Purpose

In this module, you will learn how computers connect to each other and share information across networks.

Most modern technology depends on networks. When you browse the internet, send email, stream video, or access cloud services, your computer is communicating with other computers through a network.

You should understand:

• what a network is

• how devices connect to networks

• the difference between local networks and the internet

• basic networking hardware and terminology

What Is a Network?

A network is a group of devices connected together so they can share information. They must have a Network Interface Card (NIC). That component can be wired or wireless. 

Devices that commonly connect to networks include:

• computers
• smartphones
• tablets
• printers
• smart TVs
• servers

Networks allow devices to communicate and exchange data.

For example, when you open a website, your computer sends a request through the network to another computer that hosts the website.

Local Networks vs The Internet

There are different types of networks depending on their size and scope.

Local Area Network (LAN)

A LAN connects devices within a small area.

Examples include:

• homes
• offices
• schools

Devices in a LAN can share files, printers, and internet access.

Wide Area Network (WAN)

A WAN connects networks across large geographic areas.

The internet is the largest WAN in the world.

It connects millions of smaller networks together.

Wired vs Wireless Networks

Computers can connect to networks in two main ways.

Wired Connections

A wired connection uses a physical cable to connect devices to the network.

The most common wired network cable is Ethernet.

Wired connections typically provide:

• faster speeds
• more stable connections
• less interference

Wired connections are commonly used in offices and data centers. It is also very common to use wired connections for special events such as conferences or other live events. This ensures that the connectivity is faster, stable, and with less interference. 

Wireless Connections

Wireless networks allow devices to connect without cables.

These networks use radio signals to transmit data.

Wireless networking is commonly called Wi-Fi.

Wireless connections are widely used in:

• homes
• coffee shops
• airports
• schools

Wireless connections typically provide:

• convenience
• mobility
• free access to the internet

When you join a public wireless connection at a coffee shop or elsewhere, your information is not as secure.

Networking Devices

Several pieces of hardware help networks function.

Modem

A modem connects a home or office network to the Internet Service Provider (ISP).

It translates signals from the internet into a format that computers can use.

Router

A router connects multiple devices to a network and directs traffic between networks.

In homes, the router usually connects the local network to the internet.

Think of the router as a doorway into a network and out of a network.

Switch

A switch connects multiple devices within a local network.

Switches allow devices on the same network to communicate efficiently.

Switches are smart and can direct specific traffic to specific devices. They build tables to keep track of this information.

IP Addresses

Every device on a network needs a unique identifier.

This identifier is called an IP address.

An IP address allows networks to identify where data should be sent.

Example of an IP address:

192.168.1.10

This number acts like a mailing address for a device on a network - just like a mailing address for your house.

How Data Moves Across Networks

When computers communicate across networks, they send information in small pieces called data packets.

Each packet contains:

• the destination address
• the sender address
• the data being transmitted

Routers and other networking devices help move these packets to the correct destination.

Important Acronyms for This Module

LAN — Local Area Network - A network that connects devices within a limited geographic area such as a home, school, or office.

WAN — Wide Area Network - A network that connects multiple smaller networks across large geographic areas.

IP — Internet Protocol - A set of rules that defines how devices communicate across networks and identifies devices using IP addresses.

MAC — Media Access Control - A unique hardware address assigned to a network interface that identifies a specific device on a network.

NIC — Network Interface Card - A hardware component that allows a computer to connect to a network.

ISP — Internet Service Provider - A company that provides access to the internet.

SSID — Service Set Identifier - The name assigned to a wireless network that users see when selecting Wi-Fi.

RF — Radio Frequency - Wireless networks transmit data using radio signals over specific frequencies.

Key Takeaways

Networks allow computers and other devices to communicate and share information.

Local networks connect devices in a small area, while the internet connects networks across the world.