NBN ISO 21218:2021

This document specifies general technical details related to the access layer of the ITS station reference
architecture specified in ISO 21217 including:
— the service access point (SAP) of a communication interface (CI) as provided by the communication
adaptation layer (CAL) for communication, named IN-SAP, and related service primitives and service
primitive functions;
— the SAP provided by the CI management adaptation entity (MAE) for management of the
communication interface, named MI-SAP, and related service primitives by reference to ISO 24102-3,
and service primitive functions.