Symptom

ASR903 may report incorrect optical power thresholds for QSFP-40G-SR4 resulting in following logs - %SFF8472-3-THRESHOLD_VIOLATION: Fo0/4/1: Tx power low warning; Operating value: -2.3 dBm, Threshold value: -1.6 dBm. %SFF8472-3-THRESHOLD_VIOLATION: Fo0/4/0: Tx power low warning; Operating value: -2.1 dBm, Threshold value: -1.6 dBm. "show hw-module subslot x/x transceiver x idprom detail" shows correct threshold values. #sh hw-module subslot 0/4 transceiver 1 idprom detail LANES THRESHOLDS high alarm high warning low warning low alarm Transmit power mW 001.5848 000.7943 000.1737 000.0691 <- The Tx optical power low warning threshold here is -7.6dBm Receive power mW 002.1877 001.7378 000.1122 000.0446 Manually converted the above values into dBm LANES THRESHOLDS high alarm high warning low warning low alarm Transmit power mW 001.5848 000.7943 -7.6 -11.6 Receive power mW 002.1877 001.7378 -9.5 -13.5 Expected thresholds for QSFP-40G-SR4 - Transmit Power (dBm) Maximum -1, per lane* Minimum -7.6, per lane Receive Power (dBm) Maximum 2.4, per lane Minimum -9.5, per lane 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

Conditions

Seen with QSFP-40G-SR4

Workaround

Further Problem Description