Link Level The second level of a layered architecture. The purpose of the
level is to provide the functional and procedural means to
establish, maintaining, and release data links. The level also
provides techniques to recover from transmission errors and
other abnormal conditions such as invalid or no responses and
lost of synchronization.
Local Access and Transmit Area (LATA)
A defined geographical area where equal access end offices
and/or access tandem offices can provide carrier access to the
local exchange.
Local Area Network (LAN)
A high-volume data transmission facility interconnecting a
number of data devices, generally within a building or a
campus.
Logical Channel (LC) A point-to-point data communication path that shares a physical
transmission medium via packet interleaved statistical
multiplexing. In packet switching, a packet typically contains a
logical channel number that identifies the packet with a
particular virtual call.
Logical Connection A communication relationship between two end points that
utilizes a virtual circuit connection between the associated
Network Addressable Entities (NAEs).
Loop (Local) Telephone terminology that refers to the local connection
between a network switch and the subscribers end instrument.
Loop (Routing) The undesirable condition in a network where traffic gets
routed in a circular path due to an anomaly of the software or
address information.
LU Line Unit.
Main Distributing Frame (MDF)
The interconnect between the outside plant facilities and the
C.O. wire.
Mbps Megabytes per second.
MCC Master Control Center.
MCTSI Module Controller/Time Slot Interchanger. A device on the DRM
which performs the time switching function.
MDF Main Distributing Frame.
Messages The logical unit of information passed between two session level
protocol entities. A block of text that the user of a
communication network wishes to have transported as a whole.
The unit of communication as seen by the user may be
segmented into several packets to traverse the network. In some
circumstances, several messages can be carried in one packet.
MHD Moving Head Disk.
MHEIB Message handler Ethernet Interface Bus.
MMSU Modular Metallic Service Unit.
Modem MOdulator-DEModulator. A device that allows digital signals to
be transmitted over analog facilities.
235-200-150
May 2003
GLOSSARY
Issue 3.00 Page G-7
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