Devices Using MAC Address Lockdown shows three devices (A, B, and C) connected through a hub to an Extreme Networks device with MAC lockdown timeout configured on the ports.
When each device starts sending traffic, the source MAC address of the device is learned and FDB (forwarding database) entries are created. The MAC lockdown timer is set at 100 seconds.
As long as a device continues to send traffic, the MAC entry for that device is refreshed, and the MAC lockdown timer corresponding to the MAC entry is refreshed.
Therefore, as long as the device is active, the timer does not expire. The traffic can be continuous or can occur in bursts within the MAC lockdown timeout duration for the port.
In this example, Device A starts sending traffic. When the MAC address of Device A is learned and added to the FDB, the MAC lockdown timer is started for this entry.
Device A stops sending traffic and resumes sending traffic after 50 seconds have elapsed. At this point the MAC entry for Device A is refreshed and the MAC lockdown timer is restarted.
When a device stops sending traffic and does not resume within the MAC lockdown timer interval for the port, the MAC lockdown timer expires, and the MAC entry is removed from the FDB.
In this example, Devices A, B, and C start sending traffic. As each MAC address is learned, the MAC lockdown timer is started for each entry.
Device A stops sending traffic; Devices B and C continue sending traffic. After 100 seconds, the MAC lockdown timer for the Device A entry is removed from the FDB. Because Devices B and C have continued to send traffic, their MAC entries continue to be refreshed and their MAC lockdown timers continue to be restarted.
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