Computer Networks Task 1, Assignments of Computer science

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UNIT 4:

INTRODUCTION

TO COMPUTER

NETWORKS

TYPES OF NETWORKS

Local Area Network (LAN) Covers a small geographical area such as a building, room or school site. It allows users within one location to share files, resources, printers, and communicate easily. It can be used at schools, offices, computer labs, homes... Wide Area Network (WAN) Connects multiple LANs across large distances. It uses public infrastructure (like telephone lines or satellites). It enables communication between different geographic locations. Mostly used in Global companies, banks, universities with multiple campuses... Personal Area Network (PAN) A very small network centred around a single person and their devices. Enabling fast, wireless, short- range communication between personal gadgets. It can be used to create individual workspaces Virtual Private Network (VPN) Creates an encrypted connection across the internet, making remote connections secure. It allows remote employees to safely access internal company systems. Mainly used in remote work, travel or business networks. Storage Area Network (SAN) A high-speed network that connects storage devices to servers. It improves data storage performance, backup and retrieval. Used by data centres, large enterprises...

PHYSICAL TOPOLOGIES

• Tree topology is when devices

are connected hierarchically. It

is scalable, easy to grow and

can match organisational

structures. However if the main

backbone fails, large segments

lose connection. It can be used

in university campus networks.

• Ad-Hoc topology is when devices connect wirelessly without infrastructure. It is quick setup and useful in emergencies or temporary setups. However it has a weak security and is not stable for large networks. It can be used for sharing files between phones or laptops on the fly.

METHODS OF CONNECTING DEVICES Ethernet Connection Wired connection using copper or fibre cables. Can be use in offices, gaming or servers in general. It is fast, stable, secure and has a low latency. How ever it requires physical cables and ports. Wi-Fi Connection Wireless connection using radio signals. Mostly used in homes, schools and different public spaces. It is flexible, easy to access and multiple devices can be supported. However it is sensitive to Interference, slower than Ethernet and has higher security risks Bluetooth Connection Short-range wireless connection technology. Maily used in wearables (headphones, smart watches...) It used low power and is simple for pairing. However it has a very short range and slow speeds. 3G/4G/5G Connection Mobile cellular networks connection used mainly in smartphones and some IoT devices. It works anywhere with mobile signal and has a wide coverage. However it is usually submitted to data limits and is dependent on signal strength.

PROTOCOLS AND STANDARDS OSI Model: The Open Systems Interconnection model is a conceptual framework that divides network communications functions into seven layers explaining how network communication happens. It standardises how devices communicate and ensures compatibility.

TCP/IP: The core of the

internet protocol suite

(Transmission Control Protocol

/ Internet Protocol), it ensures

reliable and routable

communication between

devices.

Ethernet Standards: a set of protocols and guidelines that dictate how data is transmitted over a network. They ensure interoperability between devices from different manufacturers by defining aspects such as speed (10Mbps,1Gbps, 10Gbps), cabling, and signalling.

HARDWARE COMPONENTS

Component Function Example Use Server Stores data, applications and manages network services. File servers, email servers, web servers. Router Directs traffic between networks; often connects to the internet. Home router connecting LAN to Internet Service Provider Switch Connects devices on a LAN and routes data intelligently Office devices (printers, computers...) connected through a switch. Hub Basic device that broadcasts data to all devices. Small temporary networks (considered obsolete). Cables Physical medium that carries data (Ethernet/Fibre). Cat6 (Category 6) Ethernet connecting a PC to a switch. Nodes Any device on a network. Phones, PCs, printers. Network Interface Card (NIC) Allows device to connect to a network (wired or wireless). Laptop Wi-Fi card or PC Ethernet card. 8

PURPOSE, ROLE, AND BENEFITS OF NETWORKS IN ORGANISATIONS. Communication and accessing information (internal and external to the organisation):

• Networks allow staff to communicate with each other or with clients quickly using email, instant messaging, video calls or voice over IP (VOIP)
• Enables communication across different buildings, locations or even countries.
• Allows shared access to files, documents, and databases.
• Tools like Microsoft Teams, Zoom, and Slack rely on network connections to function.

