Available - is a combination of both up time and no data (unknown).


No Data (unknown) is the period that the system was unable to retrieve any data from the device and as a result the availability status for the link was unknown and is added along with uptime to the availability stats.


Up - The period of time or percentage that the data retrieved from the device indicated that the link was physically up.


Down - The period of time or percentage that the data retrieved from the device indicated that the link was physically down.