H3C Technologies H3C S3600 Series Switches - Manual (Page 239)

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Normally, you are recommended to use the default aging timer, namely, 300 seconds. The no-aging
keyword specifies that MAC address entries never age out.
MAC address aging configuration applies to all ports, but only takes effect on dynamic MAC addresses,
which are either learnt or configured.
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.
Follow these steps to set the maximum number of MAC addresses a port can learn:
To do… Use the command… Remarks
Enter system view system-view —
Enter Ethernet port view
interface interface-type
interface-number
—
Set the maximum number of
MAC addresses the port can
learn
mac-address max-mac-count
count
Required
By default, the number of the
MAC addresses a port can
learn is not limited.
If you have configured the maximum number of MAC addresses that a port can learn, you cannot
enable the MAC address authentication or port security functions on the port, and vice versa.
Enabling Destination MAC Address Triggered Update
By default, a switch updates its MAC address entries based on the source MAC addresses of packets.
However, this may cause the switch to perform unnecessary broadcasts in some applications. For
example, when a port aggregation group is used in an IRF fabric for communications, MAC address
entries of some ports in the aggregation group may not be updated in time, resulting in unnecessary
broadcasts.