IB Computer Science HL · Year 2 · Lesson 40

Topologies, servers, network models and segmentation

Network architecture determines how devices, servers, segments and topologies are organized and how that affects performance and control.

Paper 150 minutesA2.2.1 · A2.2.2 · A2.2.3 · A2.2.4
Use Next or the arrow keys.
Course homeIA hub2027 case study
Today’s targets

What you need to be able to do

2 / 9
  • DescribeThe functions and practical applications of network topologies
  • DescribeThe function of servers
  • Compare + contrastAnd contrast networking models
  • ExplainThe concepts and applications of network segmentation
A2.2.1A2.2.2A2.2.3A2.2.4
Paper 1 lensMatch the depth of every response to the command term. Previously learned content can move quickly, but retrieval must still be accurate.
Page 2 of 9
Retrieve

Rapid Recall Deck

3 / 9

Say the answer aloud before flipping. Mark secure knowledge quickly and spend time on the gaps.

  • What characterizes a star topology?: Devices connect to a central device; this simplifies management but makes the central device a critical point of failure.
  • What characterizes a mesh topology?: Devices have multiple interconnections, improving redundancy and route options at the cost of more links, equipment, and complexity.
  • What is a hybrid topology?: A network that combines features of more than one topology to meet practical requirements.
  • Which factors should be compared when choosing a network topology?: Reliability, transmission speed, scalability, data collisions, and cost.
  • What are the main server types in this topic?: DNS, DHCP, file, mail, proxy, and web servers.
  • What is the difference between client-server and peer-to-peer networking?: Client-server centralizes services on dedicated servers; peer-to-peer allows devices to provide resources directly to one another.
  • Why segment a network?: To improve performance and security, reduce congestion, and manage resources by separating traffic into smaller logical or physical sections.
  • How are subnetting and VLANs used in segmentation?: Subnetting divides IP networks into smaller address/routing groups; VLANs create logical LAN segments on shared switching infrastructure.
Page 3 of 9
A2.2.1 + A2.2.2 · Learn

Core knowledge and application

4 / 9
A2.2.1Describe

The functions and practical applications of network topologies

Network architecture determines how devices, servers, segments and topologies are organized and how that affects performance and control.

Exam moveGive a detailed, accurate account of what happens or what something is like.
Required detail 1Network topologies: star, mesh, hybrid
Required detail 2Factors to consider must include reliability, transmission speed, scalability, data collisions, cost
Required detail 3Examples may include home and small office settings, where reliability is paramount, and the use of networks in larger settings (e.g. corporations, government departments, college campuses)

Explain it without notes

Describe: The functions and practical applications of network topologies in the context of a campus network being redesigned for performance and management.

  • Network topologies: star, mesh, hybrid
  • Factors to consider must include reliability, transmission speed, scalability, data collisions, cost
  • Examples may include home and small office settings, where reliability is paramount, and the use of networks in larger settings (e.g. corporations, government departments, college campuses)
A2.2.2Describe

The function of servers

Network architecture determines how devices, servers, segments and topologies are organized and how that affects performance and control.

Exam moveGive a detailed, accurate account of what happens or what something is like.
Required detail 1Types of servers: domain name server (DNS), dynamic host configuration protocol (DHCP), file server, mail server, proxy server, web server
Required detail 2Factors to consider must include function, scalability, reliability and security

Explain it without notes

Describe: The function of servers in the context of a campus network being redesigned for performance and management.

  • Types of servers: domain name server (DNS), dynamic host configuration protocol (DHCP), file server, mail server, proxy server, web server
  • Factors to consider must include function, scalability, reliability and security
Page 4 of 9
A2.2.3 + A2.2.4 · Learn

Core knowledge and application

5 / 9
A2.2.3Compare + contrast

And contrast networking models

Network architecture determines how devices, servers, segments and topologies are organized and how that affects performance and control.

