for point to point otn eletrical layer traffic
scenario 1.
remote node client site get r_los , from local node will active ALS and shutdown client laser , router side reply "remote ault " to transmission , otn side detect alarm and report it ;
from local node wdm interface / timeslot get SF/SD ,local node active ALS and shutdown client laser , router side reply "remote ault " to transmission , otn side detect alarm and report it ;
scenario 2 .
for OTN ODUK_SNCP
if transmission node client side get "remote_fault" that means transmission node tributary card send local fault to router .
why tributary card send local fault to router // must be both line (both sncp :working +protection) were down and trigger SNCP down and router side reply remote _fault
