This Recommendation provides the architecture of the IN CS-2 service plane. The service plane is the "top" plane in the IN conceptual model which is defined in Recommendation Q.1201 "Principles of Intelligent Network architecture". This Recommendation provides the first view of the "top-down" approach where the services and service features are defined first and then the network capabilities to support/provide these capabilities are developed and realized on the lower planes (global functional plane, distributed functional plane and physical plane, respectively) of the IN conceptual model. This Recommendation further discusses the subjects of feature interactions, cooperations and interferences which were not addressed in the first issue of IN, i.e. IN CS-1. This Recommendation represents the user’s view of services supported by an IN.