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.