week 30

K1.30 The fundamentals of network topologies and network referencing models and the application of cyber security principles:

Fundamentals of Network Topologies

A network topology describes how devices (nodes) are connected and how data travels through the network.

Topology Description Advantages Disadvantages Example
Bus All devices share a single backbone cable. Cheap, easy to install. A single cable fault can bring down the network, data collisions. Early small office networks.
Star Devices connect to a central hub or switch. Easy to add/remove devices, centralised management. If the hub fails, the network goes down. Most modern LANs.
Ring Each device connects to two others, forming a circle. Data flows in one direction, reduced collisions. A fault in one device can break the whole network. Older token ring networks.
Token Ring A special type of ring where a “token” controls access. Prevents data collisions. Outdated, expensive to maintain. Legacy corporate systems.
Mesh Every device connects to every other device. Very resilient, multiple paths for data. Very costly, complex cabling. Military or critical networks.
Hybrid Combines two or more topologies. Flexible, scalable. Can be expensive and complex. Large organisations combining star and mesh.
Client‑Server Clients (e.g. user devices) request services from a central server. Centralised management, easier backups. Server failure affects all clients. Websites, school networks.
Peer‑to‑Peer (P2P) Devices act as both client and server. Cheap, easy to set up. Harder to secure, no central control. File‑sharing between home PCs.

 

Network Referencing Models

These models explain how data travels through network layers.

OSI Model (7 Layers)

Layer Purpose Example
Application End‑user applications Email client, web browser
Presentation Data formatting/encryption SSL/TLS encryption
Session Establish/maintain sessions Session tokens, logins
Transport Reliable delivery, error checking TCP, UDP
Network Addressing, routing IP addressing, routing tables
Data Link Node‑to‑node transfer Ethernet frames
Physical Hardware transmission Cables, switches

 

TCP/IP Model (4 Layers)

Layer Purpose Example
Application Interfaces for end‑user processes HTTP, FTP
Transport Manages communication and reliability TCP, UDP
Network Logical addressing and routing IP addressing
Network Interface Physical delivery of data Ethernet, Wi‑Fi

 

Comparison:
The TCP/IP model is simpler (4 layers) and more widely used today, while the OSI model is more detailed (7 layers) and is often used as a teaching reference.

 

Applying Cyber Security Principles to Network Architecture

Modern network design must include minimum cyber security standards to protect users, systems and data.
These are based on five key principles:

Identify

Manage risks to network security, users and devices.

  • Assign a cyber security lead.

  • Perform risk assessments to find vulnerabilities.

  • Document configurations and responses to threats.

Example:
An IT team maintains a configuration log for all routers and performs regular threat assessments.

Protect

Apply controls to minimise potential risks.

  • Implement anti‑virus software and firewalls.

  • Reduce the attack surface (disable unused services/ports).

  • Use trusted, supported operating systems.

  • Decommission old, vulnerable systems.

  • Carry out regular security audits.

  • Encrypt data at rest and in transit.

  • Assign minimum access (least privilege).

  • Provide staff with cyber security training.

Example:
All staff accounts use multi‑factor authentication and only have access to resources relevant to their role.

Detect

Identify security issues quickly.

  • Apply monitoring tools and procedures.

  • Review audit logs and event logs.

  • Monitor network activity for anomalies.

Example:
A company uses an IDS (Intrusion Detection System) to alert admins to unusual network traffic.

Respond

React to contain and minimise the impact of incidents.

  • Have a defined incident response plan.

  • Contain the threat, isolate affected systems.

Example:
If ransomware is detected, the affected server is immediately taken offline to stop spread.

Recover

Restore systems and data and improve for the future.

  • Maintain up‑to‑date backups.

  • Document and review incidents for lessons learned.

Example:
After a cyber attack, IT restores files from cloud backups and updates their policies to prevent recurrence.

 

One Vision
Scenario: You are designing a secure network for a small organisation.

Task:
1. Choose one topology (e.g. star) and explain why it suits the business.
2. Map the network using either the OSI or TCP/IP model.
3. Apply the five cyber security principles (identify, protect, detect, respond, recover) to your chosen topology and justify each step.

Extension:
Draw a labelled diagram showing:

  - Your chosen topology
  - Where you would implement firewalls, IDS/IPS, and access controls.

 


Last Updated
2025-07-15 10:57:38
English and Maths

English


Maths


Stretch and Challenge

Stretch and Challenge


  • Fast to implement
  • Accessible by default
  • No dependencies
Homework

Homework


Equality and Diversity Calendar
How to's

How 2's Coverage




Links to Learning Outcomes

Links to Assessment criteria
 

Files that support this week

| | | | |
Week 29←
PrevWeek 30←
PrevWeek 31←
Prev→
Next