LB (Leaky Bucket). A term used as an analogous
description of the algorithm used for conformance checking of cell flows
from a user or network. The "leaking hole in the bucket" applies to
the sustained rate at which cells can be accommodated, while the "bucket
depth" applies to the tolerance to cell bursting over a given time period.
LAI (Location Area Identity). LAI identifies
a location area.
LAN (Local Area Network). A group of computers and associated
devices that share a common communications link and typically share the resources
of a single server within a small geographic area (for example, an office).
Land line. The telephone service or
(PSTN).
Land mobile service. A bidirectional
radio service within the 44-50 MHz bandwidth.
Latency. A term used to typically describe
delays in a network. For example, congestion, routing etc.
Layer. The open system interconnection
(OSI) model of seven layers that defines
the protocols for data
communications.
Layer 1. In the (OSI)
model, the physical layer which represents the hardware used for communication.
Layer 2. In the (OSI)
model, the datalink layer is concerned with the optimization of data
for transmission.
Layer 3. In the (OSI)
model, the network layer is concerned with the routing and switching
of data from its source to its destination.
Layer 4. In the (OSI)
model, the transport layer which represents the processes involved in
establishing connections throughout the network and the control of the
transmission of data within the network.
Layer 5. In the (OSI)
model, the session layer is concerned with establishing a connection
between communication devices. This layer is also responsible for the
termination of a conversation/session when the devices have finished
communicating.
Layer 6. In the (OSI)
model, the presentation layer is concerned with the presentation of
data at the receiving end of the link. It is responsible for the encryption/decryption
of data and data compression.
The presentation layer is primarily concerned with passing data into
the network in a suitable format.
Layer 7. In the (OSI)
model, the application layer which contains the user applications.
The application layer is the interface
between the user and the communications technology.
L-band. The bandwidth
of the electromagnetic
spectrum used for satellite and microwave communication signals.
LCD (Liquid Crystal Display).
LIFO (Last In/First Out). A queueing technique
where the last entry to the queue is the first to be removed.
Link. An entity that defines a topological
relationship (including available transport capacity) between two nodes
in different sub-networks. Multiple links may exist between a pair of
sub-networks. It is synonymous with logical link.
Local exchange area. The part
of the national land telephone network controlled by the local telephone
operating company.
LEC (Local exchange carrier).
A landline telephone company serving a local area.
LNA (Low Noise Amplifier). An amplifier that add very little noise to a signal. It
is often used as a preamplifier at the input of a receiver.
Location Area. A group of
cells uniquely identified by its Location Area Identity (LAI) number.
Location updating. When the
mobile station is roaming, it is continually listening to the control
channel from the base transceiver station (BTS),
which is transmitting the location area identity (LAI).
When the mobile station enters a new location
area or MSC service area, it recognizes a new LAI and will inform
the network, the VLR and HLR,
of its new location. This is known as location updating.
Loopback test. A circuit test of
any device involved in the transmission or reception of signals to ensure
it is in working order and that the device and the interface
are working together.