Web services is a glamorous term for a very old and established idea. The
core Web services technologies, SOAP and WSDL, allow developers to define new
protocols. A protocol is nothing more than a way for computer programs to
talk to each other over computer networks. As long as there have been
networks there have been protocols. What makes Web services unique is that
they're the first mainstream technologies, supported by all major vendors,
intended to make the creation of new protocols so easy that ordinary business
developers can do it.
Developers who, for instance, build a SOAP wrapper around their payroll
systems may not think that they're building their own protocol, but in fact
they are. Web service developers must decide how to group their logical
objects into services. They must create some technique to correlate messages
sent to the service with particula... (more)