This object determines what happens to frames with an unrecognized source MAC address once the flow's MAC table has reached its configured maximum: BLOCK discards them, while FORWARD floods them without learning. Admins choose BLOCK to enforce a strict security posture that stops new unknown devices once the table is full, or FORWARD to prioritize connectivity over table growth. For example, a security-conscious admin sets cmMPFlowtableFullAction to BLOCK on an access flow so that once the expected number of devices are learned, any additional rogue device's traffic is dropped rather than flooded.