You click a link, and a webpage from Japan appears on your screen in less than a second. You send an email to Australia, and it arrives instantly. You video chat with someone in Europe with barely any delay. But how does this actually work? How does information travel across the world so quickly?
Let's explain the internet in the simplest way possible, like you're learning about it for the very first time.
What IS the Internet?
The internet is a giant network of computers all connected together worldwide. Think of it as the world's largest spider web, except instead of connecting branches, it connects computers.
Simple analogy: Imagine a massive road system connecting every house in the world. You can drive from your house to anyone else's house by following the roads. The internet is like that, but instead of cars traveling on roads, it's information traveling on cables.
Important to understand: The internet is NOT the same as the World Wide Web (websites). The internet is the highway system, and websites are destinations you can visit on that highway.
The Physical Internet: It's Actually Made of Cables!
Here's something that surprises many people: The internet is mostly physical cables buried underground and underwater.
The Cables Under the Ocean
Undersea cables are thick cables lying on the ocean floor, connecting continents.
What they look like:
- About as thick as a garden hose
- Contains fiber optic strands (explained below)
- Heavily armored to protect from sharks (yes, really!) and ship anchors
- Hundreds of them crisscross the oceans
Where they go:
- From New York to London
- From California to Japan
- From Australia to Singapore
- Connecting every continent except Antarctica
Fun fact: When you watch a YouTube video from another continent, the data literally travels through cables on the ocean floor! It's not floating through space (well, mostly - satellites exist but handle only a small percentage).
Fiber Optic Cables: Light-Speed Information
Fiber optic cables are special cables that use pulses of light to carry information. This is what most long-distance internet uses.
How it works:
- Information is converted to flashes of light
- Light pulses travel through ultra-pure glass fiber
- Light bounces down the fiber (like water through a hose)
- On the other end, light is converted back to information
Why use light?
- Light travels at 186,000 miles per second!
- Can carry HUGE amounts of data
- Doesn't degrade over long distances
- Not affected by electrical interference
Think of it like: Morse code, but with light instead of sound, and billions of times faster.
Regular Copper Cables
Copper cables (like traditional phone lines or coaxial cable for cable TV) also carry internet, but they're slower and used for shorter distances.
How they work:
- Electrical signals travel through copper wire
- Slower than fiber optics
- Used for "last mile" connections (from the street to your house)
DSL internet and cable internet both use copper cables for the connection from the street to your home.
How Information Travels: The Journey of a Click
Let's follow what happens when you click a link to watch a YouTube video. We'll trace the entire journey!
Step 1: You Click
You're at home in New York, and you click on a cat video. That cat video file is stored on YouTube's servers in California (a server is just a powerful computer that stores files).
What needs to happen: Get the video file from California to your computer in New York.
Step 2: Your Computer Sends a Request
Your computer says: "I want the file located at youtube.com/watch?v=catvideoXYZ"
This request is broken into tiny pieces called "packets."
Think of it like this:
- Instead of sending one big envelope, you send 1,000 small postcards
- Each postcard has: A piece of the message, your return address, and the destination address
- They might travel different routes
- They're reassembled at the destination
Why use packets?
- Easier to route around problems
- Can travel different paths simultaneously
- If one gets lost, just resend that one packet (not the whole message)
Step 3: Through Your Home Network
First stop: Your router (that box with blinking lights).
Your router's job:
- Receives your request
- Adds its address to the packet
- Sends it to your Internet Service Provider (ISP)
Your ISP is the company you pay for internet (Comcast, AT&T, Verizon, etc.).
Step 4: Into the ISP's Network
Your request travels through cables to your ISP's local facility.
The ISP says: "Where does this need to go? Oh, YouTube in California!"
The ISP forwards your request through their network, which connects to the larger internet.
Step 5: Across the Country
Your packets travel through multiple stops:
- Your ISP's local router in your city
- Regional backbone network (major internet highways)
- Cross-country fiber optic cables (buried alongside highways or railroads)
- Different routers along the way, each deciding the next best hop
- Finally to California where YouTube's servers are
Important: Your packets might take different routes! It's like some postcards taking I-95 while others take Route 1. They all get there, just via different paths.
