MAC Address Table Management 453Setting MAC Address Aging TimeSetting an appropriate aging time implements MAC address aging. Too long or tooshort an aging time set by subscribers will cause the Ethernet switch to flood a largeamount of data packets. This affects the switch operation performance.If the aging time is set too long, the Switch will store a great number of out-of-dateMAC address tables. This will consume MAC address table resources and the Switchwill not be able to update the MAC address table according to the network change.If the aging time is set too short, the Switch may delete valid MAC address tableentries.You can use the following commands to set the MAC address aging time for thesystem.Perform the following configuration in System View.Table 498 Set the MAC Address Aging Time for the SystemIn addition, this command takes effect on all the ports. However the address agingonly functions on the dynamic addresses (manual entries added to the Switch are notaged).By default, the aging-time is 300 seconds. With the no-aging parameter, thecommand performs no aging on the MAC address entries.Setting the Max Count of MAC Addresses Learned by a PortWith the address learning function, a Switch can learn new MAC addresses. After itsreceived a packet destined for an already learned MAC address, the Switch willforward it directly with the hardware, instead of broadcasting it. However, too manyMAC address items learned by a port will affect the Switch operation performance.You can control the MAC address items learned by a port through setting the maxcount of MAC addresses learned by a port. If a user sets the max count value of a portas count, the port will not learn new MAC address items when the count of MACaddress items reaches the count value.You can use the following commands to set the max count of MAC addresses learnedby a port.Perform the following configuration in Ethernet Port View.Table 499 Set the Max Count of MAC Address Learned by a PortBy default, there is no limit to the MAC addresses learned using the Ethernet port.Operation CommandSet the dynamic MAC address aging time mac-address timer { aging age |no-aging }Restore the default MAC address aging time undo mac-address timer agingOperation CommandSet the Max Count of MAC AddressLearned by a Portmac-address max-mac-count countRestore the default Max Count of MACAddress Learned by a Portundo mac-address max-mac-count
