mac-address flapping detection

MAC address flapping occurs when a MAC address is learned by two interfaces in the same VLAN. The MAC address entry learned later replaces the earlier one.

MAC address flapping occurs in the following situations:

• Network cables of switches are connected incorrectly or switches use incorrect configurations.
• Unauthorized users simulate MAC address of valid network devices to attack the network.

Global MAC address flapping detection enables the Switch to check all MAC addresses. When MAC address flapping occurs, the Switch sends a trap message to the NMS. You can locate the fault according to the trap message. You can also run the display mac-address flapping record command to view MAC address flapping records.

On the S5735-L, S5735S-L, S5735S-L-M, S5735-S, S5735-S-I, and S5735S-S, it takes several seconds to eliminate MAC address flapping if a large number of MAC address flapping events occur on the network. During this period, the number of MAC address flapping records may increase even if MAC address flapping is eliminated.