What is the primary function of a network switch?

What is the primary function of a network switch?

• A. To route packets between different networks using IP addresses
• B. To assign IP addresses to devices via DHCP
• C. To filter traffic using IP addresses
• D. To connect multiple devices and forward frames based on MAC addresses

Answer: (D)

A network switch’s main job is to connect multiple devices within the same local network and forward frames based on MAC addresses. It operates at the data link layer and learns where each device is by reading the source MAC address on incoming frames, building a MAC address table that maps addresses to specific ports. When a frame has a destination MAC that the switch knows, it sends the frame only out the port associated with that MAC, keeping traffic local to the intended recipient. If the destination MAC isn’t in the table yet, the switch floods the frame to all ports except the one it came from, until it learns where that device is. This targeted forwarding reduces collisions and limits unnecessary traffic. By contrast, routing between different networks uses IP addresses (a router’s job), DHCP assigns IPs, and IP-based filtering is typically done with routers or firewalls, not primarily by switches.

A network switch’s main job is to connect multiple devices within the same local network and forward frames based on MAC addresses. It operates at the data link layer and learns where each device is by reading the source MAC address on incoming frames, building a MAC address table that maps addresses to specific ports. When a frame has a destination MAC that the switch knows, it sends the frame only out the port associated with that MAC, keeping traffic local to the intended recipient. If the destination MAC isn’t in the table yet, the switch floods the frame to all ports except the one it came from, until it learns where that device is. This targeted forwarding reduces collisions and limits unnecessary traffic. By contrast, routing between different networks uses IP addresses (a router’s job), DHCP assigns IPs, and IP-based filtering is typically done with routers or firewalls, not primarily by switches.