3com 4210 PWR 9-Port 3CR17341-91-ME 用户手册

C

HAPTER

 13: MAC A

DDRESS

 T

ABLE

 M

ANAGEMENT

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.

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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.

To verify your configuration, you can display information about the MAC address 
table by executing the display command in any view.

Table 92   Set aging time of MAC address entries

Enter system view 

system-view 

- 

Set the aging time of MAC 
address entries 

mac-address timer { aging 
age | no-aging } 

Required

The default aging time is 300 
seconds.

Table 93   Set the maximum number of MAC addresses a port can learn

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.

Table 94   Display MAC address table information

Display information about the 
MAC address table 

display mac-address [ 
display-option ] 

The display command can be 
executed in any view. 

Display the aging time of the 
dynamic MAC address entries 
in the MAC address table