What the internet actually is (network of networks) in Intro to Computing - Deep Dive

Overview - What the internet actually is (network of networks)

What is it?

The internet is a huge system that connects many smaller computer networks all over the world. It allows computers and devices to talk to each other by sending information through these networks. Think of it as a giant web made up of many smaller webs linked together. This connection lets us browse websites, send emails, watch videos, and much more.

Why it matters

Without the internet as a network of networks, computers would only be able to communicate within small groups or local areas. We wouldn't have the global access to information, communication, and services that we rely on every day. The internet makes it possible for people to connect instantly across countries and continents, powering businesses, education, and social life worldwide.

Where it fits

Before learning about the internet, you should understand basic computer networks and how devices connect locally. After this, you can explore how data travels on the internet, including protocols like TCP/IP and concepts like web servers and browsers.

Mental Model

Core Idea

The internet is a vast collection of many smaller networks connected together to share information globally.

Think of it like...

Imagine the internet as a huge system of roads connecting many towns and cities (networks). Each town has its own streets (local networks), but the highways (internet connections) link them all so people and goods (data) can travel anywhere.

┌─────────────┐       ┌─────────────┐       ┌─────────────┐
│ Local Net 1 │──────▶│ Local Net 2 │──────▶│ Local Net 3 │
└─────┬───────┘       └─────┬───────┘       └─────┬───────┘
      │                     │                     │       
      ▼                     ▼                     ▼       
  ┌─────────┐           ┌─────────┐           ┌─────────┐  
  │ Router  │◀─────────▶│ Router  │◀─────────▶│ Router  │  
  └─────────┘           └─────────┘           └─────────┘  
          ╰─────────────── Internet ───────────────╯      

Build-Up - 6 Steps

1

Foundation

Understanding Local Networks

Concept: Learn what a local network is and how devices connect within it.

A local network is a group of computers and devices connected in a small area, like a home or office. They share information directly using cables or Wi-Fi. For example, your phone and laptop connected to the same Wi-Fi are on a local network.

Result

Devices on a local network can share files, printers, and internet access easily.

Knowing local networks helps you see the building blocks that make up the larger internet.

2

Foundation

What is a Network Router?

Concept: Introduce the device that connects different networks together.

A router is like a traffic director for data. It connects local networks to other networks and decides the best path for information to travel. Without routers, networks would be isolated and unable to communicate beyond their own group.

Result

Routers enable devices in one network to send data to devices in another network.

Understanding routers shows how separate networks link to form bigger networks.

3

Intermediate

Connecting Networks to Form the Internet

🤔Before reading on: do you think the internet is one single network or many networks connected? Commit to your answer.

Concept: The internet is not one network but many networks connected through routers and other devices.

Each local network connects to other networks via routers and internet service providers (ISPs). These connections form a global web of networks. Data travels through this web by hopping from one network to another until it reaches its destination.

Result

The internet allows devices anywhere in the world to communicate by passing data through multiple networks.

Knowing the internet is a network of networks helps you understand why data can travel globally but may take different routes.

4

Intermediate

How Data Travels Across Networks

🤔Before reading on: do you think data travels in one piece or in small parts across the internet? Commit to your answer.

Concept: Data is broken into small pieces called packets that travel independently across networks.

When you send information, it is split into packets. Each packet may take a different path through the network of networks. Routers guide packets toward their destination. Once all packets arrive, they are reassembled into the original data.

Result

Data can travel efficiently and reliably even if some paths are busy or broken.

Understanding packet travel explains how the internet stays fast and reliable despite its complexity.

5

Advanced

Role of Internet Protocols

🤔Before reading on: do you think all networks speak the same language automatically? Commit to your answer.

Concept: Protocols are rules that networks follow to communicate and understand each other.

The internet uses protocols like TCP/IP to standardize how data is sent and received. TCP ensures packets arrive correctly and in order. IP handles addressing so data reaches the right device. Without these protocols, networks would not understand each other.

Result

Protocols enable seamless communication across diverse networks worldwide.

Knowing protocols reveals the hidden rules that make the internet work smoothly.

6

Expert

Internet as a Decentralized Network

🤔Before reading on: do you think the internet has a central control point? Commit to your answer.

Concept: The internet is decentralized, meaning no single entity controls it all.

The internet is designed so many independent networks connect without a central hub. This decentralization makes it robust and scalable. If one part fails, data can reroute through others. Organizations like ICANN coordinate addresses but do not control the entire internet.

Result

The internet remains reliable and grows continuously without a single point of failure.

Understanding decentralization explains why the internet is resilient and hard to shut down.

Under the Hood

The internet works by linking many independent networks using routers and standardized protocols. Data is split into packets, each carrying source and destination addresses. Routers read these addresses and forward packets along paths toward their destination. Protocols like TCP/IP ensure packets arrive intact and in order. This layered system allows diverse networks to interoperate seamlessly.

Why designed this way?

The internet was designed as a decentralized network to survive failures and grow without central control. Early designers wanted a system that could route around damage, such as during emergencies. Using protocols allowed different network types to connect, avoiding vendor lock-in and enabling global expansion.

