naveenopslearn
Search
Course outline
  1. 01How a computer works
    1. 1.1What is a computer?(completed)
    2. 1.2The CPU: the brain(completed)
    3. 1.3Memory: RAM vs storage(completed)
    4. 1.4How the CPU and memory work together(completed)
    5. 1.5What happens when you turn on a computer(completed)
  2. 02How the Internet works
    1. 2.1What is the Internet?(completed)
    2. 2.2Addresses and names: IP and DNS(completed)
    3. 2.3Packets: how information travels(completed)
    4. 2.4Client and server: opening a website(completed)
    5. 2.5Inside a busy server(completed)
    6. 2.6Why this matters for AI(completed)
  3. 03Introducing the GPU
    1. 3.1What is a GPU?(completed)
    2. 3.2CPU vs GPU(completed)
    3. 3.3The GPU's own memory: VRAM(completed)
    4. 3.4How the CPU and GPU work together(completed)
    5. 3.5Why GPUs suit AI(completed)
  4. 04Tensors and models
    1. 4.1What is a tensor?soon
    2. 4.2What is an AI model?soon
    3. 4.3Training vs inferencesoon
  5. 05Splitting work across GPUs
    1. 5.1Why split work across GPUs?soon
    2. 5.2Data parallelismsoon
    3. 5.3Tensor parallelismsoon
    4. 5.4Pipeline parallelismsoon
    5. 5.5Expert parallelismsoon
    6. 5.6Which to use whensoon
  6. 06Serving LLMs with vLLM
    1. 6.1What is LLM serving?soon
    2. 6.2Meet vLLMsoon
    3. 6.3Serving a model with vLLMsoon

Lesson 2.1

What is the Internet?

A network of networks: many smaller networks agreeing to pass messages along.

beginner 3 min readChecked

In one line

The Internet is a network of networks: millions of smaller networks, joined together so that any computer can send a message to any other.

Real-life analogy

In Module 1, our restaurant was one building. Now imagine every restaurant in the world, and every home and office, connected by roads.

Your street connects to a bigger road. That road joins a motorway. Motorways link cities and countries. No one owns all the roads, but because they connect, a delivery van can get from your kitchen to almost any address on Earth.

The Internet is those roads, and the networks are the neighbourhoods they join.

Where the comparison stops working: a van carries the whole parcel in one trip. On the Internet, a message is cut into many small pieces that can each take a different road. We will see that in lesson 2.3.

Diagram

Home networklaptop, phone, TVOffice networkPCs, printersSchool networktablets, PCsrouterrouterrouterInternet provider AInternet provider BInternet provider CThe Internet: many networks, linked by providers that agree to pass messages along.
The Internet is many separate networks, joined together by providers that pass messages to each other.

Step by step

You use the Internet every day. But have you ever wondered what it actually is? Is it a place? A cable? A company?

Step 1: a network

A network is simply two or more computers connected so they can send messages to each other.

Your home Wi-Fi is a small network. Your laptop, phone and smart TV are all on it.

Step 2: connecting networks with routers

On its own, your home network can only talk to devices inside your home. To reach the outside world, it needs a router.

A router is a device that connects one network to other networks. Its job is to pass each message one step closer to where it needs to go. That little box from your Internet provider is a router (often with Wi-Fi built in).

Step 3: Internet providers

Your router connects to your Internet provider (also called an ISP, Internet service provider). Your provider runs its own big network, full of routers.

Here is the key part: Internet providers connect to each other. Your provider is linked to other providers, and those are linked to more providers, all over the world.

Step 4: a network of networks

Put it all together:

  • your home network connects to your provider,
  • your provider connects to other providers,
  • those providers connect to other homes, offices, schools and data centres.

That giant web of connected networks is the Internet. There is no single “Internet computer” in the middle. It works because all these networks agree on the same rules for passing messages along.

The Internet is not the web

People often use “Internet” and “web” as if they mean the same thing. They do not.

  • The Internet is the roads: the connected networks.
  • The web (websites you open in a browser) is one service that travels on those roads.

Email, video calls and online games are other services that use the same roads.

Key takeaways

  • A network is a group of connected computers.
  • Routers connect networks and pass messages one step closer to where they are going.
  • Internet providers link their networks to each other, all around the world.
  • The Internet is that network of networks. The web is just one service that runs on it.

Recap: neighbourhoods (networks) joined by roads (providers and routers) so that a message can travel from any address to any other.

Now you understand what the Internet really is. Next: how does a message know where to go? We will look at addresses and names.

Quick check

Pick an answer, then press Check answer. Nothing is recorded.

  1. Which description of the Internet is most accurate?
  2. What does a router do?
  3. Is email part of the web?

Sources

This lesson was checked against these pages.

  1. How does the Internet work? · MDN Web Docs
  2. How the web works · MDN Web Docs