Allied Telesis AT-S39 - Manual (Page 129)

AT-S39 User’s Guide
129
The type of MAC address described above is referred to as a dynamic
MAC address. Dynamic MAC addresses are addresses that the switch
learns by examining the source MAC addresses of the frames received
on the ports.
Dynamic MAC addresses are not stored indefinitely in the MAC address
table. The switch deletes a dynamic MAC address from the table if it does
not receive any frames from the node over a specified period of time.
The switch assumes that the node with that MAC address is no longer
active and that its MAC address can be purged from the table. This
prevents the MAC address table from becoming filled with addresses of
nodes that are no longer active.
The period of time that the switch waits before purging an inactive
dynamic MAC address is called the aging timer. This value is adjustable
on the AT-8024 and AT-8024GB Switches. The default value is 300
seconds (5 minutes). For instructions on changing the aging timer, refer
to Changing the Aging Time on page 139.
The MAC address table can also store static MAC addresses. A static MAC
address, once entered in the table, remains in the table indefinitely and
is never deleted, even when the end node is inactive.
You might need to enter static MAC addresses of end nodes the switch
will not learn in its normal dynamic learning process, or if you want a
MAC address to remain permanently in the table, even when the end
node is inactive.