Kartlar: 5 - Computer Networks, The Internet and the World Wide Web (WWW) (Leaving Cert)

World Wide Web (WWW)

A network of connected files (web pages, images, videos, etc.) hosted on the Internet.

The Internet

The underlying physical network of hardware (computers, servers, cables, undersea cables, routers, switches, etc.) that enables the World Wide Web to function.

Internet Connection Technologies

Copper wires, fiberoptic cables, wireless satellites, Wi-Fi etc.

Tim Berners-Lee

Invented the World Wide Web in 1989.

Tools used to design the World Wide Web

HTML, CSS, and JavaScript.

Client/server model

A network architecture in which each computer is either a client or a server. Servers are powerful computers dedicated to managing the clients. Clients are PCs on which users run applications. Clients rely on servers for resources..

Web browser

Used by a client computer to request a web page or data from a server.

Communication Protocol

A set of rules that describe how to transmit data across a network.

HTTP/HTTPS

Communication protocols used when a client browser is requesting a web page from a web server, and they are responsible for transferring data between the client and server.

DNS (Domain Name System)

Maps human-readable URLs (Uniform Resource Locators) to IP addresses. It is important because it makes it easier for users to access websites without needing to remember the IP addresses of the servers hosting those websites.

HTTPS

Data is encrypted before being sent between the client and server. This provides an additional layer of security.

Client-Server Protocols

Application, transport, network and physical.

Application Layer

HTTP and HTTPS are protocols within this layer.

Transport Layer

TCP (Transmission Control Protocol) is the protocol within this layer.

Network Layer

IP (Internet Protocol) is the protocol within this layer.

Physical Layer

WiFi is one of the protocols within this layer.

TCP Protocol

Ensures that data is transmitted in a reliable and ordered manner between devices by establishing a connection between them. It provides features such as error detection and ensures that data is received in the correct order.

IP Protocol

Allows data packets to be delivered across a network.

Cloud Computing

Using online software applications rather than tools and information stored on a personal computer.

Computer Network

A system that allows computers to communicate and share resources with each other.

LAN (Local Area Network)

A network that connects computers within a limited geographical area, like a home, school, or office building.

Ethernet

A popular LAN technology that uses cables to connect computers.

Media Access Control (MAC) address

A unique identifier assigned to each computer at manufacturing, that allows for addressing specific devices on a network.

Switch

A device that forwards data packets between different segments of a network based on their destination MAC addresses.

Router

A device that sends data across a network from source to destination.

Data Packet

A small unit of data transmitted over a network.

Internet of Things (IoT)

A network of physical devices embedded with sensors and software, connected to the internet, allowing them to collect and exchange data.

IP Address

A unique numerical label assigned to each device connected to a network that identifies its location.

Wide Area Network (WAN)

A network that spans a large geographical area, connecting LANs and other networks.

Internet Service Provider (ISP)

A company that provides internet access to customers. Vodafone is an example.

Checksum

A mathematical value calculated to verify the data integrity of a packet. Used to check for errors when sending data packets.

Hyperlink

A link within a web page that, when clicked, directs the user to another web page.

Hypertext

Text containing hyperlinks.

Uniform Resource Locator (URL)

A unique address specifying the location of a web resource on the internet. www.google.com is an example.

Web Server

Comprises hardware for storing web pages, and software for delivering web pages to a user.

HTML (Hypertext Markup Language)

A markup language used to create web pages.

HTML Tag

An element in an HTML document that defines how content should be displayed or interpreted.

is an example.

Search Engine

A software application that searches for information on the internet.

Search Algorithm

A set of rules used by a search engine to rank search results.

Net Neutrality

The principle that all internet traffic should be treated equally, regardless of its source or destination.

Bandwidth

The amount of data that can be transmitted over a network in a given amount of time.

Topology

The layout chosen to connect network devices together (Ring, Star, Line etc.).

CSS (Cascading Style Sheets)

A language that can be used to style a web page via changes in colours, sizes, spacing, fonts, and more

Inline CSS

When CSS is used to apply a unique style to a single HTML element. For example,

This is a Blue Heading

Internal CSS

When CSS is added into a HTML file between tags in the head. This allows the CSS rule to be used on multiple elements within the same HTML page.

External CSS

When CSS is stored in a separate file, which can be attached to multiple HTML pages. Very useful when controlling the style of a large website with many web pages.

Sublime Text

An IDE (Integrated Development Environment) for writing web pages (HTML, CSS & JavaScript).

tag

A HTML tag used to display HTML elements in a web browser

tag

A HTML tag used to store metadata (data about data), including page titles and links to external CSS files.

tag

A HTML tag used to show an image.