VeEX MPA User Manual page 816

MPA_e_manual_D07-00-129P_RevA00
L
Line Overhead
In a Synchronous Transport Frame, 18 bytes are delegated in the Transport Overhead
section of the frame for monitoring and maintenance of the frame signal across a line
span. The Line Overhead data is updated each time the frame passes through a Line
Terminating Equipment. The functions of the Line Overhead include the Payload Pointer
bytes, a parity byte, Automated Protection Switching signaling, a data communications
channel for message based administration, monitoring, maintenance, alarm and other
communications needs between line terminating equipment, and an order-wire channel
for voice communications between line terminating equipment.
Line Terminating Equipment (LTE)
Equipment, at either end of a Line span in a SONET network that originates the Line
Overhead or terminates the Line Overhead.
Live (RX Pattern)
Expects the received payload date to be random and unpredictable, as is the case with
live traffic. When selected, payload Bit errors and Pattern Sync alarms are not
monitored and their LEDs becomes non-functional.
LOCS
Loss of Client Signal
Loss of Frame (LOF)
A Loss of Frame is declared when an OOF (Out of Frame) condition has existed for a
certain period of time, which can vary depending on the protocol being tested.
Loss of Frame Defects
Loss of Frame Defects, in SONET, is synonymous to Out of Frame (OOF).
LOF-P
Loss of Frame - Path.
LOFS
Loss of Frame Seconds.
LOF-V
Loss of Frame - Virtual Tributary.
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