H446 Section 5 Networks and Web Technologies

Internet

A global network of networks that allows computers to communicate using standardized protocols, enabling data exchange and access to information.

ARPANET

1960s US defence project to enable distant departments to collaborate.

World Wide Web

A system of interlinked hypertext documents and multimedia content accessed via the Internet, allowing users to navigate and share information using web browsers.

Internet Service Providers

Companies that provide access to the Internet, allowing individuals and organizations to connect and use online services.

Uniform Resource Locator

(URL) is a reference or address used to access resources on the Internet, specifying the location of a resource and the protocol used to retrieve it.

Internet registrar

An organization that manages the reservation of Internet domain names, ensuring that domain names are unique and facilitating the registration process for individuals and businesses.

Internet Registries

Organizations that maintain databases of registered domain names and their associated information, ensuring the integrity and availability of the domain name system.

ICANN

The Internet Corporation for Assigned Names and Numbers, a nonprofit organization responsible for coordinating the global domain name system and ensuring the stability of the Internet.

Domain Name System

A hierarchical system for naming resources on the Internet, allowing users to access websites using human-readable addresses instead of numerical IP addresses.

IP address

A unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.

IPv4 format

A 32-bit numerical address format used in the Internet Protocol version 4, typically represented in decimal as four octets separated by periods.

IPv6 format

A 128-bit address format used in the Internet Protocol version 6, represented as eight groups of four hexadecimal digits separated by colons.

Fully Qualified Domain Name

A complete domain name that specifies its exact location within the Domain Name System (DNS), including the top-level domain and all subdomains. Includes the host server name e.g. www, mail or ftp depending on whether the resource is on a web, mail or ftp server.

Router

A device that forwards data packets between computer networks, directing traffic on the Internet and ensuring data reaches its destination.

Packet

A formatted unit of data carried by a packet-switched network, which contains both control information and user data.

LAN

A Local Area Network that connects computers and devices within a limited geographical area, such as a home, school, or office.

WAN

A Wide Area Network that covers a large geographical area, connecting multiple local area networks (LANs) and enabling communication over long distances.

Topology

The arrangement of different elements within a network, including how devices are interconnected and how data flows between them. Common types include star, ring, and bus topologies.

Bus topology

A network topology where all devices are connected to a single central cable, known as the bus, allowing data to be transmitted in both directions. This setup is simple and cost-effective but can lead to performance issues if the bus fails.

Star topology

A network topology where all devices are connected to a central hub or switch, allowing for easy management and failure isolation.

Logical topology

Refers to the way data flows within a network, regardless of its physical layout. It defines how devices communicate over the network and can differ from the physical connections.

Physical Toppology

The physical arrangement of devices and cables in a network, showing how they are physically connected. It illustrates the layout and structure of the network components.

WiFi

A technology that allows electronic devices to connect to a network wirelessly using radio waves, enabling internet access without physical cables.

WAP

A Wireless Access Point that allows wireless devices to connect to a wired network using WiFi.

Mesh Topology

A network configuration where each device is connected to multiple other devices, allowing for multiple pathways for data to travel, enhancing reliability and redundancy.

Circuit switching

A method of communication where a dedicated circuit is established for the duration of the transmission, ensuring a constant connection between parties.

Packet switching

A method of data transmission where data is broken into packets and sent over a shared network, allowing for efficient use of bandwidth and flexibility in routing.

Data packet

A formatted unit of data carried by a packet-switched network, consisting of headers and payload. Data packets enable efficient communication by breaking down larger messages into manageable pieces.

Header

The part of a data packet that contains control information, such as source and destination addresses, and protocol information, which is crucial for routing and delivering the packet correctly.

Payload

The part of a data packet that contains the actual message or data being transmitted, excluding headers and metadata.

Checksum

A value used to verify the integrity of data packets by calculating a numerical summary of the packet's contents. If the checksum does not match upon receipt, it indicates potential data corruption.