How fast? This entire journey takes about 50-100 milliseconds (less than a blink!).
Step 6: YouTube's Servers Respond
YouTube's servers receive your request:
- YouTube's server reads: "Send catvideoXYZ to IP address 123.456.78.90"
- Server finds the video file on its hard drives
- Breaks video into packets (thousands of them)
- Sends packets back to you via the internet
Step 7: The Return Journey
The video packets travel back:
- From California to regional networks
- Across the country (possibly different route than your request)
- To your ISP
- Through your ISP's network
- To your router
- To your computer
Step 8: Your Computer Reassembles Everything
Your computer:
- Receives all the packets (they might arrive out of order!)
- Checks each packet for errors
- Puts them in the right order
- Assembles them back into the video file
- Starts playing the video!
All of this happens in about 1-2 seconds. That's why the video starts playing almost instantly!
IP Addresses: The Internet's Mailing Addresses
For information to travel to the right place, every device on the internet needs an address. These are called IP addresses.
What an IP Address Looks Like
IPv4 (most common):
192.168.1.1
Four numbers separated by periods, each number between 0 and 255.
IPv6 (newer, because we're running out of IPv4 addresses):
2001:0db8:85a3:0000:0000:8a2e:0370:7334
Longer and more complex, but allows many more addresses.
How IP Addresses Work
Think of it like a postal address:
- Street address: 123 Main Street
- City: Springfieldtown
- State: New York
- Zip: 12345
IP address works similarly:
- 192 = Region (like state)
- 168 = Sub-region (like city)
- 1 = Local network (like street)
- 1 = Specific device (like house number)
When you send data:
- Source IP: Your computer's address
- Destination IP: YouTube's server address
- Routers use these addresses to forward packets to the right place
Your IP Address vs Website Addresses
You type: youtube.com
Your computer uses: 172.217.14.206 (YouTube's actual IP address)
Why the difference?
IP addresses are hard to remember. Who wants to type 172.217.14.206 when you could type youtube.com?
DNS (Domain Name System) translates friendly names to IP addresses. Think of it as the internet's phone book.
How it works:
- You type
youtube.com - Your computer asks a DNS server: "What's the IP address for youtube.com?"
- DNS server responds: "It's 172.217.14.206"
- Your computer uses that IP address to connect
This happens automatically in a fraction of a second!
Routers: The Traffic Directors of the Internet
Routers are devices that forward packets between networks. They're the traffic cops and postal workers of the internet combined.
What Routers Do
When a router receives a packet:
- Reads the destination IP address
- Checks its routing table (a list of known routes)
- Decides the next best hop
- Forwards the packet to the next router
- Repeats until packet reaches destination
Think of it like: Asking for directions. Each router knows the next step toward your destination, even if it doesn't know the complete route.
Why Multiple Hops?
Your data doesn't go directly from your computer to YouTube. It hops through 10-20 routers!
Why?
- Redundancy: If one path is down, use another
- Load balancing: Distribute traffic across multiple paths
- Efficiency: Each router only needs to know nearby routes, not every route in the world
You can see this yourself!
On Windows, open Command Prompt and type:
tracert youtube.com
On Mac/Linux, open Terminal and type:
traceroute youtube.com
You'll see every hop your data takes to reach YouTube!
How International Connections Work
When you visit a website in Japan, your data crosses the Pacific Ocean. Here's how:
The Path from New York to Tokyo
Simplified route:
- Your computer (New York)
- Your home router
- Your ISP's local network (New York)
- ISP's regional backbone (East Coast)
- Major internet exchange point (like New York IXP)
- Undersea cable landing station (New Jersey coast)
- Undersea fiber optic cable (across Pacific Ocean)
- Cable landing station (Japan coast)
- Japanese ISP's network
- Japanese website's servers (Tokyo)
The Undersea Cable Journey
Your data in the Pacific:
- Enters the ocean at a beach landing station
- Travels through cable on the ocean floor
- Crosses 6,000 miles of ocean
- Emerges at a beach in Japan
How long does this take? Light travels through fiber optic cable at about 124,000 miles per second (slightly slower than light in air).
