This Recommendation | International Standard defines in an abstract way the externally visible service provided by the OS1 Transport Layer in terms of
- the primitive actions and events of the service;
- the parameter data associated with each primitive action and event;
- the relationship between, and the valid sequences of, these actions and events.
The service defined in this Recommendation International Standard is that which is provided by all OS1 Transport Protocols (in conjunction with the Network Service) and which may be used by any OS1 Session Protocol.