Networking and Internet Concepts

UNIT 5: COMMUNICATION AND THE INTERNET

Assessment Objectives

  • Objective 1: Demonstrate knowledge and understanding of the key principles of computer science.

  • Objective 2: Apply knowledge and understanding of key concepts and principles of computer science.

  • Objective 3: Analyse problems in computational terms:

    • Make reasoned judgements.

    • Design, program, test, evaluate, and refine solutions.

Learning Outcomes

  • Understanding different types of networks and their importance.

  • Recognizing security threats to data and implementing protection strategies.

  • Exploring the Internet as a massive network with specific hardware and software requirements.

NETWORKS
Definition

  • Network: An arrangement of computers and devices connected to share resources and data.

Key Vocabularies

  • Network Service: An app running on a server providing operations such as data storage, printing, or communications.

Why Use Networks?

  • Support multiple users accessing multiple services simultaneously.

  • Share resources and facilitate communication (e.g., email, video chat).

Types of Networks

  1. Local Area Network (LAN): Covers a small area (e.g., home, school).

  2. Wide Area Network (WAN): Covers a large area connecting multiple LANs (e.g., the Internet).

  3. Personal Area Network (PAN): For short-range communication between devices (e.g., Bluetooth).

  4. Wireless Local Area Network (WLAN): Wi-Fi-based LAN with high-frequency radio communication.

NETWORK TOPOLOGIES
Definitions

  • Topology: Arrangement of devices on a network.

Main Topologies

  1. Bus: Single cable with terminators.

    • Advantages: Cost-effective; easy to add devices.

    • Disadvantages: Entire network fails if cable is damaged; difficult fault detection.

  2. Ring: Devices connected in a closed loop.

    • Advantages: No data collision.

    • Disadvantages: Failure of one device affects the entire network.

  3. Star: All devices connected to a central hub.

    • Advantages: Easy to manage faults; additional devices can be added without interruptions.

    • Disadvantages: Central hub failure results in network failure; high implementation costs.

  4. Mesh: Devices interconnected, either fully or partially.

    • Advantages: Very fault-tolerant.

    • Disadvantages: Complex and expensive to install and manage.

NETWORK PROTOCOLS
What is a Protocol?

  • Set of rules governing the format and transmission of data over a network.

Main Types of Protocols

  1. TCP/IP: Protocol stack facilitating data transmission.

  2. HTTP/HTTPS: Protocols for web data transmission, with HTTPS offering secure communication.

  3. FTP: Used for transferring files.

  4. Email Protocols: SMTP (sending), POP3, and IMAP (retrieval).

DATA TRANSMISSION

  • Data transmitted in packets containing sender/receiver addresses and order information.

  • Bandwidth: The amount of data transmitted over time.

  • Latency: The delay in data transmission.

NETWORK SECURITY
Importance

  • To protect data from unauthorized access, ensuring confidentiality, integrity, and availability.

Security Threats

  1. Malware: Malicious software designed to disrupt or gain unauthorized access.

  2. Phishing: Attempts to extract sensitive data by deception.

  3. Eavesdropping: Unauthorized interception of data transmission.

Protection Strategies

  1. Authentication: Verifying user identity.

  2. Access Control: Restricting user access to resources.

  3. Firewalls: Monitoring and controlling incoming/outgoing traffic based on predetermined security rules.

  4. Encryption: Securing data to prevent unauthorized access.

THE INTERNET
Definition

  • A worldwide system of interconnected networks using TCP/IP protocol.

IP Addressing

  • IPv4: Composed of four decimal numbers separated by dots.

  • IPv6: Longer address format to accommodate more devices.

SUMMARY

  • Networks enhance communication and resource sharing.

  • Understanding protocols and security is crucial for maintaining network integrity.

  • The Internet is fundamentally a vast WAN supporting a multitude of applications via TCP/IP.

Assessment Objectives

  • Objective 1: Demonstrate in-depth knowledge and understanding of the fundamental principles of computer science, including hardware, software, data structures, algorithms, and their applications.

  • Objective 2: Apply knowledge and understanding of key concepts and principles of computer science to solve real-world problems, focusing on efficiency, scalability, and user experience.

  • Objective 3: Analyse complex problems in computational terms by making reasoned judgments based on logical reasoning, creativity, and innovation; design, program, rigorously test, evaluate, and refine solutions systematically.

Learning Outcomes

  • Acquire a thorough understanding of different types of networks, their architecture, functionalities, and real-world applications, emphasizing their importance in communication.

  • Recognize various security threats to data integrity, confidentiality, and availability and implement robust protection strategies to mitigate risks effectively.

  • Explore the Internet as a vast, decentralized network with specific hardware requirements (such as routers, switches, and legacy systems) and software frameworks, alongside the protocols that facilitate communication across devices globally.

NETWORKS

Definition

  • Network: An arrangement of interconnected computers, servers, and devices designed to share resources, information, and data effectively and efficiently across geographical locations.

Key Vocabularies

  • Network Service: An application hosted on a server that facilitates operations such as data storage, file-sharing, printing devices, or communication between users via protocols such as HTTP or FTP.

Why Use Networks?

  • Enable multiple users to access shared resources simultaneously, increasing productivity and collaboration.

