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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

Alarm

Description

Physical

pll

Phase-locked loop out of lock

lol

Loss of light

Section

lof

Loss of frame

los

Loss of signal

Line

ais-l

Alarm indication signal—line

rfi-l

Remote failure indication—line

ber-sd

Bit error rate defect-signal degrade

ber-sf

Bit error rate fault-signal fail

Path

ais-p

Alarm indication signal—path

locd (ATM only)

Loss of cell delineation

lop-p

Loss of pointer—path

plm-p

Payload (signal) label mismatch

rfi-p

Remote failure indication—path

uneq-p

Path unequipped

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:

  • AIS-L

  • LOF

  • PLL

  • RFI-L

  • RFI-P