DATA PROCESSING, OPEN SYSTEMS INTERCONNECTION, DATA LINK LAYER (OSI), DATA TRANSMISSION CONTROL PROCEDURES, HIGH-LEVEL DATA LINK CONTROL, COMPATIBILITY
被代替标准
ISO 7809
适用范围
This National Standard of Canada is equivalent to International Standard ISo
7809-1984. 1 Scope and field of application This International Standard describes the HDLC unbalanced classes of procedures
and the HDLC balanced class of procedures for synchronous data transmission. Balanced operation is intended for use in circumstances which require equal
control at either end of the data link. Operational requirements are covered
in accordance with the overall HDLC architecture. The procedures use the HDLc
frame structure defined in ISO 3309 1) and the HDLC elements of procedures
described in ISO 4335 2). For the unbalanced classes, the data link consists of a primary station plus
one or more secondary stations and operates in either the normal response mode
of the asynchronous response mode in a point-to-point or multipoint
configuration. For the balanced class, the data link consists of two combined
stations and operates in the asynchronous balanced mode in a point-to-point
configuration. In each class, a basic repertoire of commands and responses is
defined, but the capability of the data link may be modified by the use of
optional functions. 1) ISO 3309, Data communication - High-level data link control procedures -
Frame structure. 2) ISO 4335, Data communication - High-level data link control procedures -
Consolidation of elements of procedures.