Open Learning Library

A library for learning by doing.

Practical, interactive courses to help you build real skills in technology, the trades, and business. Learn in your browser, or download a complete course as a single HTML file to keep and use offline.

Explore all courses How offline learning works

Free courses · No account required · Downloadable HTML files

/networking/

Practical Networking

24 lessons · ~10 hours

Course progress

1 · How Networks Talk: Models & the OSI Model

2 · Network Devices & Cabling

3 · Signals, Media & Standards

4 · IPv4 Addressing

5 · Subnetting IPv4

6 · IPv6 Essentials

Lesson 1 of 24

How Networks Talk: Models & the OSI Model

25 MIN2 HANDS-ON LABS3 SELF-CHECKS

Layer 1 Physical is cables, connectors, and signals: if the link light is dark, the problem lives here. Layer 2 Data Link is MAC addresses, Ethernet frames, and switches. Layer 3 Network is IP addresses and routing…

Subnet calculator

192.168.10.0 /24Calculate

Network 192.168.10.0
Broadcast 192.168.10.255
Usable hosts 254

Inside Practical Networking: a lesson page, with the course’s built-in subnet calculator below the text.

The Course Library

Find your next skill.

Explore practical, interactive courses in technology, the trades, and business. Open a course to start learning, or download it to keep.

Learning, on your terms

Learn your way. Keep your progress.

Every course is a complete, interactive HTML file. Start in your browser or download a copy for offline study.

01 / START

Open and learn

Open any free course in your browser and work through its lessons, labs, quizzes, and practice exam.

02 / KEEP

Take it offline

Download the complete course as one HTML file. Open the downloaded file in a compatible browser to study without an internet connection.

03 / CONTINUE

Pick up where you left off

Your progress is saved in the browser as you study. Saved progress stays with that browser storage; it does not automatically sync between devices or between online and downloaded copies.