A WSDL document describes a service:
- message(s) accepted and emitted: abstract description (XML Schema)
- network protocol(s) and message format(s)
- operation: exchange of messages
- port type: collection of operations
- port: implementation of a port type
- service: collection of ports
N.B. operations are atomic response+request
pairs, not transition networks or state machines.
Rules of operation are not captured completely.
Controversy over general vs specific interfaces.
