The Internet

The internet is one of the greatest creations of man-kind which allows us to communicate with each other regardless of distance and time as long as we are connected to it.

What is the Internet?

The Internet is a vast network that connects computers all over the world, it is regarded as the network of networks in which any computer with permission can get information from another computer. The internet moves data from one place to another so we can chat, browse and share information.

HOW THE INTERNET WORKS

• Data Sever : This stores your all information, to be more specific it is stored in the Solid State Device(SSD) within the data center, it accesses the memory of the server, the server is simply a powerful computer that provides requested stored content

• Satellite Network : with the use of a satellite, information can be sent to your computer via a signal sent from the data server's antenna then through another antenna close to you, but this could be a problem because the distance of the satellite and antenna is wide, this could lead to delay of information delivery and huge latency(delay).

• Optical Fibre Network : This is the approved way of sending information, these cables and played all over the world which connects between the data sever center and your device. Your device maybe be connected to the internet wirelessly but at some point, your device would be connected to these cables

• IP Address : Every device that is connected to the internet whether a sever, computer, or mobile is identified uniquely by a string of numbers called an IP Address. An IP Address can be thought of as your home address. It is an address where information is sent to. Your internet service provider would determine your IP address which would be able to see. Servers in the data center also have an IP address, the server stores a website and you can access that website just by knowing its IP address.

• Domain Name : To know so many IP addresses is very difficult one has to study the numbers and dots. To solve this problem Domain names are given to these addresses, such as Youtube.com, Facebook.com, etc. A sever consists of multiple websites other websites cannot be accessed by the server IP address in that case you would need a host header.

  Host-Header is the additional information added to an IP address to uniquely identify a web domain (HTTP).

• Domain Name System(DNS) : The internet gets the IP address from the DNS, it is like a phone book, if you don't know a person phone number but knows the person name you can look into the phone book and get it, this also works for the Internet. When you enter the domain name in your browser, the browser sends the request to the DNS server to get the corresponding IP address, after getting the IP address the browser forwards the address to the respected server.

• Data Flow : once the server gets a request to access a particular website the data flow starts the data is transferred in digital format via the fiber cable more specifically in the form of light pulses, they travel thousands of miles to reach their destination. These cables are stretched around the world and then connected to your router the router converts the light signals to electrical signals and an ethernet cable is used to transfer the electrical signal to your laptop.

  If you are connected to the internet wirelessly the light signal is sent to a cell tower and from the cell tower, the signal reaches your phone through electromagnetic waves. Videos are sent to you in a form of huge collections of 0s and 1s, what makes data transfer in the internet efficient is the way the 0s and 1s are chopped into packets.

• HTTP : HTTP is the acronym of HyperText Transfer Protocol, it is the underlying network protocol that allows the transfer and fetching of hypermedia documents(images, audios, text, videos, spreadsheet, etc) between a server and a client on the web. The "HTTP" in a domain name is called a scheme in which resources are sent over unencrypted connections. It is a stateless protocol, transactions made using HTTP are independent it is not related to any other transactions, but your transactions can be tracked by the server. HTTP uses TCP(Transmission Control Protocol) as its transport protocol.

  TCP defines how data is transmitted, it determines how the data is formatted or how packets are sent. TCP has a lot more functionalities.

  When a client sends a request its actions are specified actions such as. GET, POST, DELETE, these actions are performed by the server these actions are called Methods or Verbs. The client needs a response, servers have response status codes this is how the server responds to the client, by using numbers such as 200 for "OK", 400 for "Bad request" there are a lot of these numbers, they are majorly called response status codes and it is the job of the back-end engineer to return the proper status cause.

  • HEADERS : These are custom information added to your request and your responses, a request can have a header of a content type that is the type of file you want your request to be in it could be a JSON file or a Text file, the format depends on the client's choice, A server can send a response with a header an example is a cache-control header which is a policy of where caching is being managed by the server.

CLIENT AND SERVER

When information is requested for the sender is knowns as the Client and the receiver is known as the server, then a response is sent back to the client based on that request in simple terms client and server is the relationship between a client and a server.

For example, when you open a profile on Facebook and you want information about your information you click on your profile which stores up all your data, a request is sent to the Facebook server telling it you want to see your profile contents the server receives the request and responds by sending you the information you need. In some cases there are hybrid clients, they act as servers they get information from the server when another client needs that information they give it to the client.

Roles Of A Back-end Engineer In Internet Applications

The back-end engineer is responsible for the server-side web application, the back-end engineer makes a database in the server where all data is stored, they are responsible for making technologies that power the components of the server-side(a server, an application, and a database). They use developer's tools to make clean codes, portable, and well-documented codes. The reason why a website can bring up pages is because of the work of a back-end engineer, each time you log in and your information concerning that website comes up it is the work of a back-end engineer.

Back-end engineers would need knowledge in server-side languages such as PHP, Ruby, Java, .NET to build applications. MySQL, Oracle, and SQL Server, which allows them to edit, find or save data and send it back to the user.

Roles Of A Front-end Engineer In Internet Applications

A front-end engineer does the user-view of a website, the architecture of the websites, a front end engineer must be fluent in HTML, CSS, and Javascript programming, they need to be knowledgeable in frameworks like Bootstrap, Foundation, AngularJS, Backbone, and EmberJS which displays good contents on every device, they would need libraries like jQuery and LESS. A front-end engineer must make the user's interaction with the website convenient.