Scope 1.1 This ITU-T Recommendation | International Standard defines (in an abstract way) the externally visible service provided by the OSI Presentation Layer in terms of a) the primitive actions and events at the user/service boundary; b) the parameter data associated with each primitive action and event; c) the relationship between, and the valid sequences of, those actions and events. 1.2 The service defined in this ITU-T Recommendation | International Standard is the connection-oriented service which is provided by the OSI connection-oriented presentation protocol and the the connectionless service which is provided by the OSI connectionless presentation protocol, each in conjunction with the OSI session-service. The connection-oriented presentation service defined in this ITU-T Recommendation | International Standard may be used by an OSI application protocol defined for connection-oriented transmission. The connectionless presentation service defined in this ITU-T Recommendation | International Standard may be used by an OSI application protocol defined for connectionless transmission. 1.3 This ITU-T Recommendation | International Standard does not specify individual implementations or products, nor does it constrain the implementation of entities and interfaces within a computer system. There is, therefore, no conformance to this ITU-T Recommendation | International Standard.