CAN/CSA-Z243.145-87

This National Standard of Canada is equivalent to International Standard ISo 8073-1986. 1. Scope and field of application This International Standard specifies a) five classes of procedures: 1) class 0: simple class; 2) class 1: basic error recovery class; 3) class 2: multiplexing class; 4) class 3: error recovery and multiplexing class; 5) class 4: error detection and recovery class; for the connection oriented transfer of data and control information from one transport entity to a peer transport entity; b) the means of negotiating the class of procedures to be used by the transport entities; c) the structure and encoding of the transport protocol data units used for the transfer of data and control information. The procedures are defined in terms of a) the interactions between peer transport entities through the exchange of transport protocol data units; b) the interactions between a transport entity and the transport service user in the same system through the exchange of transport service primitives; c) the interactions between a transport entity and the network service provider through the exchange of network service primitives. These procedures are defined in the main text of this International Standard supplemented by state tables in annex A. These procedures are applicable to instances of communication between systems which support the Transport layer of the OSI Reference Model and which wish to interconnect in an open systems environment. This International Standard also specifies conformance requirements for systems implementating these procedures. It does not contain tests which can be used to demonstrate this conformance.