Lesson 9: Basic Network Devices: Hubs (Historical Context)

To understand modern devices, we must first look at their predecessor: the Hub.

What is a Hub?

A Hub is a simple, multi-port connectivity device used to connect multiple segments of a network. It operates at the most basic level of networking—Layer 1, the Physical Layer.

How a Hub Works (The Dumb Device)

When a hub receives a data signal (bits) on one port, it performs a simple action: it regenerates the signal and broadcasts it out to every other connected port.

• The hub does not inspect the data address; it blindly forwards the signal everywhere.
• Only the intended recipient device will recognize the signal and process it; all other devices ignore it.

The Problem: Collision Domains

Because the hub broadcasts every transmission, only one device can transmit at a time. If two devices transmit simultaneously, their electrical signals collide, corrupting the data.

• A network connected by a hub is considered a single, large collision domain.
• This inefficiency dramatically lowers network performance, especially under heavy traffic.

Modern Usage: Hubs are considered obsolete and are almost never used in modern networks. They have been replaced entirely by smart devices called Switches (which we cover in the next lesson).