Cabletron Systems 1800 M, N, O, P

Glossary glo- 7
M
MAC stands for “medium access control,” which is the second layer in the three-layer ISO
LAN protocol hierarchy. (The first layer is Physical and the third is LLC; LLC is
descri bed i n this g lossa ry.) M AC supp orts medium -depen dent fu nctions , and uses t he
services of the physical layer to provide services to LLC.
M-Bit is the “more data” bit in an X.25 packet, and indicates that more information related
to the packet will follow.
Modem
stands for Modulator-demodulator, which is a device u sed to convert serial digital data
into a signal suitable for transm ission ov er a tele ph one line an d to reco nvert th e analo g
signal from the phone line back into serial digital data.
N
Netlink
is the family name of Cabletron’s FRX4000 and FRX6000 frame relay access
products, as well as the name of Cabletron’s proprietary MIB that applies to the
FRX4000, FRX6000, SmartSwitch 1800, and Frame Relay Module.
Network
is a series of points connected by communications channels.
NMVT stands for “network management v ector transpor t,” which is an IBM s ervice enco ding
used in sessions between a control point and a PU (physical unit).
Node is a physical device that acts as a transfer point for data between endpoints of a
physical/logical connection. SmartSwitch 1800s and other Cabletron frame re lay
access devices are often referred to as nodes.
O
OPX stands for Off Premise Extension. When configured for this option, a voice/FAX
module operates in loop start mode and provides loop current to the attached device.
P
Packet
is a group of data and control signals transmitted as a composite whole across a
packet-switching network.
Packet Switching
is the breaking up of data into smaller p ieces and the transmi ssion of thes e pieces o ver
a network via X.25.