What Is a Network Switch?
a Network Switch — a Layer 2 device that forwards frames between devices on the same network using MAC addresses — the device your PCs, printers and access points plug into.
How it works
A switch learns the MAC address of each connected device and builds a table mapping addresses to ports. When a frame arrives, it forwards it only out the port where the destination lives — unlike a hub, which floods everything. Each port is its own collision domain.
Why it matters
Switches are the workhorses of every LAN, and most CCNA switching content — VLANs, trunking, spanning tree — lives here. A Layer 3 switch adds routing between VLANs. Compare with a router and hub, and see VLANs.
Frequently asked questions
What does a network switch do?
It forwards frames between devices on the same network using MAC addresses, sending each frame only to the correct port rather than flooding all ports.
What is the difference between a switch and a hub?
A switch learns MAC addresses and forwards intelligently, giving each port its own collision domain; a hub blindly repeats to all ports, sharing one collision domain.
What is a Layer 3 switch?
A switch that can also route between VLANs at hardware speed using SVIs, combining switching and routing in one device.
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