How the Internet Works
A detailed look at internet protocols, data transmission, and network communication.
Table of contents
- The Internet: A Network of Networks
- Core Internet Infrastructure
- How Data Packets Work
- Internet Protocols
- Real-World Example: Loading a Webpage
- Hands-On Demonstration
- Network Troubleshooting
- Next Steps
- Additional Resources
The Internet: A Network of Networks
The internet is built on a hierarchical structure of networks:
- Local Networks (your home/office)
- Regional Networks (your ISP)
- National/International Networks (internet backbone)
- Tier 1 ISPs (Core Internet Infrastructure)
đź“ť Did You Know?
The internet was originally developed by DARPA (Defense Advanced Research Projects Agency) as a way to maintain communication in case of a nuclear attack.
Core Internet Infrastructure
ISP Tiers
- Tier 1 ISPs
- Form the backbone of the internet
- Direct connections to other Tier 1 providers
- Global network coverage
- Tier 2 ISPs
- Regional and national providers
- Connect to Tier 1 networks
- Serve smaller ISPs and businesses
- Tier 3 ISPs
- Local service providers
- Connect end users to the internet
- Purchase transit from larger ISPs
How Data Packets Work
When you send or receive information over the internet, it’s broken down into small pieces called packets:
- Breaking Down Data
- Large files are split into smaller packets
- Each packet contains:
- Source address
- Destination address
- Packet number
- Actual data
- Packet Routing
- Packets may take different paths
- They’re reassembled at the destination
- If a packet is lost, only that piece needs to be resent
Internet Protocols
TCP/IP (Transmission Control Protocol/Internet Protocol)
The fundamental protocol of the internet:
- TCP breaks data into packets and reassembles them
- IP handles addressing and routing
- Ensures reliable data delivery
- Manages network congestion
HTTP/HTTPS (HyperText Transfer Protocol)
Used for web browsing:
- HTTP: Basic web communication
- HTTPS: Secured, encrypted version
- TLS encryption for data protection
- Certificate validation for security
DHCP (Dynamic Host Configuration Protocol)
Automatic network configuration:
- IP address assignment
- Subnet mask configuration
- Default gateway setup
- DNS server information
DNS (Domain Name System)
The internet’s address book:
- Converts domain names to IP addresses
- Hierarchical naming system
- Distributed database
- Caching for performance
âť— Security Note
Always look for HTTPS when sharing sensitive information online. The 'S' means the connection is encrypted.
Real-World Example: Loading a Webpage
When you visit a website, here’s what happens:
- DNS Lookup
- Convert domain name to IP address
- Find the server’s location
- Connection Establishment
- Your device connects to the server
- Handshake process occurs
- Data Transfer
- Request webpage content
- Server sends back files
- Browser renders the page
Hands-On Demonstration
Try these commands to see the internet in action:
# See the path to a website
traceroute google.com
# View DNS information
nslookup google.com
# Check connection status
ping google.com
đź’ˇ Practice Exercise
Try these commands with different websites and compare the results. What differences do you notice in response times and number of hops?
Network Troubleshooting
Common issues and how to diagnose them:
- Can’t Connect to Internet
- Check physical connections
- Verify IP address assignment
- Test DNS resolution
- Slow Connection
- Check network usage
- Test bandwidth
- Monitor packet loss
- Website Not Loading
- Verify DNS resolution
- Check server status
- Clear browser cache
Next Steps
Continue to the Networking section to learn about DNS and DHCP - crucial systems that make the internet work smoothly.
Additional Resources
- Network troubleshooting guide
- Common networking commands
- Command Cheatsheet