3Com 4210 9-Port - Setting the Maximum Number of MAC Addresses a Port Can Learn; Displaying MAC Address Table Information

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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 learned 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.
With the port MAC address configuration, the switch uses the MAC address of a port as the source
MAC address when sending the following Layer 2 PDUs out of the port:
z LACP
z STP
z NDP/NTDP
z GVRP
z DLDP
Port MAC address configuration does not affect service packet forwarding.
Displaying MAC Address Table Information
To do… Use the command… Remarks
Display information about the
MAC address table
display mac-address [ display-option ]
Display the aging time of the
dynamic MAC address entries
in the MAC address table
display mac-address aging-time
Available in any view