┌───────────────┐       ┌───────────────┐       ┌───────────────┐
│ Device A      │       │ Router 1      │       │ Router 2      │
│ (Source)      │──────▶│               │──────▶│               │
└──────┬────────┘       └──────┬────────┘       └──────┬────────┘
       │                       │                       │       
       ▼                       ▼                       ▼       
┌───────────────┐       ┌───────────────┐       ┌───────────────┐
│ Packet Split  │       │ Packet Routed │       │ Packet Routed │
│ into Packets  │       │ by IP Address │       │ by IP Address │
└──────┬────────┘       └──────┬────────┘       └──────┬────────┘
       │                       │                       │       
       ▼                       ▼                       ▼       
┌───────────────┐       ┌───────────────┐       ┌───────────────┐
│ Network of    │──────▶│ Network of    │──────▶│ Device B      │
│ Networks      │       │ Networks      │       │ (Destination) │
└───────────────┘       └───────────────┘       └───────────────┘

Myth Busters - 4 Common Misconceptions

Quick: Do you think the internet is a single physical network owned by one company? Commit to yes or no.

Common Belief: The internet is one big network owned and controlled by a single company or organization.

Reality: The internet is a collection of many independent networks owned by different organizations, connected through agreed protocols.

Why it matters: Believing in a single owner can lead to misunderstandings about internet governance, censorship, and why outages happen in some places but not others.

Quick: Do you think data travels as one whole piece from sender to receiver? Commit to yes or no.

Common Belief: Data sent over the internet travels as one complete piece directly from sender to receiver.

Reality: Data is broken into small packets that travel independently and may take different routes before being reassembled.

Why it matters: Misunderstanding this can cause confusion about delays, lost data, or why some parts of a message arrive before others.

Quick: Do you think the internet has a central control point that can shut it down? Commit to yes or no.

Common Belief: There is a central control point or server that manages and can shut down the entire internet.

Reality: The internet is decentralized with no single control point; it is designed to keep working even if parts fail.

Why it matters: Thinking there is a central control can lead to false fears about internet shutdowns and misunderstandings about its resilience.

Quick: Do you think all networks connected to the internet use the same technology? Commit to yes or no.

Common Belief: All networks connected to the internet use the exact same technology and equipment.

Reality: Different networks use various technologies but communicate using common protocols to interoperate.

Why it matters: Assuming uniform technology can cause confusion when troubleshooting connectivity or understanding internet diversity.

Expert Zone

1

The internet's routing system uses dynamic path selection, meaning routes can change in real-time based on network conditions.

2

IP addresses are hierarchical and managed globally to avoid conflicts, but private networks use separate address spaces requiring translation.

3

The Domain Name System (DNS) acts like a phonebook, translating human-friendly names to IP addresses, which is critical for usability.

When NOT to use

The internet as a network of networks is not suitable for isolated or highly secure environments where external connections are restricted. In such cases, private intranets or VPNs are preferred to control access and security tightly.

Production Patterns

Large companies use multiple ISPs and redundant routers to ensure continuous internet connectivity. Content delivery networks (CDNs) place data closer to users by connecting to many networks, improving speed and reliability.

Connections

Supply Chain Networks

Both are complex systems connecting many independent entities to deliver goods or data.

Understanding how supply chains coordinate many suppliers helps grasp how the internet coordinates many networks to deliver information.

Human Nervous System

Both use decentralized networks to transmit signals efficiently across a large system.

Seeing the internet like a nervous system highlights its resilience and ability to reroute signals when parts fail.

Postal Mail System

Data packets traveling through networks are like letters sent through postal routes with addresses guiding delivery.

Knowing how mail is routed through post offices helps understand how data packets find their way across the internet.

Common Pitfalls

#1 Assuming the internet is a single network causing confusion about connectivity issues.

Wrong approach:

Trying to fix internet problems by restarting only one device without considering network-wide issues.

Correct approach:

Check multiple network points including routers, ISPs, and local networks to diagnose connectivity.

Root cause:

Misunderstanding the internet's structure leads to oversimplified troubleshooting.

#2 Believing data travels as one piece causing confusion about delays and packet loss.

Wrong approach:

Expecting instant delivery of large files without buffering or retransmission.

Correct approach:

Understand data is sent in packets and may arrive out of order or need resending.

Root cause:

Lack of knowledge about packet switching and protocols.

#3 Thinking the internet can be centrally controlled leading to unrealistic expectations about shutdowns.

Wrong approach:

Assuming turning off one server or company can disable the entire internet.

Correct approach:

Recognize the internet's decentralized design prevents single points of failure.

Root cause:

Confusing centralized services with the global internet infrastructure.

Key Takeaways

The internet is a global system made by connecting many smaller networks together.

Routers and protocols like TCP/IP allow different networks to communicate and send data reliably.

Data travels in small packets that can take different paths and are reassembled at the destination.

The internet is decentralized, making it robust and scalable without a single control point.

Understanding the internet as a network of networks helps explain its power, resilience, and complexity.