The value of tLagholdTimeDown specifies the timer in 0.1 second
units which controls the delay between detecting that a LAG is down
(all active ports are down) and reporting it to the higher levels.
The default value for this timer is 0, i.e. the higher levels are
informed directly.
A non zero value may be configured e.g. when active/standby
signalling is used in a 1:1 fashion to avoid that the higher levels
are informed during the small time interval between detecting that
the LAG is down and the time needed to activate the standby system.