Enable MAC address move notifications
The outgoing interface for a MAC address entry learned on interface A is changed to interface B when the following conditions exist:
Interface B receives a packet with the MAC address as the source MAC address.
Interface B belongs to the same VLAN as interface A.
In this case, the MAC address is moved from interface A to interface B, and a MAC address move occurs.
If a MAC address is continuously moved between the two interfaces, Layer 2 loops might occur. To detect and locate loops, you can view the MAC address move information.
When the system detects that a MAC address frequently moves from an interface, you can configure MAC address move suppression on the interface to bring it down. The interface can automatically come up after waiting for the specified suppression interval. Or, you can manually bring up the interface. To make MAC address move suppression take effect, you must use this feature together with ARP fast update. For more information about ARP fast update, see "Enabling ARP fast update for MAC address moves."
To display the MAC address move records after the device is started, use the display mac-address mac-move command.
To enable MAC address move notifications:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enable MAC address move notifications and optionally specify a detection interval. | mac-address notification mac-move [ interval interval-value ] | By default, MAC address move notifications are disabled. If you do not specify a detection interval, the default setting of 1 minute is used. After you execute this command: If the device is configured with the snmp-agent trap enable mac-address command, the system sends SNMP notifications to the SNMP module.
|
3. Set a threshold for MAC address moves sourced from an interface within a detection interval. | mac-address notification mac-move suppression threshold threshold-value | The default setting is 3. |
4. Set a MAC address move suppression interval. | mac-address notification mac-move suppression interval interval-value | The default setting is 30 seconds. |
5. Enter interface view. |
| N/A |
6. Enable MAC address move suppression. | mac-address notification mac-move suppression | By default, MAC address move suppression is disabled. |
7. Return to system view. | quit | N/A |
8. Enable ARP fast update for MAC address moves. | mac-address mac-move fast-update | This task is required when you enable MAC address move suppression. By default, ARP fast update for MAC address moves is disabled. |