Exam moveMake direct, paired comparisons using the same criteria.
Required detail 1Client-server and peer-to-peer models
Required detail 2The respective benefits and drawbacks of client-server and peer-to-peer models
Required detail 3Real-world applications may include web browsing, email services, online banking, file sharing, VoIP services, blockchain

Explain it without notes

Compare + contrast: And contrast networking models in the context of a campus network being redesigned for performance and management.

  • Client-server and peer-to-peer models
  • The respective benefits and drawbacks of client-server and peer-to-peer models
  • Real-world applications may include web browsing, email services, online banking, file sharing, VoIP services, blockchain
A2.2.4Explain

The concepts and applications of network segmentation

Network architecture determines how devices, servers, segments and topologies are organized and how that affects performance and control.

Exam moveGive the mechanism or relationship and make the reasons/causes explicit.
Required detail 1Segmentation for network performance and security, to reduce congestion, to manage network resources efficiently
Required detail 2Network segmentation must include the uses and roles of segmenting, subnetting and virtual local area networks (VLANs)

Explain it without notes

Explain: The concepts and applications of network segmentation in the context of a campus network being redesigned for performance and management.

  • Segmentation for network performance and security, to reduce congestion, to manage network resources efficiently
  • Network segmentation must include the uses and roles of segmenting, subnetting and virtual local area networks (VLANs)
Page 5 of 9
Worked model · A2.2.1–A2.2.4

Topology, server and segmentation decisions

6 / 9
Star Mesh Hybrid
Factor
Star
Mesh
Reliability
central device is critical
multiple alternative paths
Cost/complexity
moderate
high as links increase
Scalability
usually straightforward
full mesh becomes expensive

Servers

DNS resolves names; DHCP supplies configuration; file/mail/web servers provide specific services; a proxy mediates requests. Evaluate function, scalability, reliability and security.

Segmentation

Segments/subnets/VLANs reduce broadcast/congestion domains, organize resources and can improve security by separating traffic and applying different policies.

Model choiceCompare client–server with peer-to-peer for online banking versus ad-hoc file sharing. Use control, reliability, scalability and security as paired criteria.
Page 6 of 9
Apply

Transfer to a new scenario

7 / 9
ScenarioA campus network being redesigned for performance and management needs a design or technical decision related to today’s topic. Explain what matters and why.
  • Network topologies: star, mesh, hybrid
  • Factors to consider must include reliability, transmission speed, scalability, data collisions, cost
  • Types of servers: domain name server (DNS), dynamic host configuration protocol (DHCP), file server, mail server, proxy server, web server
  • Factors to consider must include function, scalability, reliability and security
  • Client-server and peer-to-peer models
  • The respective benefits and drawbacks of client-server and peer-to-peer models
  • Segmentation for network performance and security, to reduce congestion, to manage network resources efficiently
Page 7 of 9
Exam lens

Paper 1 practice

8 / 9
Build the response before checking notesUse precise terminology and match the required depth.
  1. Describe: The functions and practical applications of network topologies in the context of a campus network being redesigned for performance and management.
  2. Describe: The function of servers in the context of a campus network being redesigned for performance and management.
  3. Compare + contrast: And contrast networking models in the context of a campus network being redesigned for performance and management.
Self-checkAnswer the exact command term. For explain, include mechanism/reason; for compare, pair criteria; for discuss/evaluate/justify, build supported reasoning and a conclusion.
Page 8 of 9
Homework

Finish the learning cycle

9 / 9

IA — main task

Complete Criterion E and final IA quality checks. Evaluate the product against success criteria and propose specific, feasible improvements.

Syllabus — short

Complete a short Paper 1 retrieval task; keep the IA as the main workload.

Designed by David Xu
© 2026 David Xu. All rights reserved.
Educators and students are welcome to use these materials for non-commercial teaching and learning with attribution. Please share the original link when possible. Reposting, redistributing modified copies, removing attribution, or commercial use requires prior permission.
End of Lesson 40.