ISO 22666:2016 defines the AOS Space Data Link Protocol in terms of:
a) the services provided to the users of this protocol,
b) the protocol data units employed by the protocol, and
c) the procedures performed by the protocol.
It does not specify:
a) individual implementations or products,
b) the implementation of service interfaces within real systems,
c) the methods or technologies required to perform the procedures, or
d) the management activities required to configure and control the protocol.