RX收光，TX发光
一、交换机
华为交换机命令：
display interface transceiver brief
结果：
......
HW6851
10GE1/0/15 transceiver diagnostic information:
-------------------------------------------------------------------
Temperature (Celsius) :21.30
Voltage (V) :3.33
Bias Current (mA) :5.54
Current RX Power (dBm) :-5.66
Current TX Power (dBm) :-2.16
......
HW6851
10GE1/0/23 transceiver diagnostic information:
-------------------------------------------------------------------
Temperature (Celsius) :23.10
Voltage (V) :3.30
Bias Current (mA) :5.65
Current RX Power (dBm) :-14.18
Current TX Power (dBm) :-2.25
-------------------------------------------------------------------
同时可以查看具体接口：
display interface 10GE 1/0/15 transceiver brief
锐捷交换机：
查看所有光衰：show interface transceiver diagnosis
中兴交换机
查看光衰：
CSW-ZX9908#show opt brief interface xgei-0/3/0/24
If device is externally calibrated, only calibrated values are printed.
-Inf: not applicable, Tx: transmit, Rx: receive.
Optical Optical
Interface Temperature Voltage Voltage Current Tx Power Rx Power
Name (Celsius) (3.3 Volts)(5 Volts) (mA) (dBm) (dBm)
--------------------------------------------------------------------------------
xgei-0/3/0/24 30.01 3.29 N/A 6.31 -1.94 -1.59
二、linux
命令：
ethtool -g 网卡名称，显示网卡的接收/发送环形参数。
lldptool -t -n -i 网卡名称
收光：ethtool -m ens5f0 | grep "Receiver signal" | head -1 | awk -F '/' '{print $2}'
发光：ethtool -m ens5f0 | grep "Laser output power" | head -1 | awk -F '/' '{print $2}'