Scope This Recommendation | International Standard defines the OSI Network Service in terms of: a) the primitive actions and events of the Service; b) the parameters associated with each primitive action and event, and the form which they take; c) the interrelationship between, and the valid sequences of, these actions and events. The principal objectives of this Recommendation | International Standard are: 1) To specify the characteristics of a conceptual Network Service and thus, supplement the Reference Model in guiding the development of Network Layer protocols. 2) To encourage convergence of the capabilities offered by providers of sub networks. 3) To provide a basis for the individual enhancement of existing heterogeneous sub networks to a common sub network-independent Network Service to enable them to be concatenated for the purpose of providing global communication. (Such concatenation may involve optional additional functions which are not defined in this Recommendation | International Standard.) A definition of the quality of service is an important element of this Recommendation | International Standard. 4) To provide a basis for the development and implementation of subnetwork-independent Transport Layer protocols decoupled from the variability of underlying public and private subnetworks and their specific interface requirements. This Recommendation | International Standard does not specify individual implementations or products nor does it constrain the implementation of entities and interfaces within a system. There is no conformance of equipment to this Recommendation | International Standard. Instead, conformance is achieved through implementation of conforming OSI Network protocols which fulfill the Network Service defined in this Recommendation | International Standard.