Math:
- Distance: 6,000 miles
- Speed: 124,000 miles/second
- Time: About 0.05 seconds (50 milliseconds)
Add routing and processing time, and New York to Tokyo takes about 150-200 milliseconds total!
Ping: Measuring Connection Speed
"Ping" measures how long a round trip takes.
When you ping a server:
- Send a tiny packet
- Server immediately sends it back
- Measure total time
Typical ping times:
- Same city: 1-20ms
- Same country: 20-80ms
- Different continent: 100-300ms
- Satellite internet: 500-700ms (very far to travel!)
In gaming: Low ping is better. 20ms feels instant, 200ms feels laggy.
The Internet's Infrastructure
The internet doesn't belong to one company or government. It's a collaborative network of networks.
Internet Exchange Points (IXPs)
IXPs are buildings where different networks connect to each other.
What happens at an IXP:
- AT&T's network connects to Verizon's network
- Google's network connects to Amazon's network
- International networks connect to US networks
- Data gets exchanged without traveling extra distance
Think of it as: A train station where different rail lines meet, allowing passengers to transfer between lines.
Major IXPs:
- DE-CIX (Frankfurt, Germany) - One of the largest
- AMS-IX (Amsterdam, Netherlands)
- LINX (London, UK)
- Equinix IXPs (worldwide)
Tier 1 Networks
Tier 1 networks are the major internet backbones that connect continents.
Who they are:
- AT&T
- Verizon
- Level 3 (now Lumen)
- NTT
- Telia
- Others
What makes them Tier 1:
- They own undersea cables
- They connect to each other without paying (called "peering")
- They form the backbone of the internet
Your ISP (like Comcast) pays Tier 1 networks to access this backbone.
Content Delivery Networks (CDNs)
CDNs cache (store copies of) popular content closer to you.
Example: Netflix
Instead of streaming from one server in California:
- Netflix has servers all over the world
- Popular shows are copied to servers near you
- When you watch, it streams from the nearby server
- Faster, less strain on international cables
Other big CDNs:
- Cloudflare
- Akamai
- Amazon CloudFront
- Google Cloud CDN
This is why popular websites load fast - their content is already nearby!
How WiFi Fits In
WiFi is how you connect to the internet wirelessly at home or in coffee shops.
The chain:
- Your device connects via WiFi to...
- Your WiFi router which connects via cable to...
- Your modem which connects via cable to...
- Your ISP which connects to...
- The internet
WiFi is just the last wireless hop. Everything after your router is wired (cables)!
Common confusion:
- WiFi ≠ Internet
- WiFi is the wireless connection to your router
- Internet is the global network your router connects to
Example: You can have internet without WiFi (ethernet cable), and WiFi without internet (router not connected).
How Mobile Data Fits In
Mobile data (4G, 5G) also connects you to the internet.
The chain:
- Your phone connects wirelessly to...
- Cell tower which connects via cable to...
- Your carrier's network (AT&T, Verizon, etc.) which connects to...
- The internet
Same internet, different on-ramp!
Whether you use WiFi or mobile data, you're accessing the same internet. Just different ways to connect to it.
Internet Speed: What Determines It?
Several factors affect how fast your internet feels:
1. Your Internet Plan
Your ISP sells different speeds:
- 25 Mbps (basic)
- 100 Mbps (standard)
- 500 Mbps (fast)
- 1 Gbps (gigabit - very fast!)
Mbps = Megabits per second (how much data per second)
More Mbps = Can download more data simultaneously = Faster downloads and streaming
2. Distance to Server
Closer = Faster
- Server in your city: Very fast
- Server across the country: Fast
- Server on another continent: Slower
This is why some websites load faster than others - their servers are physically closer to you!
3. Network Congestion
More people using the network = slower for everyone
- 3 PM on a Wednesday: Fast (people at work/school)
- 8 PM on a Saturday: Slower (everyone streaming Netflix)
Like traffic on a highway - rush hour is slower than midnight.
