VeEX MPA, User Manual

Page: 369 / 842

Protocol Tabs
369
Section Section Status LED . Indicates if any of the errors or alarms
within this portion of the overhead are being received,
including a Frame error. This is a status LED.
LOS Loss of Signal . Indicates that a valid SONET signal is not
being received. If an all-zeros pattern exists for 100
milliseconds or longer on the incoming SONET signal, then
an LOS is reported.
LOF Loss of Frame . Indicates that a frame alignment problem
with the incoming SONET signal has been detected. An LOF
is reported if a severely errored framing (SEF) defect
continues for 3 milliseconds or longer. This is alarm LED.
SEF Severely Errored Frame . Declared when four or more
consecutive errored frames are detected on the incoming
SONET signal. This is an alarm LED.
B1 Section Overhead BIP-8 Code Violation . Indicates an error
in the SONET frame. B1 errors are parity errors. The B1 byte
carries the parity information, so a B1 error is a Section error
that applies not only to the Section OH, but the entire frame.
Any error in the frame will result in B1 error. This is an error
LED.
Line Line Status LED . Indicates if any of the errors or alarms
within this portion of the overhead are being received. This is
a status LED.
REI-L Line Remote Error Indicator . Indicates that an error is
occurring at downstream Line terminating equipment. An REI
is also known as a Far-End Block Error (FEBE). The M0 and
M1 bytes of the SONET Line Overhead are used for this
indicator. This is an error LED.
AIS-L Line Alarm Indication Signal . Indicates if an alarm is being
received from upstream Line terminating equipment. This is
an alarm LED.
APS Automatic Protection Switching . Indicates that the K1 and
K2 bytes on the incoming SONET signal have changed.
RDI-L Line Remote Defect Indicator . Indicates that a downstream
defect has occurred along the Line layer. (An RDI is also
known as a Far-End Remote Failure, FERF). This is an alarm
LED.
MPA_e_manual_D07-00-129P_RevA00