A new service model

Here is a revised diagram for the service model.

Some comments:

1. The policy aspects are included:
    a. A policy is established by the service owner
    b. A service is associated with a role within the person/org owning 
the service
2. There is some redundancy now because a service is a resource, that 
has identifiers, owners and policies etc. However, in this case, there 
are some extra links that might help to explain how policies etc. fit 
with services.
3. The task/goal/action has been adjusted to task/action/state. 
Essentially its the same, but calling it an achievable state is perhaps 
less contentious and easier to understand. (State and goals are duals 
of each other.)
4. The relationship with messages is explicated better. Interfaces are, 
in fact definitions of the messages; with an implied semantics of those 
messages. Actions performed as a result of receiving a message are 
consequences of the semantics of the service.
5. A service has one or more roles. This has two further links: the 
role within the organization and the role in relation to the messages 
processed/emitted by the service.
6. Choreography is removed from the diagram; it could be re-instated.
7. I think that this picture gives a better explication of the 
fundamental relationship between services, providers, owners and 
messages. It also explains intermediaries; both of the SOAPy kind and 
of the more general kind (although intermediaries themselves are not in 
the diagram - they are a special kind of service.)

Some issues:
1. Whether to maintain the redundancy wrt policies
2. Whether to put choreography back in.
3. Whether to call out the service role explicitly.

Again, as before, in the absence of significant pushback, I will revise 
the concepts and relations text to accommodate this view. I don't 
propose to remove choreography from the text of the C&R section though.

Frank