A layer 2 switch determines which port to send a packet through by examining what?

A layer 2 switch identifies which port to send a packet through by examining the MAC address of the destination. This is because switches operate at the data link layer of the OSI model, where MAC addresses function as unique hardware identifiers for devices on a network. When a switch receives a frame, it reads the destination MAC address and consults its MAC address table, which contains mappings of MAC addresses to specific ports.

If the destination MAC address is found in the table, the switch forwards the frame out through the corresponding port. If it is not in the table, the switch will broadcast the frame to all ports except the one it received it on, ensuring that the destination device can respond. This process optimizes network traffic and minimizes unnecessary data transmission, highlighting the importance of MAC addresses in Layer 2 switching.