Systems 'Logical Units
This book describes Systems Network Architecture (SNA) as
it relates to sessions between logical units (LUs). LUs are the
ports through which application programs, terminals, and
terminal operators communicate across an SNA network.
LU to LV sessions support communication between these
This book describes the structure of an LU and defines the
characteristics of five types of LU to LU sessions (types 1
through 4, and type 6). It also describes the data streams that
are valid for each type of LU to LU session.
This book does not describe any specific equipment or pro-
grams that may implement SNA, nor does it describe any
implementation subsets or deviations from the architecture.
These matters, as well as informat|