How does the Internet actually work?

In this follow up article, I will try to explain how actually the internet functions in easiest way we can understand. I will focus on topics like, how is information transported from one device to other through internet, and the steps behind it. References are taken from "https://roadmap.sh/guides/what-is-internet" and tools like ChatGPT.

Disclaimer: The concepts and examples presented in this article are intended to simplify complex technical subjects for the benefit of a general audience. While every effort has been made to provide accurate and understandable explanations, it's important to acknowledge that the workings of the internet involve intricate processes and technologies. Therefore, the explanations offered here may not encompass the entirety of the topic and may, in some cases, involve simplifications for clarity.

Information on the internet moves from one device or computer to another in the forms of bits over various mediums like ethernet cables, Fiber-Optic cables and wireless signals.

A bit has two possible states. "On or Off" or "Yes or No" which computes to "1 or 0". This is why we call it a binary code.

8 bits make 1 byte. 1024 bytes make 1 kilobyte. 1024 kilobytes is 1 megabyte. A song is encoded as around 3-4 megabytes. Every format or type of information is converted into these atomic bits of 1s and 0s, in order to transmit through the internet. These bits are are not the data that are physically transported, however, electric pulses, light waves and radio waves are used to represent the bit of the information sent which are read, collected and processed by the receiver.

Ethernet cables which are made up of copper wires, transmit data as electrical signals. In this case, electrical voltage represents the 0s and 1s. For example, a higher voltage might stand for a 1, while a lower voltage could indicate a 0.

Fibre-Optic cables are made up of glass threads that carry light signals. Data is converted into pulses of light, where "on" (1) represents a pulse, and "off" (0) means no pulse.

These pulses travel through the cable at the speed of light, making it one of the fastest transmission methods. Massive, specialised undersea cables that lay on the ocean floor and connect continents are vital for global internet connectivity. They often use fiber-optic technology for data transmission. Fiber-Optic cables are the preferred choice for undersea communication due to their high bandwidth and reliability. The "hello" message you sent from Australia, to your mate in USA, travels through Pacific Ocean. In general, for typical internet communication, messages can travel at the speed of light through fiber-optic cables. The speed of light to fly around the earth is just 0.1338763440860215 seconds. So we can imagine how fast it can be.

Wireless communication uses radio waves to transmit data. Binary code (0s and 1s) is represented by different frequencies or amplitudes of radio waves. Our Wi-Fi router and mobile phone use wireless technology to send and receive data without physical cables.

Similarly, satellites are also used to transmit data over long distances. Satellite TV or GPS are commonly used for global communications. Bluetooth is also a wireless technology used for connecting devices like headphones and smartphones, where audio data is transmitted as radio waves. Infrared or IR is commonly used for short-range communication, such as TV remote controls where binary data is sent as pulses of infrared light.

Steps of transmission:

1. Data Creation: The process begins when someone creates data, such as writing an email or text messages or posting a photo on social media in their device. This data could be text, images, videos, or any digital information.
2. Data Segmentation: Before data can travel across the internet, it needs to be split, organised and packaged into small units called "packets". Think of these as tiny digital envelopes. Each packet contains a portion of the data, along with information about where it came from and where it's going (source and destination IP Addresses), sequence numbers which is later read to assemble back to a complete data, and error-checking codes like checksums which identify probable errors during the transmission.
3. Addressing and Routing: Imagine you're sending a letter through the postal service. You write the recipient's address, and the postal system figures out the best route to deliver it. Similarly, each data packet is addressed with the sender's and recipient's information. These packets are then sent to routers, which are like digital post offices. Routers determine the best path for each packet to reach its destination. You can also think routers as traffic officers, who give direction to the packets.

1. Data Transmission: Once the packets are properly addressed, they're transmitted over physical infrastructures like fiber-optic cables, satellites, or wireless networks. This transmission happens at lightning speed, thanks to the speed of light and advanced technology.

1. Receiving and Reassembly: As the packets reach their destination, they're received by more routers. These routers put the packets back together in the correct order with the help of sequence numbers included in them. Think of it like receiving puzzle pieces and assembling them into a complete picture.
2. Data Decoding: Finally, the receiver's device or machine reverses the process after receiving the signals that carry the binary information through their wifi or ethernet, and converts those decoded binary bits back to their original format in which they were sent. For instance, binary pixel data received are converted into an image format which the device can display. Similarly, receivers can read the email, view the photo, or watch the video on their device. This step is where you see the content that was initially created in Step 1.

The mechanisms of the transmission is much more complex than explained, and involves other various steps like error detection and correction, bi-directional communication, acknowledge and handshake, encryption and security, etc. If you wish to learn more in detail, you can find plenty of contents in the internet.

So, in a nutshell, the internet is like a massive postal system for digital information. It takes data, breaks it into small pieces, addresses them, sends them across a vast network, reassembles them, and delivers the content to its destination.

Thank you for reading, and in the next article, we will read about "What happens when we search a url or link in the browser?"

Happy Learning!