  • Facilitate seamless communication between users through various channels such as email, video chat, and messaging services, enhancing teamwork and connectivity.

Types of Networks

  1. Local Area Network (LAN): Typically covers a small geographical area like a home, office, or school; provides high-speed connections and low latency for users in close proximity.

  2. Wide Area Network (WAN): Spans extensive distances, connecting multiple LANs across cities or countries, exemplified by the Internet's structure, enabling broad access to resources and information.

  3. Personal Area Network (PAN): A small network, often used for short-range communication, facilitating connections between personal devices such as smartphones, tablets, and laptops via technologies like Bluetooth.

  4. Wireless Local Area Network (WLAN): A LAN that utilizes high-frequency radio waves (Wi-Fi) to allow devices to connect without physical cables, enhancing mobility and flexibility in accessing network resources.

NETWORK TOPOLOGIES

Definitions

  • Topology: The geometric arrangement and organizational structure of devices and connections on a network, affecting performance and reliability.

Main Topologies

  1. Bus: A single central cable (the bus), with terminators at both ends.

    • Advantages: Cost-effective construction; facilitates easy addition of devices without significant layout change.

    • Disadvantages: A single point of failure; if the cable is broken, the entire network becomes inoperable and fault detection can be challenging.

  2. Ring: Devices are connected in a closed loop, where data travels in one direction.

    • Advantages: Eliminates data collisions due to the defined transmission order.

    • Disadvantages: A malfunction in any single device or cable can disrupt the network for all users.

  3. Star: All devices are connected to a central hub or switch, creating a star-like structure.

    • Advantages: Centralized management simplifies fault diagnosis; devices can be added or removed without disrupting network operation.

    • Disadvantages: The central hub represents a single point of failure; high installation and maintenance costs involved.

  4. Mesh: Devices are interconnected in multiple pathways creating robustness.

    • Advantages: Highly fault-tolerant; failure of one link does not affect the overall network connectivity.

    • Disadvantages: Complex setup and maintenance due to the number of connections; can become costly based on the degree of interconnection chosen.

NETWORK PROTOCOLS

What is a Protocol?

  • A set of established rules that dictate how data is formatted, transmitted, and received across a network, covering aspects such as error handling, data integrity, and the timing of data transmission.

Main Types of Protocols

  1. TCP/IP: A foundational suite of protocols including Transmission Control Protocol (TCP) and Internet Protocol (IP), essential for establishing reliable communication between devices on a network.

  2. HTTP/HTTPS: HyperText Transfer Protocol (HTTP) is used for transmitting web pages, while HTTPS adds a layer of security through SSL/TLS encryption for secure web transactions.

  3. FTP: File Transfer Protocol is used for transferring files between a client and a server, allowing for uploads and downloads with various command options.

  4. Email Protocols: Protocols like SMTP (Simple Mail Transfer Protocol) for sending emails and POP3 (Post Office Protocol) or IMAP (Internet Message Access Protocol) for retrieving emails, facilitating efficient electronic communication.

DATA TRANSMISSION

  • Data is transmitted in structured packets that contain information about sender/receiver addresses, sequencing, and error-checking codes to ensure accurate delivery.

  • Bandwidth: Refers to the maximum rate at which data can be transferred over a network connection in a specified time, typically shown in bits per second (bps).

  • Latency: The delay noticed from the time a data packet is sent to the time it is received, impacting the responsiveness of a network, particularly in real-time applications.

NETWORK SECURITY

Importance

  • To establish protective measures against unauthorized access to data and systems, ensuring confidentiality, integrity, and availability of information.

Security Threats

  1. Malware: Malicious software designed to infiltrate and disrupt systems, steal data, or gain unauthorized access, including viruses, worms, and ransomware.

  2. Phishing: A deceptive attempt to acquire sensitive information, such as login credentials or financial data, often through spoofed emails or fraudulent websites.

  3. Eavesdropping: The unauthorized interception of data being sent over a network, allowing attackers to collect sensitive information during transmission.

Protection Strategies

  1. Authentication: Implementing methods such as passwords, biometrics, and two-factor authentication to verify user identities before granting access.

  2. Access Control: Utilizing permissions and user roles to restrict access to sensitive resources and information based on organizational policies.

  3. Firewalls: Hardware or software solutions that monitor and control incoming and outgoing traffic according to predetermined security rules, preventing unauthorized access.

  4. Encryption: Techniques that encode data to secure it against unauthorized access, ensuring that even if intercepted, the information remains unreadable without decryption keys.

THE INTERNET

Definition

  • A global system of interconnected networks using the TCP/IP suite of protocols, enabling the exchange of information and communication amongst billions of devices across various platforms.

IP Addressing

  • IPv4: An addressing method utilizing a 32-bit format composed of four decimal numbers (e.g., 192.168.1.1), the most common IP addressing scheme.

  • IPv6: An extension to IPv4, employing a 128-bit format allowing a vastly larger number of unique IP addresses, essential for accommodating the growing number of internet-connected devices.

SUMMARY

  • Networks enhance communication and resource sharing through established protocols and topologies.

  • An in-depth understanding of network protocols, security measures, and data transmission principles is crucial for maintaining network integrity and reliable operation.

  • The Internet is fundamentally structured as a vast WAN supporting a multitude of applications, services, and protocols that ensure continuous global connectivity and