Hello, everyone!
This post is about MCA or OPM board reports CHAN_LOS. Please see more details below.
BACKGROUND
If the MCA or OPM board reports CHAN_LOS, it does not means the lambda has a problem at all. MCA and OPM board scan the lambda of port. Normally there are many lambdas on one port. For one lambda, if you open the lambda monitor function and the power of this lambda is lower than the highest power of lambda 10dB in 10G network(10G/40G/100G mix network is 7dB), board will report CHAN_LOS.
Example
In one 10G WDM network, there are λ1~5，Pλ1=5dB, Pλ2=4dB, Pλ3=4.5dB, Pλ4=3.5dB, Pλ5=-1dB, Pλ1-Pλ5=6dB, if λ5 drop down 4.5dB (λ5=-5.5dB), MCA/OPM will report CHAN_LOS about λ5, but not sure the λ5 was interrupted, if λ2~5 did not changed, but λ1 up to 15dB, all of λ2~5 will report CHAN_LOS.
Of course, not only power changed the board will report CHAN_LOS, if the MCA/OPM board is damaged, maybe it will misreport CHAN_LOS.
