CAN/CSA-ISO/IEC-8473-1-95

The international community has decided to make this standard available only in the English language version. It has been adopted as a National Standard of Canada on this basis. This National Standard of Canada is equivalent to International Standard ISO/IEC 8473-1:1994. 1 Scope This Recommendation | International Standard specifies a protocol that is used to provide the connectionless-mode Network service described in CCITT Rec. X.213 | ISO/IEC 8348 and to perform certain Network layer management functions. The protocol relies upon the provision of an underlying connectionless-mode service by real subnetworks and/or data links. The underlying connectionless-mode service assumed by the protocol may be obtained either directly, from a connectionless-mode real subnetwork, or indirectly, through the operation of an appropriate Subnetwork Dependent Convergence Function (SNDCF) or Protocol (SNDCP) over a connection-mode real subnetwork, as described in ISO/IEC 8648. This Recommendation | International Standard specifies the operation of the protocol with respect to a uniform, abstract "underlying subnetwork service". Other Recommendations | International Standards specify the way in which this "underlying subnetwork service" is obtained from real subnetworks, such as those which conform to ISO/IEC 8802 or ISO/IEC 8208. The "underlying subnetwork service" may be obtained from real subnetworks other than those that are specifically covered by the other Recommendations | International Standards. This Recommendation | International Standard specifies a) procedures for the connectionless transmission of data and control information from one network-entity to one or more peer network-entities; b) the encoding of the protocol data units (PDUs) used for the transmission of data and control information, comprising a variable- length protocol header format; c) procedures for the correct interpretation of protocol control information; and d) the functional requirements for implementations claiming conformance to this Recommendation | International Standard. The procedures are defined in terms of a) the interactions among peer Network entities through the exchange of protocol data units; b) the interactions between a Network entity and a Network service user through the exchange of Network service primitives: and c) the interactions between a Network entity and an abstract underlying service provider through the exchange of service primitives. This Recommendation | International Standard also provides the PICS proforma for this protocol, in compliance with the relevant requirements, and in accordance with the relevant guidance, given in CCITT Rec. X.290 | ISO/IEc 9646-1.