SNA IMF/XL Node Manager's Guide (30293-90010)

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LU.T1: See Logical Unit
Type 1.
LU.T2: See Logical Unit
Type 2.
LU.T3: See Logical Unit
Type 3.
M
modem: An acronym for
MODulator-DEModulator. A
modem converts serial digital
data from a transmitting
terminal into a form suitable for
transmission over the analog
telephone channel. A second
modem reconverts this signal to
serial digital data for acceptance
by the receiving terminal. Bell
201, 208, and 209 modems are
used for synchronous data
transfer.
MPE: See MultiProgramming
Executive.
Multiple Virtual Storage
(MVS): An IBMoperating system
that is an extension of OS/MVT.
MVS is also known as OS/VS2
Release 2. IBM enhanced the
original version of MVS; these
enhanced systems include
MVS/SP (Multiple Virtual
Storage/System Product) and
MVS/XA (Multiple Virtual
Storage/eXtended Architecture).
MultiProgramming Executive
(MPE): The Hewlett-Packard
operating system for the HP 3000
computer. MPE consists of
programs that handle exchanges
between HP terminals, printers,
and executing programs and the
internal HP 3000
Communications Software.
MVS: See Multiple Virtual
Storage.
N
NAU: See Network
Addressable Unit.
NCP: See Network Control
Program.
network: A series of points
interconnected by a
communications channel. These
may be computers, terminals, or
other peripherals.
Network Addressable Unit
(NAU): Either a program or
group of programs that
represents the source and
destination of data in a network.
The three kinds of network
addressable units are SSCP, LU,
and PU. A communication session
must exist before data can be
transferred. Sessions are
established by the SSCP in this
order:
• First with the PU.
• Then, with each LU before two
LUs can communicate in a
session.
Four types of sessions exist:
• SSCP-SSCP
• SSCP-PU