PURPOSE, ROLE, AND BENEFITS OF NETWORKS IN ORGANISATIONS. Supporting business processes:

• The use of different management software requires networks such as payroll, sales systems, customer management, inventory control...
• Allows automation increasing efficiency and decreasing human error.
• Allows consistency and accuracy in running operations.
• Staff can access resources from any connected device within the organisation.

PURPOSE, ROLE, AND BENEFITS OF NETWORKS IN ORGANISATIONS. Collaboration:

• Networks allow multiple users to work on the same files or projects at the same time.
• Supports remote working and hybrid working environments.
• Improves productivity by enabling real-time teamwork. Entertainment:
  • Some organisations use networks for media streaming, digital signage, or customer engagement.
  • Used in shops, restaurants, waiting rooms, classrooms, or promotional displays.
  • Enhances user experience and can help organisations communicate messages visually.

SECURITY THREATS EFFECT AND

SOLUTIONS

Threat Type Effect Solution Internal Threats (accidental or deliberate actions by staff)

• Accidental deletion of files
• Misuse of data
• Insider sabotage
• Unauthorised access to confidential information
  • Staff training
  • Role-based access control
  • Monitoring user activity
  • Strong policies and consequences External Threats (hackers, cybercriminals)
• Data theft
• System breaches
• Financial loss
• Service disruption
• Firewalls
• Intrusion detection systems (IDS)
• Strong passwords and multi-factor authentication
• Regular system updates Physical Threats (fire, theft, flooding, vandalism)
• Damage to network hardware
• Permanent loss of equipment and data
• Long downtime and expensive repairs
• CCTV and security locks
• Backup systems and off-site storage
• Fire suppression systems
• Environmental controls Social Engineering (phishing, vishing, smishing, tailgating)
• Employees tricked into giving passwords or sensitive information
• Attacker gains physical or digital access
• Major data breaches
• Staff cybersecurity training
• Email filtering tools
• Identity checks for visitors
• Strong anti-phishing protocols

SECURITY MEASURES

User IDs and Passwords Control access by ensuring only authorised users can log into systems. Can be very effective when using strong password policies, multi-factor authentication, and regular password changes, but weak if passwords are simple or shared. Encryption Converts data into unreadable code so that only authorised users can access it. It is highly effective for protecting sensitive files and communication. Even if data is intercepted or stolen, it is useless without the decryption key. Note that it is essential for GDPR compliance certification. For example well-known standard that is used for large data files is ASE Anti-virus / Anti-malware Such as Norton and Bitdefender detect, block, and remove malicious threats such as viruses, trojans, and ransomware. Can prevent most common malware infections. However it is not effective if outdated or if users bypass warnings. Firewalls Such as Fortinet FortiGate monitor and filter incoming/outgoing network traffic to block harmful connections. It is an extremely effective first line of defence as it protects internal systems by blocking suspicious traffic. However it Needs to be properly configured and regularly updated. Access Control (Permissions & User Roles) Restricts who can view, edit, or delete files, applications, and resources. Highly effective for reducing insider threats. Protects sensitive data by ensuring only authorised staff access it. However it needs to be properly managed.

SECURITY MEASURES

Web & Wireless Security (WPA3, HTTPS) Protects Wi-Fi and online communication from interception and unauthorised access. Strong encryption (WPA3) makes Wi-Fi secure. HTTPS protects web traffic. However it is weak if old passwords or outdated protocols are used. Patch Management Keeps software and systems up to date to close security vulnerabilities. It is critical for preventing attacks that exploit outdated or unpatched software but only if updates are installed frequently and consistently across all devices. Training & Risk Awareness Educates staff on recognising threats such as phishing, social engineering, and unsafe practices. It is considered one of the most effective defences because human error causes many breaches as regular training greatly reduces risk from phishing and scams. IT Security Policies & Procedures Establish rules for safe use of devices, networks, and data within an organisation. Very effective when enforced properly as it ensures consistent protection and reduces risky behaviour. Less effective if policies are ignored or not reviewed.