3Com Switch 8800 Configuration Guide Chapter 44 MAC Address Table Management44-3If aging time is set too short, the Ethernet switch may delete valid MAC address table.You can use the following commands to set the MAC address aging time for thesystem.Perform the following configuration in system view.Table 44-2 Set the MAC address aging time for the systemOperation CommandSet the dynamic MAC address agingtimemac-address timer { aging age |no-aging }Restore the default MAC addressaging time undo mac-address timer agingIn addition, this command takes effect on all the ports. However the address aging onlyfunctions on the dynamic addresses (the learned or configured as age entries by theuser).By default, the aging-time is 300 seconds. With the no-aging parameter, the commandperforms no aging on the MAC address entries.Caution:The dynamic MAC address aging is completed during the second aging cycle.44.3 Maximum MAC Address Number Learned by EthernetPort and Forwarding Option ConfigurationWith MAC address learning, an Ethernet switch can obtain MAC addresses of everynetwork devices on network segments connecting to a port. As for packets destined tothose MAC addresses, the switch directly uses hardware to forward them. An overlargeMAC address table may cause the low forwarding performance of the switch.You can control the number of entries of the MAC address table by setting themaximum number of MAC addresses learned by a port. if you set the value to count,and when the number of MAC addresses learned by the port reaches this value, thisport will no longer learn any more MAC addresses.You can also set the switch to drop corresponding packets when the number of MACaddresses learned by the port exceeds the configured threshold.
