AKB4000006: What is the internet?

By @CanadianTech

Published 5 Feb 2017 rev 1.0

The Internet is a network of billions of devices that can literally be anywhere. Devices can be computers, printers, cell phones, tablets, cameras — even your refrigerator or thermostat.  In almost all cases, your computer is constantly connected to the Internet.

1. Each device must have a unique address. These addresses are called Internet Protocol (IP) addresses. They actually look something like, 123.245.1.78 – a series of four numbers that can range from 0 to 255. Your InternetService Provider (ISP) assigns one to your modem, although they may dynamically change it. When you enter an address (called a Universal Record Locator (URL)) likehttp://www.google.com in the address bar of your browser, it is sent to your Internet Service Provider (ISP), which then finds the correct IP address for that URL and sends your request along. The computer that does this conversion is called aDomain Name Server (DNS).  NOTE: IPV6 is slowly coming into use.  The components of the address are hexadecimal instead of straight decimal.
2. What really runs the Internet is a large group of mostly pretty big computers collectively called the backbone. Your computer is connected to the Internet by your ISP.  This connection is what you are paying for.
3. The next important principle that makes the Internet work is packets. All communication is broken into small pieces calledpackets. A packet is like a little envelope. It has an address where it is to be delivered and one that tells where it came from. When you receive a web page or an email, your computer is receiving a large number of packets which it must assemble in the right order. A web page or email may consist of hundreds if not thousands of packets.
4. The next important thing about the Internet is that its basic design does not have any planned routes. It is like a spider web, which is why it is called the World Wide Web (WWW). Each packet can be bounced from one computer to another in an unlimited number of steps. So, packets arrive in a different sequence than sent, because they may have followed completely different paths. There is no guaranteed delivery on the Internet, so packets can be lost, although that is rare. If one is missing, many attempts will be made to resend. All of this becomes very obvious when you use a web camera or use the web to talk with someone. For web pages or email, your computer will eventually put all the packets in order and present an orderly result.