Definition

A service operation specifies exchanges between participants.

A Service Interface is a template of a contract between entities (organizational, IT …). The contract is described by available operations which can be triggered trough messages exchanged by roles (vendor, buyer..).

Use in a Process Diagram

A conversation describes an exchange of several message flows between two roles.

A composite conversation is described by an service contract. This service interface contains service operations or sub-service interfaces.

Use in a Service Interface Diagram

A service operation use represents the usage of a service operation in an service interface.

A service interface use is associated to a service interface. It enables representation of complex exchanges.