Symptom
ASR903 may report incorrect optical power thresholds for QSFP-40G-LR4 resulting in following logs -
%SFF8472-3-THRESHOLD_VIOLATION: Fo0/5/0: Rx power low warning; Operating value: -8.5 dBm, Threshold value: -7.7 dBm.
"show int FortyGigabitEthernet x/x/x transceiver detail" reports incorrect threshold values.
#sh int fortyGigabitEthernet 0/5/0 transceiver detail
Optical High Alarm High Warn Low Warn Low Alarm
Receive Power Threshold Threshold Threshold Threshold
Port (dBm) (dBm) (dBm) (dBm) (dBm)
--------- ----------------- ---------- --------- --------- ---------
Fo0/5/0 -8.1 9.2 8.2 -7.7 -11.7 <- The Rx optical power low warning threshold here is -7.7dBm
"show hw-module subslot x/x transceiver x idprom detail" shows correct threshold values.
#sh hw-module subslot 0/5 transceiver 0 idprom detail
LANES THRESHOLDS
high alarm high warning low warning low alarm
Transmit power mW 003.3884 001.6982 000.1995 000.0794
Receive power mW 002.1379 001.6982 000.0426 000.0169 <- The Rx optical power low warning threshold here is -13.7dBm
Manually converted the above values in dBm
Transmit power mW 003.3884 001.6982 -7 -11
Receive power mW 002.1379 001.6982 -13.7 -17.7
Expected thresholds for QSFP-40G-LR4 -
Transmit Power (dBm)
Maximum 2.3
Minimum -7
Receive Power (dBm)
Maximum 2.3
Minimum -13.7
Table 7 shows the key optical characteristics for the Cisco QSFP modules.
https://www.cisco.com/c/en/us/products/collateral/interfaces-modules/transceiver-modules/data_sheet_c78-660083.html
Further Problem Description
This bug only addresses the issue on QSFP LR
