How does Internet works?

   How the internet works? 

    

  How does the internet work? 

   In this blog I will tell you how internet works step by step The blog you are reading now traveled thousands of miles from a Google Data Center to reachyou. Let's learn how the internet works by getting to understand the details ofthis data's incredible journey. The data center which can be thousands of miles away from you has your blog stored inside it. how does this data reach your mobile phone or a laptop? An easy way to achieve this goal would be with use of satellites. From the data center, a signal could besent to the satellite via an antenna, and then from the satellite a signalcould be sent to your mobile phone via another antenna near to you. However, this way of transmitting signals is not a good idea. Let's see why. The satellite is parked nearly 22,000 miles above the earth's equator, so in order for the data transmission to be successful, the data would have to travel a total distance of 44,000 miles. Such a long distance of travel causes asignificant delay in receiving the signal. More specifically it causes hugelatency which is unacceptable for most internet applications so if this blog does not reach you via a satellite then how does it actually get to you? Well it is done with the help of a complicated network of optical fiber cables, which connect between the data center and your device. Your phone could be connected to theinternet via cellular data or any Wi-Fi router, but ultimately at some point yourphone will be connected to this network of optical fiber cables We saw at the beginning that the blog you are currently reading is stored inside a data center. To be more specific, it is stored in asolid-state device within the data center. This SSD acts as the internal memory of a server. The server is simply a powerful computerwhose job is to provide you the blog 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 via the complex network of optical fiber cables. Let's see how this is done. Before proceeding further we should firstunderstand an important concept which is the concept of an IP address. Every device that is connected to the Internet whether it is a server a computer or amobile phone is identified uniquely 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 sent to you reaches you precisely because of your home address. Similarly in the internet world an IPaddress acts as a shipping address through which all information reachesits destination. Your internet service provider will decide the IP address of your device and you are able to see what IP address your ISP has given to yourmobile phone or laptop. The server in the data center also hasan IP address. The server stores a website so you canaccess any website just by knowing the server's IP address. However, it isdifficult 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 which are easier for us to remember than the long sequence of numbers Another thing to notice here is that a server has the capability of storing several websites and if the server consists of multiplewebsites all the websites cannot be accessed with the server's IP address. In such cases additional pieces of information, host headers are used touniquely identify the website. However, for the giant web sites like Facebook.com or YouTube.com the entire data center infrastructure will be dedicatedto the storage of the particular website. To access the internet we always usedomain names instead of the complex IP address numbers. From where does the internet get IP addresses corresponding to our domain name requests. Well, for this purpose the internet uses a huge phone book known as DNS. If you know a person's name, but don't know their telephone number you can simply look itup in a phone book. The DNS server provides the same service to the internet. Your internet service provider or other organizations can manage the DNS server. Let's have a recap of the whole operation. You enter the domain name, the browser sends a request to the DNSserver to get the corresponding IP address. After getting the IP address, your browser simply forwards the request to the data center, more specifically to the respectiveserver. Once the server gets a request to accessa particular website the data flow starts. The data is transferred in digital format via optical fiber cables, more specifically in the form of lightpulses. These light pulses sometimes have to travel thousands of miles via theoptical fiber cable to reach their destination. During their journey they often have to go through tough terrains such as hilly areas or under the sea. There are a few global companies who lay and maintain these optical cablenetworks. These visuals show how the laying of optical fiber cables is done with the help of a ship. A plow is dropped deep into the sea fromthe ship, and this plow creates a trench on theseabed and to which places the optical fiber cable. In fact, this complex optical cable network is the backbone of the Internet. These optical fiber cables carrying the light are stretched across the seabed toyour doorstep where they are connected to a router. The router converts these light signals to electrical signals. An Ethernet cable is then used to transmit the electrical signals to yourlaptop. However if you are accessing the Internet using cellular data, from the optical cable the signal has to be sent to a cell tower and from the cell tower the signal reaches your cell phone in the form ofelectromagnetic waves. Since the Internet is a global networkit has become important to have an organization to manage things like IPaddress assignment, domain name registration etc this is all managed byan institution called ICANN located in the USA. One amazing thing about theinternet is its efficiency in transmitting data when compared withcellular and landline communication technologies. This blog you are watchingfrom the Google Data Center is sent to you in the form of a huge collection ofzeros and ones. What makes the data transfer in the internet efficient is the way in which these zeros and ones are chopped up into small chunks knownas packets and transmitted. Let's assume these streams of zeros and ones are divided into different packets by the server where each packet consists of sixbits. Along with the bits of the blog eachpacket also consists of the sequence number and the IP addresses of theserver and your phone. With this information the packets are routed towards your phone. It's not necessary that all packets are routed through the same path and each packet independently takes the best route available at thattime. Upon reaching your phone the packets are reassembled according to their sequence number. If it is the case that any packets fail to reach your phone and acknowledgement is sent from your phone to resend the lost packets. Now compare this with a postal network with a good infrastructure, but thecustomers do not follow the basic rules regarding the destination addresses. In this scenario letters won't be able to reach the correct destination. Similarly in the internet we usesomething called protocols for the management of this complex flow of datapackets. The protocols set the rules for data packet conversion, attachment of the source and destination addresses to each packet and the rules for routers etc fordifferent applications the protocols used are different. We hope this blog has given you a good understanding about how the internetworks, more specifically about the amazing journey of data packets from the data center to your mobile phone. This is how internet works and how it originates