Bridge Table Maintenance

E

Aging is used to ensure that the bridge table remains current by removing the stale entries.

The bridging mechanism that is used to ensure that only active entries are in the bridge table is aging, which is denoted by option E.

Bridging is a process used in networking to connect two or more network segments together to form a single network. A bridge is a device that operates at the data link layer of the OSI model and is used to forward data packets between two network segments.

A bridge maintains a bridge table or MAC table, which is a database that contains the MAC addresses of all the devices connected to the bridge. The bridge table is used to make forwarding decisions based on the destination MAC address of the incoming packets.

However, as network topology changes, devices may be added or removed, and their MAC addresses may change. As a result, the bridge table must be constantly updated to ensure that only active entries are present in the table. This is where aging comes into play.

Aging is the process of removing stale entries from the bridge table. Each entry in the bridge table is assigned a timer called the aging time. The aging time specifies how long an entry should remain in the bridge table before it is removed.

When a packet is received by the bridge, the bridge looks up the destination MAC address in the bridge table. If the entry for that MAC address is present in the table, the packet is forwarded to the appropriate port. If the entry is not present in the table, the bridge floods the packet to all the ports except the incoming port.

If an entry in the bridge table is not refreshed within its aging time, it is removed from the table. This ensures that only active entries are present in the bridge table, and the bridge does not forward packets to inactive or non-existent devices.

Therefore, the correct answer is E. aging.