I have a confusion regarding whether an interface for an agent class of some agent module should be included in domain layer? by agent I mean a class / module that interacts with external wcf/ webservices.
I have a diagram that shows it. In short, is it Ok to have:
IProductAgent interface in Business layer where the actual implementation will be in an Agent Module.
The confusion arises by the fact that: Is calling a service even considered a business rule?
Today a service fulfills a facility, tomorrow there might be some another means of catering this same facility. Liskov's Substitution Principle.
Apologies if I am mixing things here.