Children know how to confuse adults with a simple question about everyday things. In our “Explain to a child” section, you will learn how modern technologies work so as not to disgrace yourself on occasion. Let's start with the Internet.
What is the Internet anyway?
First of all, the Internet is a network. When a computer goes online, it connects to one of its many nodes and downloads packets of information to itself. These packages contain website content, multimedia, technical data for online games, and so on and so forth.
How do Internet users communicate with each other?
The Internet is based on a set of special rules, or protocols. They establish how network participants (computers, servers, programs, smart devices) should send data to each other, which packets are required for what purposes. Different devices and programs use different protocols in different situations and for different purposes. For example, the Internet Protocol (IP) sets out how computers should send information to each other. And the Transmission Control Protocol (TCP) makes it possible to ensure that computers receive the full set of packets that make up the site they need.
So that all network members do not get in the way of each other too much, they are bred across different layers of the Internet. The original concept of the Internet involved four such layers; in the most detailed model, there are seven of them, including the physical one — cables that carry data.
How does the wired structure of the Internet work?
Yes, although the Internet is considered a virtual space, it has the most physical basis. All continents are connected by wires that line the ocean floor. Oddly enough, the deeper such a cable lies, the thinner it is — in the deepest parts their diameter does not exceed 3 cm, and closer to the surface, on the contrary, they reach 6 cm. The reason is that virtually nothing can happen to the cable in deep water (starting at 2 km), so engineers are reducing the thickness of the protective layers.
The main threat to these wires in the ocean is sharks, which love to nibble on them for unknown reasons. The Internet is protected from their teeth with Kevlar, a very durable and very lightweight composite material that is used in modern tires, body armor and much more.
How does the Internet get to our homes?
Ultimately, submarine cables come to major traffic exchange centers called Tier 1 Internet Service Providers (ISPs). These companies sell Internet access to smaller providers (Tier 2 ISPs), which provide communication at the state level and work with third-tier providers and large companies. It is with these latter that private users enter into contracts.
This entire route has wires that lead directly to your apartment. When you're outside, pay attention to the cables that run from one roof to another. For the most part, these are also Internet wires. If you look at this whole picture, it becomes clear where the expression “World Wide Web” comes from.
How does a computer open websites?
We figured out the wires, now let's talk about how sites appear on the computer screen.
The content of the sites is stored on web servers. When you enter a URL into the browser bar, you're telling the program to contact the appropriate server and download the data it provides. Computers do not use our usual website addresses (domains), so the browser first specifies what IP address is assigned to the requested domain.
To do this, he uses the Domain Name System (DNS), which, like a phone book, stores existing IP addresses and their corresponding “human” names. This system is based on DNS servers that communicate using their own protocols. In order not to create an unnecessary load on this infrastructure, the site known to the computer can be stored locally — in its own DNS cache. This is where he first tries to find the right IP address, and in case of failure, he already contacts external sources.
After determining the IP address, the browser asks the server for the content of the desired site. He first sends him the page structure, which is written in HTML. The browser parses this code and finds what needs to be loaded additionally — special styles, interactive JavaScript elements, and other components. When all content is loaded, the browser “draws” the page (this process is called rendering). At the last step, he substitutes images — this is the hardest part of the site, so they leave it for the final. If everything went well, you will see the site you need on the screen.
This is how the Internet works in two sentences:
- When you enter an address into the browser, it converts it to DNS format, finds the right server, and asks it for data.
- Servers send web page content over wires that stretch thousands of miles until it reaches your home.
