How does an ISP Work

ISP stands for Internet Service Provider. These are the agencies that help you connect your computer to the Internet. The first cross country link through Internet was done in 1970. But, till date there are many people who are not aware of the working of the world wide web. The answer is the ISP, which connects you to the Internet. Here, in this article, we will try to understand how does and ISP work.

There are various terms related to the Internet. For explaining how an ISP works, certain terms need to be presented before starting with the actual working.

Terms Related to ISP
Modem: Every computer that connects to the internet has to do so using a modem. The full form of modem is 'modulator-demodulator'. The function of the modem is synonymous to its name. It modulates the data and converts it into digital form before passing on the information to the Internet service provider. The data that it receives from the Internet service provider is also in the form of digital signal, and so it demodulates the data.

IP Address: IP stands for Internet Protocol. Every computer that connects to the internet is assigned an IP address by the ISP. When we type in the name of a particular website in our web browser, we are actually typing in the Internet Protocol address of the website. The IP address in this case is the address of the server machine that holds the desired web pages. It is generally of the form n.n.n.n, where n stands for a number.

DHCP: 'Dynamic Host Control Protocol' in its abbreviated form is known as DHCP. A protocol is nothing but a set of rules that decides the process of doing a work. The dynamic host control protocol is used by the ISP to assign temporary addresses to any of its subscribers who intend to connect to the Internet.

Backbone of ISP: This is the point that connects your ISP to the Internet. The ISPs buy a particular range of bandwidth for the working of its backbone. It is through this bandwidth that information is sent or received.

The ISP Facility
The Internet service provider carries out its entire functioning in a room called the data center. The advanced data centers consists of various equipments. However, for the ease of explaining how an ISP works, I will introduce you to the basic equipments which carry out the Internet connection procedure. A pool of modems inside the data center is used to connect every subscriber to the Internet. Once a modem in the modem pool receives the information, it connects the subscriber to the backbone. The entire functioning of the modem pool is controlled by algorithms running in a computer to which the modems are connected. This setup of modems is generally referred to as the ISP port server.

How does an ISP Work?
Let's start with the procedure right from the local computer. Home computers connect to the ISP using telephone cables or broadband Internet connections. Large networks like that of educational institutes connect to the ISP using a D1 line. The way of logging into the ISP is however same for both. For connecting to the Internet, you will need a modem and an ISP subscription. Let's try to understand the entire procedure in a step by step process:

• The first step is to login into the ISP using the user information provided to you by your ISP. Here, you enter the username, password and telephone number of the ISP.
• Once the ISP receives your information in its modem pool, it verifies if you are an authentic user or not.
• Once the user authentication process is done, the ISP provides you with a dynamic IP address using the DHCP.
• If you have bought a static IP from your ISP, then this step is not required. However, buying a static IP will cost you a lot.
• Now, you are allowed to browse any web page through your web browser. When you type in the name of the URL on the address bar, you are actually requesting for the IP address of the server machine, that holds those web pages.
• The information is received at the modem pool. Once this information is received, the ISP connects the subscriber to the modem pool.
• The requested server machine is reached through an array of dedicated lines and routers.
• Once the ISP finds the required IP address, it transfers the requested web pages to the source IP address.

Cooling devices and backup power supplies are among the other components used by an ISP. These components are of utmost importance for the effective functioning of the ISP. For completely explaining how an ISP works, volumes can be written. However, here I have tried to give a very basic explanation for any layman Internet user to understand, how does an ISP work?