ICT Unit 1

The Internet

A group of inter-connected networks.

World Wide Web

A collection of web pages stored on computers all over the world, accessed via the internet, with no central storage and no owner.

Uniform Resource Locator

A URL is a web address where all web addresses are unique.

Parts of a Web Address (Example: abc.com)

Breakdown consisting of hosted on the WWW, name of the organization, a company, and folder location and filename on the site.

Scheme

The protocol used to access the web resource (e.g., https).

Domain Name

The unique name that identifies a website on the internet.

Port

A technical gate or communication endpoint used to route data traffic.

Path to the file

The specific folder directory where the file is stored on the server.

Query

Parameters or search strings sent to the web server.

Fragment

An internal anchor pointing to a specific subsection of the web page.

Top Level Domains (TLD)

Extensions at the end of a web address indicating its country or purpose (e.g., .uk, .fr, .es, .de, .cz, .com, .org, .gov, .edu).

IP (Internet Protocol) Addressing

Every computer in the world has a separate, unique address (series of numbers); data can be sent to these addresses to request or display a web page, for example.

DNS (Domain Name Server)

Converts a web address or URL into the correct IP address for the computer that the website sits on.

HTTP

HyperText Transfer Protocol.

Protocol

A set of rules; HTTP defines the rules used by web browsers and servers to exchange information; if everyone follows the same set of rules, everything works.

Data Packets

Data transmitted over the Internet is broken down into smaller chunks or packets to be sent; the destination and sender's addresses are added; each packet is numbered, sent separately, then put in the right order again at the other end.

Bandwidth

The amount of data that can be carried at a time.

Downloading

Copying data from one device (server, the internet) to another that is usually smaller, such as your phone or laptop, often done via the internet; from elsewhere to you.

Uploading

Copying data from one device to another that is larger or somewhere else (server, the internet); from you to elsewhere.

Wireless connectivity

Must be close to a WiFi hotspot or router; slower than a wired connection; interference from walls and furniture; greater security risk; no need to be physically connected; can connect mobile devices.

What is broadband?

A high-speed connection to the internet that has replaced the use of dial-up connections.

Fibre optic

Glass thread is used in modem cables, with up to 1,000 fibres in a single cable; potential bandwidth can be many terabytes per second.

Network

Standalone devices connected together to share resources.

Network Advantages

Share devices (printers, scanners); easy to share folders and files; backups taken care of centrally.

Network Disadvantages

Security breaches; if the network shares 1 internet connection, the whole network can slow down; more difficult to manage.

WAN

(Wide-Area-Network); covers large geographical area; Ex. ATM, internet.

LAN

(Local-Area-Network); covers small geographical area; Ex. School, Home.

Network Interface Card (NIC)

Can be wired or wireless; essential to connect to a network; inside computers, tablets and mobile phones.

Router

Traffic policeman for data packets; sends them on their way in the best direction.

Hub

Central, multi-plug adaptor for computers and printers in a network; enables communication between devices.

Switch

Smart multi-plug adaptor; reduces network traffic and increases speed.

Bus Topology

A network setup where a central main cable connects a server, a printer, and all workstations, terminating at both ends.

Bus Topology Advantages

The simplest and cheapest to install and extend; failure of one device does not affect the rest of the bus network.

Bus Topology Disadvantages

If the main bus cable fails then the whole network will fail; performance of the network slows down rapidly with more nodes or heavy network traffic.

Ring Topology

A network layout where devices are connected in a continuous circular loop.

Ring Topology Advantages

One-way system so not affected by heavy traffic.

Ring Topology Disadvantages

Cable failure anywhere will affect the whole network; need to 'break' the ring in order to add a new device; all devices must be switched on.

Star Topology

A network layout where all nodes are individually connected to a central hub or switch.

Star Topology Advantages

Fastest performance; easy to install and to expand with extra nodes; a failure in the minor cables will only affect one node.

Star Topology Disadvantages

Uses the most cable which makes it more expensive; an extra hub or switch further increases the cost.