Locate Bit Error Rate Alarms

Purpose

Bit error rate (BER) alarms are declared when the number of BIP-B2 errors hits a certain threshold. Depending on the threshold, there are two types of BER alarms. In both cases the interface is taken down.

• Bit error rate-signal degrade (BERR-SD) is declared when a bit error rate of 10^-6 is reached.
• Bit error rate-signal failure (BERR-SF) is declared when a bit error rate of 10^-3 is reached.

Action

To display SONET alarms and errors, use the following JUNOS CLI operational mode command:

user@host> show interfaces so-fpc/pic/port extensive

Sample Output

The following sample output displays a BERR-SD error:

user@router2> show interfaces so-1/1/1 extensive

[... Output truncated...]

  Active alarms  : BERR-SD

  Active defects : None

  SONET PHY:            Seconds        Count  State

    PLL Lock                  0            0  OK

    PHY Light                 0            0  OK

  SONET section:

    BIP-B1                   22          101

    SEF                       0            0  OK

    LOS                       0            0  OK

    LOF                       0            0  OK

    ES-S                     22

    SES-S                     0

    SEFS-S                    0

  SONET line:

    BIP-B2                   22          103

    REI-L                     0            0

    RDI-L                     0            0  OK

    AIS-L                     0            0  OK

    BERR-SF                   0            0  OK

    BERR-SD                  11           53  OK

    ES-L                     22

    SES-L                     4

    UAS-L                     2

    ES-LFE                    0

    SES-LFE                   0

    UAS-LFE                   0

  SONET path:

    BIP-B3                   22          166

    REI-P                     0            0

    LOP-P                     0            0  OK

    AIS-P                     0            0  OK

    RDI-P                     0            0  OK

    UNEQ-P                    0            0  OK

    PLM-P                     0            0  OK

    ES-P                     22

    SES-P                     3

    UAS-P                     1

    ES-PFE                    0

    SES-PFE                   0

    UAS-PFE                   0

What It Means

Bit error rates can be caused by any of the following situations:

• Degrading optical fiber
• Optical transmitter or receiver problems
• Dirty fiber-optic connector
• Clocking issues
• Too much attenuation in the optical signal