3Com WX3000 Setting the Aging Time of MAC Address Entries, Mac-address timer aging, Age no-aging

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 device.

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If the aging time is too long, excessive invalid MAC address entries maintained by the device 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 device may remove valid MAC address entries. This decreases the forwarding performance of the device.

Follow these steps to set the aging time of MAC address entries:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set the aging time of MAC	mac-address timer { aging	Required
		The default aging time is 300
address entries	age no-aging }
		seconds.

Normally, you are recommended to use the default aging time, namely, 300 seconds. The no-agingkeyword 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 the device to acquire the MAC addresses of the network devices on the segment connected to the ports of the device. By searching the MAC address table, the device 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 device.

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

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