interruptions and puts the least demand on network resources.

2. Near real-time traffic such as instant messaging needs a fast network connection but can tolerate some interruptions or congestion.