How Networks Work
Understand how computers communicate with each other and how data travels across local networks and the internet.
18 lessons
What Is a Network?
A network connects devices so they can exchange data, forming the foundation of all digital communication.
Local Networks vs the Internet
Local networks connect nearby devices privately, while the internet links millions of networks globally.
Routers, Switches, and Access Points
Network hardware serves distinct roles: routers direct traffic between networks, switches connect local devices, and access points provide wireless connectivity.
Physical Connections: Ethernet, Wi-Fi, and More
Data needs a physical path to travel. Different connection types offer tradeoffs between speed, reliability, and convenience.
What Is an IP Address?
Every device on a network needs an address so data knows where to go. IP addresses are the digital equivalent of home addresses.
Private and Public IP Addresses
Your home network uses private addresses internally, while sharing a single public address with the outside world.
What Is a Port?
Ports are like numbered doorways on a device, letting multiple applications communicate over the network simultaneously.
What Is a Packet?
Networks break data into small chunks called packets, making transmission more reliable and efficient.
Bandwidth and Latency
Bandwidth measures how much data can flow at once, while latency measures how long it takes to arrive. Both affect your network experience.
How IP Routing Works
Routers make hop-by-hop decisions to move packets across networks, without any single device knowing the complete path.
TCP vs UDP
TCP guarantees reliable, ordered delivery. UDP prioritizes speed over guarantees. Different applications need different tradeoffs.
Application Protocols: HTTP, HTTPS, SSH, FTP
Application protocols define how programs communicate over networks. Different protocols serve different purposes.
What Is NAT?
Network Address Translation lets multiple devices share one public IP address, making home and office networks possible.
What Is a Subnet?
Subnets divide large networks into smaller, organized groups — like neighborhoods within a city.
What Is a Firewall?
A firewall acts as a security guard for your network, controlling which traffic gets in and out.
What Do Internet Providers Do?
Internet Service Providers build and maintain the infrastructure that connects your home to the global internet.
How Network Layers Work Together
Networks use layers like floors in a building — each handles specific tasks, and they stack together to deliver your data.
How Layers Help Troubleshooting
When something breaks, checking each network layer systematically helps you find the problem faster.
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