4. Your Equipment
- Old router: Bottleneck
- Old computer: Slower processing
- WiFi vs Ethernet cable: Cable is faster and more reliable
5. The Server's Speed
Even with fast internet, if YouTube's server is overloaded, the video will load slowly. Not your fault - it's their bottleneck!
Security: How the Internet Stays (Mostly) Safe
HTTPS: Encrypted Connections
When you see https:// in the URL (with a padlock icon), your connection is encrypted.
What this means:
- Your data is scrambled during transmission
- Only you and the server can read it
- No one in the middle can spy on you
Example:
- Banking websites: Always HTTPS
- Online shopping: Should be HTTPS
- Facebook, Gmail, etc.: HTTPS
Never enter passwords or credit card info on a site without HTTPS!
How Encryption Works (Simple Version)
Without encryption (HTTP):
- Like sending a postcard
- Anyone handling it can read it
- Bad for sensitive data!
With encryption (HTTPS):
- Like sending a locked box
- Only you and the recipient have the key
- Even if intercepted, can't be read
Public WiFi warning: Even with HTTPS, avoid doing banking on public WiFi. Use your phone's mobile data for sensitive stuff when in public.
Common Questions from Beginners
"Who owns the internet?"
No one! The internet is a collaborative network. Different companies own different parts:
- Your ISP owns cables to your house
- Tier 1 networks own backbone cables
- Companies own undersea cables
- Google owns Google's servers
- You own your router
Think of it like: The highway system. Government owns highways, companies own trucks, you own your car. No one owns all of it.
"Can the internet run out of space?"
The internet can't "fill up" like a hard drive. It's a network, not a storage device.
What CAN run out:
- IP addresses (we're switching to IPv6 to solve this)
- Bandwidth (too much traffic can slow things down)
- Server storage (websites can run out of space)
But the internet itself? Infinite capacity. We just keep adding more cables and servers.
"What happens if an undersea cable breaks?"
They break more often than you'd think!
Causes:
- Ship anchors
- Earthquakes
- Sharks biting them (seriously!)
What happens:
- Traffic automatically reroutes through other cables
- You might notice slower international connections
- Usually fixed within days (special ships repair them)
There are so many cables that one breaking rarely causes major problems.
"Is satellite internet part of this?"
Yes, but it's a small part.
Traditional undersea cables carry 99% of international internet traffic.
Satellite internet:
- Used in remote areas without cables
- Higher latency (data has to go to space and back!)
- Starlink and similar are improving this
For most people: Cable/fiber internet is faster and more reliable than satellite.
"What's the difference between the internet and WiFi?"
Internet: The global network of networks WiFi: The wireless connection from your device to your router
Analogy:
- Internet = The highway system
- WiFi = Your driveway to the street
You can have internet without WiFi (ethernet cable), and WiFi without internet (router not connected).
Summary: How the Internet Works
The simple version:
- Physical infrastructure: Cables (undersea, underground, in your walls) connect the world
- Your request: You click a link, computer breaks request into packets
- Through your network: Packets go through your router → ISP → internet backbone
- Across the world: Packets hop through routers, potentially crossing oceans via undersea cables
- To the server: Packets reach the website's server (maybe in another country)
- Response: Server sends back packets with the webpage/video/data
- Back to you: Packets travel back through the internet, possibly taking different routes
- Reassembly: Your computer puts packets back together and displays the result
All of this happens in less than a second!
The key insight: The internet is mostly physical - cables in the ocean, buried underground, and in your walls. It's not magic floating through the air (except your WiFi, which is just the last wireless hop).
The beautiful part: It all works together automatically. Routers figure out the best paths. Packets find their way even if some routes are blocked. The internet routes around damage. It's a resilient, self-healing system.
You now understand how the internet works! Next time you watch a video from Japan or text someone in Europe, you'll know your data is traveling through cables on the ocean floor, hopping through routers worldwide, all in fractions of a second.
Related guides you might enjoy:
- How WiFi Works: Wireless Internet Explained
- What is a VPN and Why Would You Use One?
- How Email Actually Works (It's More Complex Than You Think!)
- The History of the Internet: From 1960s to Today