Evaluating Port Light Level

[Eagleman]

Hi All,
Can someone please explain to me how light level is determined from the show port command?

===============================================================================
Transceiver Digital Diagnostic Monitoring (DDM), Internally Calibrated
===============================================================================
Value High Alarm High Warn Low Warn Low Alarm
-------------------------------------------------------------------------------
Temperature (C) +34.5 +78.0 +73.0 -8.0 -13.0
Supply Voltage (V) 3.29 3.70 3.60 3.00 2.90
Tx Bias Current (mA) 42.4 85.0 80.0 20.0 15.0
Tx Output Power (dBm) -1.25 2.00 1.00 -7.00 -8.00
Rx Optical Power (avg dBm) -1.88 2.50 2.00 -18.01 -20.00
===============================================================================

Thanks for your great help guys..

[mivens]

It's a feature called "DIgital Diagnostic Monitoring" or sometimes "Digital Optical Monitoring" that needs to be supported by the transceiver that is plugged into the port.

There are sensors in the transceiver and a standardised way that the router asks the transceiver for the data.

[Eagleman]

HI mivens,
Thanks for your great help and the explanation as usual.
What i actually wanted to know is how to determine when the light level is within the acceptable range.
Thanks once again!!

[mivens]

The thresholds are all in that table you posted.

For the optic you're using, you get a low warning if the received light level drops below -18dBm and a high warning if it's above +2dBm.
Anything within the low and high alarm levels is within the specification for the transceiver.

Your received light level is currently -1.88dBm so it's good.

Even if they are in specification, I would still investigate low light level if it is not expected due to the length of the fibre/number of connectors patches etc. Sometimes it can be as simple as a patch not plugged in completely.

[Eagleman]

Hi Mivens, What a supperrrrrrrrrrrrrr Answer????????

Your harmer got in the right place and it sunk the knowledge in the right place in my head...
God bless sir!!