Example for Configuring MAC Address Flapping Detection

Networking Requirements

In Figure 1, a loop occurs on a network because two LSWs are connected in error using a network cable. The loop causes MAC address flapping in the MAC address table of the Switch.

To detect loops in a timely manner, configure MAC address flapping detection on the Switch. This function enables the Switch to detect loops by checking whether a MAC address flaps between interfaces, facilitating troubleshooting.

Figure 1 Configuring MAC address flapping detection

Configuration Roadmap

The configuration roadmap is as follows:

Enable MAC address flapping detection.
Set the aging time of flapping MAC addresses.
Configure an action against MAC address flapping on the interfaces to eliminate loops.

Procedure

Enable MAC address flapping detection.

<HUAWEI> system-view
[HUAWEI] sysname Switch
[Switch] mac-address flapping detection

Set the aging time of flapping MAC addresses.

[Switch] mac-address flapping aging-time 500

Configure the action against MAC address flapping to error-down on GE0/0/1 and GE0/0/2.

[Switch] interface gigabitethernet 0/0/1
[Switch-GigabitEthernet0/0/1] mac-address flapping action error-down
[Switch-GigabitEthernet0/0/1] quit
[Switch] interface gigabitethernet 0/0/2
[Switch-GigabitEthernet0/0/2] mac-address flapping action error-down
[Switch-GigabitEthernet0/0/2] quit

Enable error-down interfaces to go up automatically and set the automatic recovery delay.
```
[Switch] error-down auto-recovery cause mac-address-flapping interval 500
```

Verify the configuration.

When the MAC address learned on the GE0/0/1 moves to GE0/0/2, GE0/0/2 is shut down automatically. Run the display mac-address flapping record command to view MAC address flapping records.

[Switch] display mac-address flapping record
 S  : start time                                                                
 E  : end time                                                                  
(Q) : quit vlan                                                                 
(D) : error down 
-------------------------------------------------------------------------------
Move-Time                 VLAN MAC-Address     Original-Port    Move-Ports   MoveNum
-------------------------------------------------------------------------------
S:2012-04-01 17:22:36     1    0000-0000-0007  GE0/0/1         GE0/0/2(D)   83
E:2012-04-01 17:22:44

-------------------------------------------------------------------------------
Total items on slot 0: 1

Configuration Files

Switch configuration file

#
sysname Switch
#                                                                               
error-down auto-recovery cause mac-address-flapping interval 500  
#                                                                               
mac-address flapping aging-time 500    
#
interface GigabitEthernet0/0/1
 mac-address flapping action error-down    
#
interface GigabitEthernet0/0/2
 mac-address flapping action error-down    
#
return