MAC Address Table

Data traffic is flooding

Data is not getting forwarded, instead it is being flooded to all ports of a VLAN.

Possible Cause

MAC address learning is disabled because of loop detection. A severity 2 syslog message, STM_LOOP_DETECT, should have been received.

Solution

After waiting for 180 seconds, learning is enabled automatically. A severity 2 syslog message, STM_LEARNING_RE_ENABLE, should be received.

Possible Cause

The MAC address table is full. A severity 2 syslog message, STM_LIMIT_REACHED, should have been received.

Solution

After waiting for 180 seconds, the MAC table is flushed and learning is enabled automatically.

Alternatively, wait until some MAC entries are aged out, so that the total learned entries fall below 1500, or enter the clear mac address-table dynamic [address <mac>] command to clear out entries. This creates free space for new MAC entries to be learned. A severity 2 syslog message, STM_LEARNING_RE_ENABLE, should be received.

Possible Cause

MAC address learning is disabled due to a learning overload (that is, too many new addresses in a short time). A severity 4 syslog message, STM_LEARNING_OVERLOAD, should have been received.

Solution

After waiting for 120 seconds, learning is enabled automatically.