This indicates that the

Shivu b · ‎09-27-2016

Hi All,

I am observing below errors on cisco 3750v 24 PS switch.

Could you please suggest what can be done to fix the issue.

I have done shut and unshut and unplug and plug back SFP..

Logs:

====

Sep 27 07:56:48: %SFF8472-5-THRESHOLD_VIOLATION: Gi1/0/1: Rx power low warning; Operating value: -18.0 dBm, Threshold value: -17.0 dBm.
Sep 27 08:06:48: %SFF8472-5-THRESHOLD_VIOLATION: Gi1/0/1: Rx power low warning; Operating value: -18.0 dBm, Threshold value: -17.0 dBm.
Sep 27 08:16:48: %SFF8472-5-THRESHOLD_VIOLATION: Gi1/0/1: Rx power low warning; Operating value: -18.0 dBm, Threshold value: -17.0 dBm.
Sep 27 08:26:48: %SFF8472-5-THRESHOLD_VIOLATION: Gi1/0/1: Rx power low warning; Operating value: -17.9 dBm, Threshold value: -17.0 dBm.

MFRA-MDF-C3750-34.13# sh int transceiver detail
mA: milliamperes, dBm: decibels (milliwatts), NA or N/A: not applicable.
++ : high alarm, + : high warning, - : low warning, -- : low alarm.
A2D readouts (if they differ), are reported in parentheses.
The threshold values are calibrated.

                              High Alarm High Warn Low Warn   Low Alarm
          Temperature         Threshold   Threshold Threshold Threshold
Port       (Celsius)          (Celsius)   (Celsius) (Celsius) (Celsius)
--------- ------------------ ---------- --------- --------- ---------
Gi1/0/1     27.8                90.0        85.0        -5.0      -10.0

                              High Alarm High Warn Low Warn   Low Alarm
           Voltage            Threshold   Threshold Threshold Threshold
Port       (Volts)            (Volts)     (Volts)    (Volts)    (Volts)
--------- ---------------    ---------- --------- --------- ---------
Gi1/0/1    3.27                  3.60        3.50        3.10       3.00

           Optical            High Alarm High Warn Low Warn   Low Alarm
           Transmit Power     Threshold   Threshold Threshold Threshold
Port       (dBm)              (dBm)       (dBm)      (dBm)      (dBm)
--------- ----------------- ---------- --------- --------- ---------
Gi1/0/1     -4.9                 0.0        -3.0        -9.5      -13.5

           Optical            High Alarm High Warn Low Warn   Low Alarm
           Receive Power      Threshold   Threshold Threshold Threshold
Port       (dBm)              (dBm)       (dBm)      (dBm)      (dBm)
-------    ----------------- ---------- --------- --------- ---------
Gi1/0/1    -17.6         -       3.0         0.0       -17.0      -21.0

-------------------------------------------------------------------------------

System image file is "flash:/c3750-ipbasek9-mz.122-55.SE7/c3750-ipbasek9-mz.122-55.SE7.bin"

Iulian Vaideanu · ‎09-28-2016

This indicates that the received optical power level is a bit too low - if it continues to drop towards the alarm threshold you'll start getting input / CRC errors on the switch interface, which further means packet loss...

Cleaning FO connectors and checking / replacing FO patches might help; also, an end-to-end OTDR measurement of the fiber could locate significant attenuations on the path (caused maybe by poor welding, stressed / deteriorated fiber, faulty / dirty intermediary patches / connectors, etc.) which would need to be investigated and fixed.

If nothing obvious is found then using longer range SFPs is also an option.

Shivu b · ‎09-28-2016

Hi Iulian,

Thanks for your reply.

SFP : THRESHOLD_VIOLATION: Gi1/0/1: Rx power low warning;