Practical Web Services slide-3

What's A Web Service?

No technology designations without a technical difference.
Web services are not just RPCs with SOAP.

A web service is
a service with a contract:
a set of local "laws" or at least promises.

A web service is

a possibly remote procedure with an

invocation that is described in a standard (preferably XML-based) machine readable syntax

reachable via standard Internet protocols

with a description, including at a minimum the allowed input and output messages, as well as

a possible semantic annotation of the service function and data meaning.