5.1 How Wi-Fi Works
Every day, many people connect a phone, laptop, tablet, smart television, gaming console, printer, or other device to Wi-Fi and immediately begin browsing websites, streaming videos, sending messages, or using online services.
Because Wi-Fi is so common, many people think of it as the Internet itself. However, Wi-Fi and the Internet are not the same thing.
Wi-Fi is a method of connecting devices to a local network using wireless signals.
The Internet is the larger global network that those devices may access through that local network.
Wi-Fi is how your device talks to your local network.
The Internet is how that network talks to the rest of the world.
What Is Wi-Fi?
Wi-Fi is a wireless networking technology that allows devices to communicate without using physical network cables. Instead of sending information through Ethernet cables, Wi-Fi uses radio waves.
Radio waves are a form of electromagnetic energy that can carry information through the air. Many technologies use radio waves, including:
- Radio broadcasts
- Television broadcasts
- Cellular networks
- Bluetooth devices
- Satellite communications
- Wi-Fi networks
Wi-Fi is just one of many technologies that use radio waves to communicate. It was specifically designed to connect computers and other devices to local networks without cables.
What Does Wi-Fi Connect To?
When a device joins a Wi-Fi network, it usually connects to a device called a wireless access point (WAP).
In homes and small businesses, the wireless access point is often built into the same device as the router. This is why people commonly refer to the device as a “Wi-Fi router.”
The router performs several jobs at once:
- Creates the Wi-Fi network
- Connects local devices together
- Assigns local IP addresses
- Connects the local network to the Internet through an Internet Service Provider (ISP)
A simplified example looks like this:
Phone
↓
Wi-Fi
↓
Router
↓
ISP
↓
Internet
Without the router and ISP connection, Wi-Fi would still allow local devices to communicate, but those devices would not necessarily have Internet access. This is why it is possible for Wi-Fi to be working while the Internet is down.
How Devices Join a Wi-Fi Network
When a device searches for Wi-Fi, it listens for nearby wireless networks. These networks usually appear as a list of names such as:
- HomeWiFi
- CoffeeShopGuest
- AirportFreeWiFi
The name of a Wi-Fi network is called an SSID, which stands for Service Set Identifier.
An SSID is simply the network name that devices display when searching for available Wi-Fi connections.
When a user selects a network and enters the correct password (if required), the device and router establish a wireless connection. Once connected, the device becomes part of that local network. The router can then exchange data with the device and help direct traffic toward the Internet.
Wi-Fi Uses Radio Channels
Just as many radio stations can operate in the same city, many Wi-Fi networks can operate in the same area. To reduce interference, Wi-Fi networks use different channels.
A channel is a portion of the radio spectrum used for communication.
If too many nearby networks use the same channel, performance may decrease because devices must compete for airtime. Modern Wi-Fi equipment can often choose channels automatically to reduce congestion and improve performance. This is one reason Wi-Fi speeds can vary from place to place.
Wi-Fi Frequency Bands
Modern Wi-Fi commonly operates on several frequency bands.
The most common are:
- 2.4 GHz
- 5 GHz
- 6 GHz
These frequency bands each have strengths and weaknesses.
2.4 GHz
Advantages:
- Longer range
- Better at passing through walls
Disadvantages:
- Lower speeds
- More interference from other devices
5 GHz
Advantages:
- Faster speeds
- Less interference
Disadvantages:
- Shorter range
- Reduced ability to pass through obstacles
6 GHz
Advantages:
- Very high speeds
- Less congestion
- More available channels
Disadvantages:
- Shortest range
- Requires newer devices and equipment
A useful rule of thumb is:
- Lower frequencies generally travel farther.
- Higher frequencies generally carry more data.
Why Wi-Fi Speed Changes
People often assume Internet speed depends only on their ISP plan. In reality, many factors affect Wi-Fi performance.
These factors include:
- Distance from the router
- Walls and obstacles
- Network congestion
- Signal interference
- Number of connected devices
- Router quality
- Device quality
- Frequency band being used
For example, a laptop sitting next to a router may achieve much faster speeds than a phone located several rooms away. Even though both devices are using the same Internet connection, the wireless signal conditions are different.
Wi-Fi Standards
Over time, Wi-Fi technology has improved. New generations of Wi-Fi generally provide higher speeds, better efficiency, improved reliability, and greater support for many devices. Common modern standards include:
- Wi-Fi 4 (802.11n)
- Wi-Fi 5 (802.11ac)
- Wi-Fi 6 (802.11ax)
- Wi-Fi 6E
- Wi-Fi 7
Most users do not memorize these standards. The important idea is that newer Wi-Fi generations are generally faster and better able to support large numbers of connected devices.
Wi-Fi and Security
Most Wi-Fi networks use passwords and encryption to help prevent unauthorized access.
Encryption helps protect information as it travels between devices and the wireless access point.
Modern Wi-Fi networks commonly use security standards such as WPA2 and WPA3. These technologies help make wireless communication more secure.
However, Wi-Fi security is only one layer of security. A secure Wi-Fi connection does not automatically make every website, app, or service trustworthy.
We will discuss wireless security in greater detail later in this module.
Why Wi-Fi Matters
Wi-Fi is one of the technologies that makes modern computing convenient and mobile.
Without Wi-Fi, many devices would require physical cables for network access. Homes, schools, businesses, airports, hotels, coffee shops, and public spaces would look very different.
Wi-Fi allows devices to communicate through radio waves, connect to local networks, and access Internet services without being physically attached to network cables.
For many people, Wi-Fi is the primary way they connect to the digital world.
In the next section, we will examine cellular networks and mobile data, which allow devices to remain connected even when they are far away from a Wi-Fi network.