How does the INTERNET work? | ICT #2

How

does

the

internet

work

? The video you're watching traveled thousands of miles from a Google data center to reach you. Let's learn how the Internet

work

s by understanding the details of the incredible journey of this data. The data center, which may be thousands of miles away from you, has your video stored inside it. How

does

this data reach your mobile phone or laptop? A simple way to achieve this goal would be through the use of satellites. From the data center, a signal could be sent to the satellite through one antenna, and then from the satellite a signal could be sent to your mobile phone through another nearby antenna.

However, this way of transmitting signals is not a good idea. Let's see why. The satellite is stationed nearly 22,000 miles above the Earth's equator, so for data transmission to be successful, the data would have to travel a total distance of 44,000 miles. Such a long distance causes a significant delay in signal reception. More specifically, it causes enormous latency that is unacceptable for most Internet applications, so if this video doesn't reach you via satellite, how does it actually reach you? Well, it is done with the help of a complicated network of fiber optic cables, which connect between the data center and your device.

Your phone could be connected to the Internet through mobile data or any Wi-Fi router, but ultimately at some point your phone will be connected to this network of fiber optic cables. We saw at the beginning that the video you are currently watching is stored inside it. a data center. To be more specific, it is stored on a solid state device within the data center. This SSD acts as the internal memory of a server. The server is simply a powerful computer whose job is to provide you with the video or other stored content when you request it.

Now the challenge is how to transfer the data stored in the data center specifically to your device through the complex network of fiber optic cables. Let's see how this is done. Before we continue, we must first understand an important concept which is the concept of IP address. Each device that is connected to the Internet, whether a server, computer or mobile phone, is uniquely identified by a string of numbers known as an IP address. You can consider the IP address similar to your home address, that is, the address that uniquely identifies your home. Any letter they send you arrives precisely at your address.

Similarly, in the

internet

world, an IP address acts as a forwarding address through which all information reaches its destination. Your Internet Service Provider will decide the IP address of your device and you will be able to see what IP address your ISP has given to your mobile phone or laptop. The data center server also has an IP address. The server stores a website so that you can access any website just by knowing the IP address of the server. However, it is difficult for a person to remember so many IP addresses. So, to solve this problem, domain names like youtube.com, facebook.com, etc. are used, which correspond to IP addresses that are easier for us to remember than the long sequence of numbers.

Another thing to keep in mind here is that a server has the ability to host multiple websites and if the server consists of multiple websites not all websites can be accessed with the server's IP address. In such cases, additional data, host headers, are used to uniquely identify the website. However, for giant websites like Facebook.com or YouTube.com, the entire data center infrastructure will be dedicated to storing the particular website. To access the Internet we always use domain names instead of complex IP address numbers. Where does the Internet get the IP addresses corresponding to our domain name requests?

Well, to do this the Internet uses a huge telephone directory known as DNS. If you know a person's name, but don't know their phone number, you can simply look it up in a phone book. The DNS server provides the same service to the Internet. Your Internet service provider or other organizations may manage the DNS server. Let's summarize the entire operation. Enter the domain name, the browser sends a request to the DNS server to obtain the corresponding IP address. After obtaining the IP address, your browser simply forwards the request to the data center, more specifically to the corresponding server.

Once the server receives a request to access a particular website, the data flow starts. Data is transferred in digital format through fiber optic cables, specifically in the form of light pulses. These light pulses sometimes have to travel thousands of kilometers through fiber optic cable to reach their destination. During their journey they often have to cross difficult terrain, such as mountainous areas or under the sea. There are a few global companies that install and maintain these optical cable networks. These images show how fiber optic cables are laid with the help of a ship. From the ship a plow is dropped into the depths of the sea, and this plow creates a trench on the seabed and into which the fiber optic cable is placed.

In fact, this complex optical cable network is the backbone of the Internet. These light-carrying fiber optic cables stretch along the seafloor to your front door, where they connect to a router. The router converts these light signals into electrical signals. An Ethernet cable is then used to transmit the electrical signals to your laptop. However, if you access the Internet using mobile data, from the optical cable the signal must be sent to a cell tower and from the cell tower the signal reaches your cell phone in the form of electromagnetic waves. Since the Internet is a global network, it has become important to have an organization to manage things like IP address allocation, domain name registration, etc.

All of this is managed by an institution called ICANN located in the USA. One amazing thing about the Internet is its efficiency in data transmission compared to fixed and cellular communication technologies. This video you're watching from Google Data Center is sent to you as a huge collection of zeros and ones. What makes data transfer on the Internet efficient is the way these zeros and ones are broken up into small fragments known as packets and transmitted. Suppose the server splits these streams of zeros and ones into different packets, where each packet consists of six bits. Along with the video bits, each packet also consists of the sequence number and IP addresses of the server and your phone.

With this information the packets are routed to your phone. It is not necessary for all packets to be routed along the same path and for each packet to independently take the best route available at that time. Upon reaching your phone, the packets are reassembled based on their sequence number. If any packets do not reach your phone, an acknowledgment is sent from your phone to resend the lost packets. Now let's compare this to a postal network with good infrastructure, but customers do not follow the basic rules regarding destination addresses. In this scenario, the letters will not be able to reach the correct destination.

Similarly, on the Internet we use something called protocols to manage this complex flow of data packets. Protocols set the rules for converting data packets, connecting source and destination addresses to each packet and rules for routers, etc. For different applications, the protocols used are different. We hope this video has given you a good understanding of how the Internet works, more specifically the incredible journey of data packets from the data center to your mobile phone. Don't forget to support us on patreon.com. Thank you!