Introduction to the internet
Published: 2020-06-14 21:18:24

                                                                      
                              #The Internet

In simplest terms, the internet is a network of machines (servers, clients, routes, etc) connected to a media (fiber, wifi,etc) that allows communication among devices. Its origins go back to the 1960s, and was originally called ARPANET.

                     ##Packets and Routers

When sending a file or message over the internet from one computer to another, the files are always too big and so are broken into packets. Each file name includes a “header” information that lists the file name, the origin and destination computers, and the order of the packet; e.g. “packet #5 of 22 total for the file names such and so” 
Router is a special-purpose device which forwards data packets to the appropriate parts of a computer network. It’s the traffic cops of the internet.

This method of traffic control and flow is called packet-switching, switching means routing.

The process is like mailing a 10-page letter to a friend through the postal service, but instead of sending it all in one envelop, putting each page in its own envelop and sending them separately.

The routers are constantly communicating with each other in order to have up-to—speed “traffic reports.” If, for example, one router is experiencing heavy traffic loads or goes offline, the other routers will send packets around it. (i.e to other routers) until traffic subsides or router is back online. A packet may therefore take a very circuitous route to its destination. Even the individual packets that make up the file may take different routes through the network. Some packets of a file sent from a computer in Abuja to a computer in Port-Harcourt, may end up travelling through routes in Kogi, Kaduna, and Sokoto while others may take route through Lagos, Osun and Abia.

                       ##TCP/IP and Domain Names

Transfer Control Protocol (TCP) is a software that breaks messages into packets from the sending computer, and recombines them at the receiving computer. It also provides an error-checking mechanism for lost or delayed packets.

Internet Protocol (IP) is also a software that runs the routers, performing the basic task of moving packets as quickly as possible from one router to another. 

The routing of packets to their correct destination obviously requires some sort of addressing scheme. Every host device on the internet has a unique IP address, made up of four numbers such as 192.56.215.131, each of the numbers may be between 0 and 255. 

Using all possible combinations of the four numbers in an IP address yields approximately 4 billion addresses. Which was originally OK, but the explosive growth of the internet prompted the Internet Engineering Task Force (IETF) to develop IPv6 which allows for 64 billion billion billion addresses, enough so that we could assign an IP address to every grain of sand on the earth.  

The IP numbers based on address suited the computers just fine, but were too sparse for humans. Imagine, the confusion that would result if there were no street names but just address numbers. Instead of “I live at 216 Main Street, “it might be “I live at 192.56.215.131.  An Internet Domain Name System (DNS) is therefore laid on the IP address to make it readable to humans.

The internet is divided into different country domains, consisting of all the hosts on the network of the country. The host is given a name, we refer to it with the syntax below:
          hostname.organization.countryname
       www.louvre.fr (official site of the Louvre Museum in Paris)

Most times, instead of the domain being the country code, it consists of a code corresponding to the type of organization to which the host belongs. The codes for the major types are 
.edu, .com, .gov, .mil, .org.

A special organization the Internet Corporation for Assigned Names and Numbers (ICAAN), oversees the management and assignment of names, as well as IP addresses. 
A few examples:
www.wikipedia.org 
www.redcross.org
www.facebook.com
www.whitehouse.gov 
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