A network is defined as data communication system that interconnects computer systems. A network may be composed of different combination of LANs (Local area Networks), MANs (Metropolitan Area Networks) or, WANs (Wide Area Networks). At the simplest a network consists of two computers or devices with a length of wire between them, facilitating communication.
Internet is a worldwide network of computer networks.
Internet was born as a result of technological advancements that have enabled virtually all computers to be networked together. Around 1980, the Advanced Research Project Agency, part of the Department of Defence, setup the first part of what the world today knows as the Internet.
How Does Internet Work?
The thing that characterizes the Internet is how data transferred from one computer to another. Here is what happens to a piece of data when it is transferred over the Internet:
- It is broken up into a whole lot of same-sized pieces called packets.
- A header is added to each packet that explains where it came from, where it should end up and how it fits in with the rest of the packets.
- Each packet is sent from computer to computer until it finds its way to its destination. Each computer along the way decides where next to send the packet. This could depend on things like how busy the other computers are when the packet was received. The packets may not all take the same route.
- At the destination, the packets are examined. If there are any packets missing or damaged, a message is sent asking for those packets to be resent. This continues until all the packets have been received intact.
- The packets are reassembled into their original form.
Each computer connected up to the Internet has software called TCP/IP (Transmission Control Protocol / Internet Protocol), which is responsible for receiving, sending and checking packets. TCP/IP is the glue of the Internet.
World Wide Web (WWW)
The World Wide Web (WWW or simply the web) is a collection of electronic documents (called web pages) that are linked together like a spider web.
These documents are stored on computers called servers located around the world.
A Web Server is a computer that:
- Stores web pages
- Responsible for accepting requests from users and serve them with web pages.
Some important web server programs are IIS (Internet Information server), Apache.
Hyperlink is an element in an electronic document that links to another place in the same document or to an entirely different document or other resource.
Hyperlinks usually appear as underlined text and in a different color, but they may also appear as graphics, such as buttons to click. Hyperlinks may link to another place in the same page, to a different page, to play an audio or video file, to download a file, to set up a message to an e-mail address, and to link to other Internet resources.
HTML (Hypertext Markup Language)
Hypertext Markup Language is a language that consists of certain key words called Tags, used for writing the documents on the web.
A web page is an electronic document written in a computer language called HTML (Hypertext Markup Language). Web pages can contain text, graphics, video, animation, and sound, as well as interactive features, such as data entry forms.
Each page has a unique address known as a URL (Uniform Resource Locator) that identifies its location on the server. Web pages usually contain hyperlinks to other web pages.
A website is one or more web pages, belonging to a particular company, university , government or an individual. The first page is called the home page, which acts like an index, indicating the content on the site.
From the home page, you can click hyperlinks to access other web pages.
URL (Uniform Resource Locator)
Every page on the web has a unique address, called Uniform Resource Locator, URL. A URL indicates where the web page is stored on the Internet.
IP (Internet Protocol) Address
Every host (a computer linked to the Internet) on the Internet has a unique host number. This number is called the Internet Protocol address, or IP address. The IP address is a unique address, generally written in the format xxx.xxx.xxx.xxx, xxx represents a 3 digit number that varies between 0 and 255.
DNS (Domain Name System)
Every host (computer linked to Internet) has a unique host number called IP address. You can connect to any host through IP address only, but it is difficult to remember the 4-digit number of hosts.
To resolve this, domain-name is the solution. Domain name is a unique name of the individual host computer on the Internet With this every computer on the internet now have a both a domain name and IP address. To connect to any host through domain name requires some mechanism that will convert your domain name into IP address.
DNS, Domain name System is the standard for resolving names to addresses. It is used mostly to translate between domain names and IP addresses.
A web browser is the software program, used to access the World Wide Web. A browser retrieves data from remote web servers and displays a web page. Through this tool user sends their request to Internet server to access the information, Server process the request and responds with required information as a web page to the user.