| Description | The method used to delete old unused entries
refresh_flag:
The high level sets a flag when it adds or updates an entry,
the Switch clears the flag each time, when it learns the
station once more.
aging_flag:
The high level clears a flag when it adds or updates an entry,
the Switch sets the flag each time, when it learns the station
once more.
aging_time:
The high level defines a timeout, the Switch sends a message
to the high level each time when the station doesn't send
messages during interval between timeout and 2*timeout.
Boundaries:
The Switch doesn't support any mechanism, and the high level
uses two boundaries: red and yellow. When the number of entries
exceeds the red boundary, the high level deletes the oldest entries. |