Operations Manual
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LAN EMULATION CLIENT (LEC)—ATM Forum-defined specifications in support of
LAN-to-LAN connectivity, called LAN Emulation. LEC defines that set of functions
implemented in a LAN DTE to interface with an ATM network in support of LAN
Emulation.
LAN EMULATION SERVER (LES)—LES defines that set of functions implemented
in an ATM network in support of LAN-to-LAN connection establishment.
LAN EMULATION CONFIGURATION SERVER (LECS)—LECS defines that set of
functions implemented in an ATM network that provide LAN DTEs with information
regarding the location of the other LAN Emulation services.
LINK SEGMENT—The link segment of coaxial cable is a segment that has no MAU
devices, but links together two LAN devices such as repeaters.
LINK TEST—In 10Base-T Ethernet there is a link test function that validates the UTP
link. This consists of a pulse transmitted from point A on one pair that is validated at
point B. Point B also transmits a pulse on the second pair to be validated by point A.
These pulses occur during media idle states (in between packets).
LOCAL AREA NETWORK (LAN)—A type of limited-area broadcast network in which
devices attached to a common transmission medium.
MEDIA ACCESS CONTROL (MAC)—IEEE specifications for the lower half of the
data link layer (layer 2) that defines topology-dependent access control protocols for
IEEE LAN specifications.
MANAGEMENT AGENT—Software that is used to view system activity and set
system variables.
MAU—See Medium Attachment Unit
MAU-to-MAU, HUB-to-HUB WIRING—10Base-T MAU-to-MAU or hub-to-hub
wiring generally requires a crossover cable located somewhere along the UTP cable run.
This may commonly occur at the punch-down block or between the RJ45 wall receptacle
and the workstation.
MAU/TRANSCEIVER—An Ethernet transceiver is a MAU. A 10Base-T MAU
interfaces the UTP media to an AUI port on a workstation, repeater, bridge or other
Ethernet device.
MDI/MDI-X—See Medium Dependent Interface
MEDIUM ATTACHMENT UNIT (MAU)—In a LAN, a device used in a data station
to couple the DTE to the transmission medium.
MEDIUM DEPENDENT INTERFACE (MDI)—The mechanical and electrical
interface between the trunk cable medium and the MAU. MDI-X is another version of
the interface that enables like devices to connect using different pin-outs, thereby
avoiding conflicts that occur when receiving and transmitting packets use the same pin-
out.
MANAGEMENT INFORMATION BASE (MIB)—A data base of network
configuration and performance information. The formal definition of a MIB includes the
names of the objects it contains and the type of information retained. Management
protocols such as SNMP and CMIP contain procedures for acquiring and exchanging
MIB information.
MULTIMODE FIBER—Type of fiber optic cable used for transmitting data over
relatively short distances (maximum 2 km). The fiber contains two materials with
different refractive indices and uses reflection to propagate a relatively low-intensity
signal (Class 3 or equivalent).
NETWORK SERVICES ACCESS POINT (NSAP)—OSI generic standard for a
network address consisting of 20 octets. ATM has specified E.164 for public network
addressing and the NSAP address structure for private network addresses.