Cyclical Redundancy Check

A method used to detect errors in data transmission by applying a polynomial division algorithm to the data. It generates a checksum that is sent along with the data, allowing the receiver to check for integrity.

Hop

The act of passing through a network device, such as a router or switch, to reach the destination in a network.

Dijkstra’s Algorithm

A graph search algorithm used to find the shortest path between nodes in a weighted graph, commonly applied in routing and navigation.

Gateway

A network node that serves as an access point to another network, often translating communication protocols between different networks.

MAC address

A unique identifier assigned to a network interface controller (NIC) for communications at the data link layer of a network.

MAC address format

Typically represented as six pairs of hexadecimal digits.

HTTP

An application protocol used for transferring hypertext requests and information on the internet.

TCP/IP

A set of communication protocols used for the internet and similar networks, comprising Transmission Control Protocol (TCP) and Internet Protocol (IP).

Application layer

The topmost layer in the TCP/IP model, responsible for providing network services directly to applications. It enables communication between software applications and the underlying network.

Transport Layer

The layer responsible for end-to-end communication and data transfer between devices over a network, ensuring reliable delivery of messages.

Network Layer

The layer in the TCP/IP model that manages packet forwarding, routing, and addressing between devices across different networks.

Link Layer

The layer responsible for the physical transmission of data over a network, including framing, error detection, and access to the physical medium.

Socket

A combination of an IP address and a port number that enables communication between applications over a network.

Network Interface Card

A hardware component that connects a computer to a network, enabling communication and data transfer.

File Transfer Protocol

A standard network protocol used for transferring files between a client and server over a TCP/IP network.

Mail Server

A computer system that handles the sending, receiving, and storage of email for users, typically using protocols like SMTP, POP3, or IMAP.

POP3

A protocol used by email clients to retrieve emails from a mail server, allowing users to download messages for offline viewing. Once downloaded they are deleted from the server.

IMAP

A protocol used by email clients to access and manage emails on a mail server, allowing users to view and organize messages without downloading them. Unlike POP3, emails remain on the server.

SMTP

A protocol used for sending emails from a client to a mail server or between mail servers, ensuring the delivery of messages over the Internet.

Firewall

A network security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules, acting as a barrier between a trusted internal network and untrusted external networks.

Packet filters

are devices or software that inspect network packets and allow or block them based on specified security rules, often used in firewalls to enhance network security.

Static Filtering

A method of packet filtering where rules are applied to packets based on predetermined criteria, such as source and destination IP addresses and port numbers, without considering the state of the connection.

Port

A communication endpoint used for sending and receiving data in network protocols, identified by a number that specifies a particular service or application on a device.

Proxy Server

A server that acts as an intermediary between a client and another server, forwarding requests and responses to enhance security, performance, and anonymity.

Malware

Malicious software designed to disrupt, damage, or gain unauthorized access to computer systems, often deployed through various means such as email attachments or malicious websites.

Virus

A type of malware that replicates itself by infecting other computer programs or files, often causing harm to systems and data.

Worm

A type of malware that replicates itself to spread to other computers, often exploiting vulnerabilities in software or networks without user intervention.

Trojan

A type of malware that disguises itself as legitimate software to trick users into installing it, allowing unauthorized access to systems.

Passwords

Secret phrases used for authentication to protect access to accounts and systems.

Blagging

The act of manipulating individuals to disclose personal information or access to systems through deception, often using social engineering techniques.

Social Engineering

A manipulation technique that exploits human psychology to gain confidential information or access to systems.

Phishing

A fraudulent attempt to obtain sensitive information, such as usernames and passwords, by disguising as a trustworthy entity in electronic communications.

HTML

A markup language used for creating web pages and web applications, defining the structure and layout of content.

CSS

Cascading Style Sheets, a stylesheet language used to describe the presentation of a document written in HTML or XML.

HTML Tag

An element used in HTML to define the structure and content of a web page, typically enclosed in angle brackets.

