This Recommendation | International Standard specifies:

• procedures when operating over the connection-mode data link service for the connection-mode transfer of data and control information from one network entity to a peer network entity;
• the structure and encoding of the NPDUs used for the transfer of data and control information.

The procedures are defined in terms of:

• the interactions between peer network entities through the exchange of NPDUs;
• the interactions between a network entity and the network service user in the same system through the exchange of network service primitives;
• the interactions between a network entity and the data link service provider through the exchange of data link service primitives.

These procedures are applicable to instances of communication between systems which support the Network Layer of the OS1 Reference Model and wish to interconnect in the open systems environment using the Network Fast Byte Protocol.

This Recommendation | International Standard specifies, in clause 8, conformance requirements for systems implementing these procedures and provides the PICS proforma in compliance with the relevant requirements, and in accordance with the relevant guidance, given in ITU-T Rec. X.296 and ISO/IEC 9646-7. It does not contain tests which can be used to demonstrate this conformance.