25.1.7 Clearing MAC Address Table

The Switch clears the MAC address table through operation commands and protocol usage.

The following tables show the triggers for clearing MAC learned entries by VLAN.

Table 25-3 Opportunity to clear the MAC address table
Trigger	Description
Port down*1	Learned entries are deleted from the corresponding port.
Channel Group Down*2	Learned entries are deleted from the corresponding channel group.
Execution of the clear mac-address-table operation command	The MAC address table is cleared according to the parameters.
Clear MIB set for the MAC address table (private MIB)	The MAC address table is cleared at setup.
Spanning Tree topology changed	When Spanning Tree Protocols are configured on the Switch: The MAC address table is cleared when a topology change is detected.
Spanning Tree topology changed	When the Switch runs as a ring node in a network configuration using a Spanning Tree Protocol and Ring Protocol: The MAC address table is cleared when a flush control frame sent during a topology change for a switch using the Ring Protocol is received.
GSRP master/backup switched	The MAC address table is cleared when the GSRP Flush request frame sent when the GSRP switch becomes the master is received.
Route switched by the Ring Protocol	When the Switch runs as the master node: The MAC address table is cleared when path switching is performed.
	When the Switch runs as a transit node: The MAC address table is cleared when the flush control frame sent from the master node when path switching is performed is received. The MAC address table is cleared when the maintenance time for waiting for the flush control frame times out.
	When the multi-fault monitoring functionality is enabled, if receiving flush control frames sent from a shared node when switching to or switching back from a backup ring, the MAC address table is cleared.
	The MAC address table is cleared when the neighboring-ring flush control frame sent from the master node when path switching is performed is received.
Primary port and secondary port switched due to uplink/redundancy functionality	The MAC address table is cleared when the flush control frame sent on switching from the primary port to the secondary port or on switching back from the secondary port to the primary port is received.
Configuring MAC address learning suppression	If MAC address learning suppression is set by using the configuration command no mac-address-table learning, entries learned by the corresponding VLAN are deleted.

#1: Downed ports such as those that are down due to a line failure, execution of the inactivate operation command, or the settings in the shutdown configuration command.
#2: Downed channel groups such as those that are down due to the LACP, a line failure, or the settings in the shutdown configuration command.