Embedded CSS

A method of applying CSS styles directly within an HTML document using the <code><style></code> tag, allowing for specific styling of elements within that page. This method enables customization of styles without external files, making it useful for single-page applications.

Inline CSS

A method of applying CSS styles directly within an HTML element using the "style" attribute, allowing for unique styling of individual elements without needing a separate stylesheet.

External Style Sheet

A separate CSS file linked to an HTML document using the <link> tag, allowing for consistent styling across multiple pages by keeping styles centralized.

Identifier

A name used to identify a specific element in HTML or CSS, allowing for targeted styling or scripting. Identifiers are typically defined using the "id" attribute in HTML.

Selector

A pattern used in CSS to select and apply styles to HTML elements, which can be based on element type, class, ID, or other attributes.

Class

A way to group multiple HTML elements for styling purposes in CSS, defined using the "class" attribute. Classes allow for the application of the same styles to different elements.

Web form

An interactive element on a webpage that allows users to input and submit data, often including fields such as text boxes, checkboxes, and buttons.

Behaviours

The actions or responses that elements on a webpage can exhibit in response to user interactions, often defined through JavaScript or CSS.

JavaScript

A programming language used to create dynamic and interactive content on websites, enabling features like animations, form validations, and user interface enhancements.

Validation

The process of checking user input in a web form to ensure it meets specified criteria before submission, often implemented through JavaScript.

Search Engine

A software system designed to search for information on the World Wide Web, retrieving and indexing data to provide relevant results based on user queries.

Search Engine Indexing

The process of organizing and storing web pages and their content in a search engine's database, enabling efficient retrieval of relevant information in response to user queries.

Key Words

The process of identifying and selecting significant words or phrases that are relevant to a webpage's content, used to improve search engine optimization and indexing.

Meta Tags

HTML tags used to provide structured metadata about a webpage, such as description, keywords, and author, which help search engines understand the page's content.

Description

A brief summary of a webpage's content, typically included in the meta tags, which informs search engines and users about the page's purpose and relevance.

Google PageRank Algorithm

A system used by Google to rank webpages in its search results based on their importance and relevance, determined by analyzing the quantity and quality of links to a page.

Directed Graph

A graph where each edge has a direction, indicating a one-way relationship between nodes, commonly used to represent structures such as networks and workflows. In the context of web technologies, it can represent links between webpages.

Damping Factor

A value used in the PageRank algorithm to account for the probability that a user will continue clicking on links rather than stopping, ensuring that all pages receive some rank even if they are not linked to.

Client-server network

A network architecture where client devices request resources or services from centralized servers, which provide the requested data or functionality. This model is fundamental in web technologies for enabling communication and resource sharing.

Client

A device or application that accesses services or resources provided by a server in a client-server network architecture, often used to request data or perform tasks.

Server

A computer or system that provides resources, data, or services to other computers, known as clients, over a network.

Cloud Computing

A model that enables on-demand access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications) over the internet, allowing for scalable and flexible resource management.

SaaS

Software as a Service, a cloud computing model that delivers software applications over the internet on a subscription basis, allowing users to access and use them without installation.

Peer-to-Peer network

A decentralized network architecture where each participant, or peer, can act as both a client and a server, sharing resources directly with one another without a central server.

Client-side processing

Refers to operations performed by a client device, such as a web browser, where data is processed locally rather than on a server. This allows for faster response times and reduced server load.

Server-side processing

Refers to operations performed on a server, where data is processed before being sent to the client. This approach allows for centralized control and can handle complex computations or database interactions.

API

A set of rules and protocols for building and interacting with software applications, allowing different programs to communicate with each other.

Thin-client computing

A network architecture where most processing occurs on a server, with minimal processing done on the client device. This setup reduces resource requirements on client machines and centralizes data management.

Thick-client computing

A network architecture where the client device performs significant processing and storage tasks, reducing the load on the server. This allows for richer user experiences and local data management.