VeEX MPA, User Manual

Page: 312 / 842

SONET Tab
312
LOS Loss of Signal. An all-zeros pattern is transmitted to simulate
a loss of signal or loss of optical power. This forces the
downstream SONET equipment to (1) generate an AIS alarm
to its downstream network elements (NE), and (2) generate
an RDI alarm to its upstream NEs.
LOF Loss of Frame. An all-zeros pattern is inserted into the A1
and A2 framing bytes of the Section OH. This simulates the
absence of a valid framing pattern. This forces the
downstream SONET equipment to generate an AIS alarm to
its downstream network elements (NE) and generate an RDI
alarm to its upstream NEs.
AIS-L Line Alarm Indication Signal. The transmission of an AIS-L to
a downstream NE forces that NE to send an AIS-P alarm to
the next downstream NE. The NE will also send an RDI-L
alarm to its upstream equipment.
An AIS-L simulates an alarm generated by Line terminating
equipment (LTE).
RDI-L Line Remote Defect Indicator. This generates an RDI-L
condition using the K2 byte of the Line OH.
This simulates a downstream NE (in this case the test unit) at
the Line layer, reporting a failure to an upstream NE. The
downstream NE (test unit) has encountered a downstream
failure and is alerting upstream SONET equipment.
To do this, the test equipment intrudes on the K2 byte,
changing the bit pattern. The NE receiving the RDI-L alarm
should detect a change to the K2 byte on the incoming
SONET signal. This forces the downstream NE to generate a
Remote Alarm Indicator (RAI) to its upstream NEs.
LOP-P STS Path Loss of Pointer. This simulates a loss of a valid
STS Pointer. When the downstream NE receives an LOP-P,
it generates a DSn AIS alarm to its downstream equipment
and an RDI-P alarm to its upstream equipment.
AIS-P Path Alarm Indication Signal. The transmission of an AIS-P
to a downstream NE forces that NE to send an AIS alarm to
the next downstream NE. The NE will also send an RDI
alarm to its upstream equipment.
An AIS-P simulates an alarm generated by Path terminating
MPA_e_manual_D07-00-129P_RevA00