7.3 Internet principles of operation

all connected allowing us to share information and communicate with

each other.

WWW

The world wide web is the series of web pages and files which are stored on the internet. You don't always use the world wide web when you're on the internet. For example, you might be making a Skype call or playing an online game.

WEB BROWSER

A web browser is a piece of software for converting the code in which web pages are written in to things you can see and understand. The web browser displays the text, images and video which are contained on the internet in to a clear structure so they can be browsed and viewed easily.

the World Wide Web. HTTP defines how messages are formatted

and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page

An intranet is a private network accessible only to an organization's staff. A wide range of information and services from an organization's internal IT systems are unavailable to the public, unlike the Internet.

INTRANET

how devices communicate. how the communication will start
the transmission

speed
the significance of the bits being transmitted
how the bits will be delivered (one at a time or in groups of 16 for example)
error checking procedures used The Internet Protocol is known as TCP/IP.

unique 32-bit reference number that is allocated to devices on

a computer network that uses the Internet Protocol.
IP addresses are stored as 32-bit numbers 2^(32) = 4 billion possible unique IP addresses
For our convenience IP addresses are usually displayed as a series of 4 decimal numbers, each one representing 8 bits of the original binary address.
32-bit binary version: 110010011010000001011011011111111
11001001 201
10100000 160
01011011 91
01111111 127
decimal version: 201.160.91.127
Some IP addresses are reserved for private network ranges e.g.
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255

address (MAC address) is a unique 48-bit number assigned to

a network interface card (NIC) to identify it on a LAN. Because they are so long, MAC addresses are usually displayed in hexadecimal.
48-bit binary version: 000000000000100101111100111100011111011110000101
hexadecimal version: 00-09-7C-F1-F7-85
MAC addresses are stored as 48-bit numbers 2^(48) = 281 trillion possible unique MAC addresses.

reference to a web resource that specifies its location on a computer network and

a mechanism for retrieving it.

Domain Name System (DNS)

The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services, or other resources connected to the Internet or a private network.

address contains (running from left to right):
http(s)
the domain name -

the name of the website
an area within that website – like a folder or directory
the web page name – the actual page that you are viewing
For example: http://www.bbc.co.uk/nature/life/frog

Web addresses

In this example from BBC Nature:
http is the protocol
www.bbc.co.uk is the domain name stored on a DNS
/nature/life/ is the folder structure leading to where the web page is located
frog is the requested web page