Setting The Aging Time Of Mac Address Entries; Setting The Maximum Number Of Mac Addresses A Port Can Learn - H3C S5100-SI Operation Manual

Setting the Aging Time of MAC Address Entries

Setting aging time properly helps effective utilization of MAC address aging. The aging time that is too
long or too short affects the performance of the switch.
If the aging time is too long, excessive invalid MAC address entries maintained by the switch may
fill up the MAC address table. This prevents the MAC address table from being updated with
network changes in time.
If the aging time is too short, the switch may remove valid MAC address entries. This decreases the
forwarding performance of the switch.
Table 1-5 Set aging time of MAC address entries
Operation
Enter system view
Set the aging time of MAC
address entries
Normally, you are recommended to use the default aging time, namely, 300 seconds. The no-aging
keyword specifies that MAC address entries do not age out.
MAC address aging configuration applies to all ports, but only takes effect on dynamic MAC addresses
that are learnt or configured to age.

Setting the Maximum Number of MAC Addresses a Port Can Learn

The MAC address learning mechanism enables an Ethernet switch to acquire the MAC addresses of
the network devices on the segment connected to the ports of the switch. By searching the MAC
address table, the switch directly forwards the packets destined for these MAC addresses through the
hardware, improving the forwarding efficiency. A MAC address table too big in size may prolong the time
for searching MAC address entries, thus decreasing the forwarding performance of the switch.
By setting the maximum number of MAC addresses that can be learnt from individual ports, the
administrator can control the number of the MAC address entries the MAC address table can
dynamically maintain. When the number of the MAC address entries learnt from a port reaches the set
value, the port stops learning MAC addresses.
Table 1-6 Set the maximum number of MAC addresses a port can learn
Operation
Enter system view
Enter Ethernet port view
Command
system-view
mac-address timer { aging
age | no-aging }
Command
system-view
interface interface-type
interface-number
1-6
Description
—
Required
The default aging time is 300
seconds.
Description
—
—