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The Complete Handbook of Hubs & Switches
A Professional's Guide to Network Infrastructure from Physical Layer to Deployment
by Alumigogo Books
Chapter 1: Understanding Hubs & Switches
A network hub and a network switch are both devices that sit in a rack or on a shelf and connect computers, servers, and other networked equipment together. If you walk into a small office, a factory floor, or a data center, you will see one or both of them. Yet despite looking similar—both are typically rectangular boxes with ports where you plug in cables—they work in fundamentally different ways. That difference determines how many devices you can reliably connect, how fast data moves, whether collisions slow everything down, and how much you pay. Understanding this difference is the foundation for every decision you will make about network infrastructure.
What a Hub Does
A hub is the simpler device. It has multiple ports, and when it receives a data frame (a chunk of data traveling over the network) on one port, it sends that frame out to all the other ports. It does not look at addresses, does not store information about which device is connected where, and does not make any decision about where the frame should go. It is essentially a repeater with multiple ports—it takes an electrical signal in on one port, amplifies it slightly, and broadcasts it out every other port simultaneously.
This broadcast approach creates a problem when two or more devices connected to the hub try to send data at the same time. Both signals collide on the cable. The collision is detected by the devices (using a