Allied Telesis AT-S25 - Manual (Page 82)

82
MAC Address Table
The MAC address table (also referred to as the forwarding table) is a
snapshot of source MAC addresses that a switch has learned and stored
in its volatile memory. When a frame is received by a port on a switch,
the source address of the frame is inspected to determine whether or
not the address is already in the table. If it is not, the switch adds the
address to the table.
To prevent the table from becoming filled with addresses of devices that
have become inactive and are no longer sending frames, MAC address
are periodically deleted from the table. An address is deleted if a MAC
address in the table does not reappear on any port after a specified
period of time has elapsed. The default time period is 300 seconds (5
minutes). This aging time is configurable, as explained in the procedure
Changing the Aging Time of the MAC Address Table on page 86.
If you reset the switch or remove power, the table is cleared but
immediately gets updated as soon as the switch is operational and the
ports start to detect MAC addresses in incoming packets.
Each switch in a stack also maintains a static MAC address table. This
table contains MAC addresses that are entered manually and are not
aged out after a period of time. The only way that a static address is
removed is if it is manually deleted from the table. When you enter a
static address, you specify the port when the node with the address is
connected. Each switch in a stack is responsible for maintaining its own
static MAC address table.