Configuring The Aging Timer For Dynamic Mac Address Entries; Configuring The Mac Learning Limit On Ports - H3C S5120-EI Configuration Manual

To do...
Enable global MAC
address learning
Enter interface view or
port group view
Disable MAC address
learning on the interface
or all ports in the port
group
NOTE:
When MAC address learning is disabled, the obtained MAC addresses remain valid until they age out.
•
• For configuration about port groups, see the chapter "Ethernet interface configuration."

Configuring the aging timer for dynamic MAC address entries

The MAC address table uses an aging timer for dynamic MAC address entries for security and efficient
use of table space. If a dynamic MAC address entry has failed to update before the aging timer expires,
the device deletes the entry. This aging mechanism ensures that the MAC address table can quickly
update to accommodate the latest network changes.
Set the aging timer appropriately. Too long an aging interval might cause the MAC address table to
retain outdated entries, exhaust the MAC address table resources, and fail to update its entries to
accommodate the latest network changes. Too short an interval might result in removal of valid entries,
causing unnecessary broadcasts, which might affect device performance.
Follow these steps to configure the aging timer for dynamic MAC address entries:
To do...
Enter system view
Configure the aging timer
for dynamic MAC address
entries
You can reduce broadcasts on a stable network by disabling the aging timer to prevent dynamic entries
from unnecessarily aging out. By reducing broadcasts, you improve not only network performance, but
also security, because you reduce the chances that a data packet will reach unintended destinations.

Configuring the MAC learning limit on ports

To prevent the MAC address table from getting too large, you can limit the number of MAC addresses
that a port can obtain.
Use the command...
undo mac-address mac-learning
disable
•
Enter Layer 2 Ethernet interface
view or Layer 2 aggregate
interface view:
interface interface-type
interface-number
•
Enter port group view:
port-group manual port-group-name
mac-address mac-learning disable
Use the command...
system-view
mac-address timer
{ aging seconds |
no-aging }
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Remarks
Optional
Enabled by default.
Required
Use either command.
Settings in Layer 2 Ethernet interface view
or Layer 2 aggregate interface view take
effect on the interface only. Settings in
port group view take effect on all member
ports in the port group.
Required
Enabled by default.
Remarks
—
Optional
300 seconds by default.
The no-aging keyword disables the aging timer.