How does a network switch determine where to send data?

A network switch determines where to send data by forwarding packets based on MAC (Media Access Control) addresses. When a switch receives a frame of data, it examines the destination MAC address contained within that frame. The switch maintains a MAC address table that keeps track of which MAC addresses it has seen on its various ports. By looking up the destination MAC address in this table, the switch can identify which port to send the data to, ensuring efficient and accurate communication within a local area network (LAN).

This process allows the switch to establish a direct link between the source and destination devices, thereby optimizing network performance by minimizing unnecessary traffic. The ability to make forwarding decisions based solely on MAC addresses, without needing to inspect higher-layer protocols such as IP, enables switches to operate at the data link layer (Layer 2) of the OSI model, where decisions are made quickly and efficiently.

Other options, such as relying on IP addresses or DNS configuration, are more relevant to routers that operate at the network layer, and measuring bandwidth usage is a function of network monitoring rather than data forwarding. Therefore, using MAC addresses is essential for the operation of a network switch.