While viewing the Ethernet switching table, what could lead to a previous entry being removed?

In Ethernet switching, the entries in the MAC (Media Access Control) address table are dynamic and can be removed based on specific conditions. One of the primary reasons for a previously learned MAC address entry to be removed from the Ethernet switching table is when the MAC aging timer expires.

MAC address aging is a mechanism that allows switches to manage their MAC address tables by removing entries that have not been seen for a specific period. When a switch learns a MAC address, it associates that address with a specific port and starts a timer. If there is no traffic from that MAC address on that port within the duration of the aging timer, the entry is considered stale and is removed from the table to free up resources for new entries.

This process helps ensure that the switch does not retain outdated information, allowing it to adapt to changes in the network, such as devices moving between different ports or being powered on or off. Therefore, when the MAC aging timer expires, the entry associated with that MAC address is removed from the Ethernet switching table, making this the correct answer.