SONET/SDH Defect Triggers Overview
A trigger is a defect alarm that causes a physical interface to be marked down. By default, all defects are honored with no hold time. For SONET/SDH and ATM over SONET/SDH interfaces only, you can configure individual triggers to ignore a defect, honor a defect, and apply up and down hold timers to the defect.
Table 1 lists the defects you can configure.
Table 1: SONET/SDH and ATM Active Alarms and Defects
Phase-locked loop out of lock
Loss of light
Loss of frame
Loss of signal
Alarm indication signal—line
Remote failure indication—line
Bit error rate defect-signal degrade
Bit error rate fault-signal fail
Alarm indication signal—path
locd (ATM only)
Loss of cell delineation
Loss of pointer—path
Payload (signal) label mismatch
Remote failure indication—path
If you configure a defect to be ignored, that defect does not contribute to the interface being marked down or up.
After you configure a defect to be ignored, the Junos OS reevaluates the state of the defect on the interface. If the defect is outstanding and has caused the interface to be marked down, the interface is marked up.
When you configure a trigger on a low-level defect—for example, an LOS—only the low-level defect is affected. Higher-level defects that might result from the lower-level defect are not affected by the low-level trigger configuration. Therefore, you must configure higher-level defects as well.
You can prevent a loss of signal (LOS) from bringing down an interface. An LOS can lead to the following defects: