MAC (Media Access Control) layer A
sub-layer of the Data Link Layer (Level Two) of the ISO OSI Model
responsible for media control.
MAN (Metropolitan Area Network) A
high speed network designed to link together sites in a metropolitan
or campus area. The IEEE has defined its 802.6 standard for MANs
based on the Distributed Queue Dual Bus technology.
MAP (Manufacturing Automation Protocol) An
ISO OSI protocol stack that is defined as a functional profile.
Originally developed by General Motors for use in factory floor
manufacturing environments it is based around the IEEE 802.4 Token
Bus LAN technology.
MAPI (Messaging Application Programming Interface)
Microsoft's standard for the applications
interface to e-mail. See also VIM.
Master station A device
that controls/polls the nodes in multipoint circuits or, in point-to-point
circuits, the unit that controls the slave station. In LAN terms,
the device on a token passing ring that enables recovery from
error conditions, such as lost, busy or duplicate tokens, usually
by generating a new token. Servers are sometimes called master
stations.
Matrix switching A
form of data switching at the heart of ATM, enabling the appropriate
of bandwidth to be available end-to-end for the duration of the
session without contention.
MAU (Medium Attachment Unit) A
transceiver (transmitter/receiver) comprising hardware circuitry
that provides the correct electrical or optical connection between
the computer and IEEE 802.3 LAN media. Since MAUs typically support
only one type of network medium, a choice of MAUs is available
to support different media. It detects carrier and collision activity,
passing the information to the Computer. It can be a standalone
unit or incorporated in a circuit board inside the computer,
Media Access Control driver A
LAN device driver that works directly with the network adapter
cards, acting as an intermediary between the transport driver
and the hardware.
Medium The physical
method or equipment used for transmission, from a tangible fiber
optic or copper cable to a satellite link. Alternatively, a little
old lady in a shawl used as a last resort to retrieve lost data.
Medium Interface Controller (MIC) An
hermaphrodite connector on IBM patch parels specified in 802.5.
Member server A server
in a domain that keeps and uses a copy of the domain's user accounts
database but does rot validate logon requests.
Monolithic driver A
network device driver that acts as network adapter card driver
and transport protocol driver combined.
MMS (Message Handling System) The
engine underlying an electronic messaging system. Also a proprietary
e-mail integration scheme developed by Action Technologies.
MIB (Management Information Base) The
set of variables or database that a gateway running CMOT, SNMP,
or CMIP network management protocols maintains. It defines variables
needed by the SNMP protocol to monitor and control components
in a network. Managers fetch or store into these variables. MIB-II
refers to an extended SNMP management database that contains variables
not shared by both CMOT and SNMP. The CMIP and SNMP MIB formats
differ in structure and complexity.
Microchannel A proprietary
bus developed by IBM for its PS/2 computer family's internal expansion
cards. It offers improved performance over ISA-based machines
like the IBM PC/AT.
Microwave Wireless
transmission at very high frequency to deliver telecommunications
services, including TV distribution, between two points. It is
dependent on line of sight.
MTBF (Mean Time Between Failures) A
term describing the reliability of equipment established by testing
kit to its limits and promoting the MTBF as a selling point. As
most users know, however, laboratory and operational environments
have little in common.
MNP (Microcom Networking Protocol) A
series of protocols designed by Microcom to support error control
and data compression for asynchronous modem transmission.
Milnet (Military Network) Originally
part of Arpanet, Milnet was partitioned in 1984 to make it possible
for military installations to have a reliable network service
while the Arpanet continued to be used for research. Under normal
circumstances, Milnet is part of the Internet.
Modem A device named
from an amalgam of the words modulator and demodulator. A modem
will modulate an outgoing binary bit stream or to an analog carrier,
and demodulate an incoming binary bit stream from an analog carrier.
Modem Approvals Group Established
in January 1993 to raise awareness of the UK law against connecting
unapproved devices to the PSTN, this group demands a level playing
field in the modem market with better law enforcement or more
open standards.
Modem eliminator A
device that can replace a modem in some instances when the distance
to be covered is short. It takes the power it needs to operate
from the transmission line.
MSAU (Multi-Station Access Unit) A
wiring concentrator on a Token Ring network that allows devices,
typically eight to 12 Token Ring stations, to be connected to
the ring. Relays in the MAU ensure the integrity of the network
when devices are attached or removed. A Managed Multi-Port/Multi-Station
Access Unit has built-in network management support.
MS-Net Microsoft DOS-based
networking system software product (Microsoft Network).
Multi-drop A transmission
circuit with multiple terminals and peripherals. Could also be
described as branches off a bus.
Multi-point A link
that connects more than two points. Interchangeable with multi-drop.
Multi-point connection A
single channel or circuit interconnecting devices in different
locations. This usually means using polling techniques with each
terminal[terminal a unique address. Also know as a multi-drop
line.
Multi-cast bit A bit
found in the Ethernet addressing scheme that indicates that the
message is to be sent to all stations.
Multi-cast message A
message that is intended for a set of stations on a network.
Multimedia Generic
description of the generation and transfer of voice/data/video
traffic between users. Applications to exploit multimedia to the
full are emerging in the wake of advanced switching techniques
and develop merits in desktop and server processing architectures.
It may be essential to a physically separated group that communicates
as if it was physically networked.
Multi-Port Repeater An
Ethernet wiring center that allows multiple devices to be attached
at one point on an Ethernet. A Managed Multi-Port Repeater has
network management capabilities.
Multiplexer A device
that can send several signals over a single line. They are then
separated by a similar device at the other end of the link. This
can be done in a variety of ways: time division multiplexing,
frequency division multiplexing and statistical multiplexing.
Multiplexers are also becoming increasingly efficient in terms
of data compression, error correction, transmission speed and
multi-drop capabilities.
Multi-tasking The
concurrent execution of two or more tasks or the concurrent use
of a single program that can carry out many functions.
