(第5空)We initially described SOA without mentioning Web services, and vice versa. This is because they are orthogonal: service-orientation is an architectural  ( )  while Web services are an implementation  ( )  .The two can be used together, and they frequently are, but they are not mutually dependent.

For example, although it is widely considered to be a distributed-computing solution,SOA can be applied to advantage in a single system,where services might be individual processes with well-defined  ( )  that communicate using local channels,or in a self-contained cluster, where they might communicate across a high-speed interconnect.

Similarly, while Web services are  ( )  as the basis for a service-oriented environment, there is nothing in their definition that requires them to embody the SOA principles. While  ( )  is often held up as a key characteristic of Web services,there is no technical reason that they should be stateless-that would be a design choice of the developer,which may be dictated by the architectural style of the environment in which the service is intended to participate.