3Com Switch 4200G Configuration Guide

MAC Address Table Management 95
By setting the maximum numbers of MAC addresses that can be learnt from
individual ports, you can control the number of the MAC address entries the MAC
address table can dynamically maintains. When the number of the MAC address
entries learnt from a port reaches the set value, the port stops learning MAC
addresses.
■ The total number of static MAC addresses and blackhole MAC addresses that can
be configured for a switch is 1,024.
■ The number of static MAC addresses and blackhole MAC addresses depends on
the maximum number of MAC address entries configured for a switch. For
S4200G series switches, the maximum number of MAC addresses entries is 16K.
MAC Address Table
Management
The configuration to manage a MAC address table includes:
■ Configuring a MAC Address Entry and the Aging Time
■ Setting the Maximum Number of MAC Addresses a Port can Learn
Configuring a MAC
Address Entry and the
Aging Time
You can add, modify, or remove one MAC address entry, remove all MAC address
entries concerning a specific port (unicast MAC addresses only), or remove specific
type of MAC address entries (such as dynamic or static MAC address entries).
Setting the Maximum
Number of MAC
Addresses a Port can
Learn
A MAC address table too big in size may decrease the forwarding performance of the
switch. By setting the maximum number of MAC addresses each port can learn, you
can limit the number of MAC address entries a switch maintains. A port stops
learning MAC addresses if the number of MAC addresses it has learnt reaches the set
value.
Table 70 Configure a MAC address entry
Operation Command Description
Enter system view system-view —
Add/modify a MAC
address entry
mac-address { static | dynamic |
blackhole } mac-address
interface interface-type
interface-number vlan vlan-id
Required
Set the aging time for
dynamic MAC address
entries
mac-address timer { aging
seconds | no-aging }
Optional
The default aging time is 300
seconds.
The no-aging keyword specifies
that dynamic MAC address entries
do not age out.
Table 71 Set the maximum number of MAC addresses a port can learn
Operation Command Description
Enter system view system-view —
Enter 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.