Cisco Router Fiber Optic Levels

Below is a way to check the Tx/Rx Optical power levels on a Cisco router. I have a post on how to check these on Cisco switches.

These are the levels you’re look for:
Tx Power Level: Within 6dB Range between -1 and -7 dBm
Rx Power Level: -1 and -9.9 dBm

If you are seeing the Tx/Rx in the -30 dBm or lower range, it’s usually caused by no cable plugged in and “noise floor“.  Cable faults (poorly seated connectors, dirty connectors, bad splicing, etc..) are usually around -14 dBm or lower.

First look for your 10G interfaces:

cordero-asr01#sh ip int br | inc Te
Interface              IP-Address      OK? Method Status                Protocol
Te0/0/0                100.1.0.1      YES NVRAM  up                    up      
Te0/0/1                10.1.0.1       YES manual up                    up    

Now we can check the levels using the “show hw-module” command:

cordero-asr01#show hw-module subslot 0/0 transceiver 0 status 
The Transceiver in slot 0 subslot 0 port 0 is enabled.
  Module temperature                        = +29.363 C
  Transceiver Tx supply voltage             = 3311.9 mVolts
  Transceiver Tx bias current               = 22906 uAmps
  Transceiver Tx power                      = -2.2 dBm
  Transceiver Rx optical power              = -2.4 dBm

cordero-asr01#show hw-module subslot 0/0 transceiver 1 status 
The Transceiver in slot 0 subslot 0 port 1 is enabled.
  Module temperature                        = +32.957 C
  Transceiver Tx supply voltage             = 3313.6 mVolts
  Transceiver Tx bias current               = 5744 uAmps
  Transceiver Tx power                      = -2.2 dBm
  Transceiver Rx optical power              = -2.7 dBm

Just notice how I use the subslot and transceiver # in the command.