Topologies, servers, networking models and segmentation
Design a network from topology, server, model and segmentation choices rather than treating each concept in isolation.
Architecture is a set of trade-offs
- describe star, mesh and hybrid topologies using reliability, transmission speed, scalability, data collisions and cost;
- describe DNS, DHCP, file, mail, proxy and web servers with function, scalability, reliability and security;
- compare client-server and peer-to-peer models in real applications;
- explain segmenting, subnetting and VLANs for performance, congestion control, resource management and security.
Rapid Recall Deck
Attempt each card first. If a term is new, flip and study it, then answer it again without looking. Mark only secure recall as “Know it”.
Use all five required factors
Compare three topologies
A college campus needs a network that can grow, remain usable after some link failures and stay within budget.
Star: easy to expand and centrally manage; individual link failures usually affect one device, but the central device is important and cabling/equipment add cost. Mesh: multiple paths can provide high resilience, but many links increase installation/management cost and complexity. Hybrid: combines structures so critical areas can gain redundancy while other areas use cheaper star-style access. A campus often benefits from a hybrid design because requirements vary across buildings/segments.
Server function must survive realistic demand and threats
DNS + DHCP
DNS: name resolution. DHCP: client network configuration/address assignment.
File + mail
File server: shared file storage/access. Mail server: email sending/receiving/storage services.
Proxy + web
Proxy: intermediary for client requests, enabling filtering/caching/access control. Web server: serves web resources/services to clients.
Function, scalability, reliability and security
Server architecture decision
A school expects 1,500 users to access shared files and web resources. Describe three design concerns beyond simply choosing a file server and web server.
The system needs enough capacity to scale with simultaneous users/data. Reliability may require backups, redundancy and recovery plans so one failure does not remove the service. Security requires authentication/authorization, secure configuration, patching and network protections so users only access permitted resources.
The application determines whether centralization is a strength
Client-server vs peer-to-peer
Compare and contrast client-server and peer-to-peer networking for (A) online banking and (B) decentralized file sharing. Include at least one similarity or shared purpose, key differences in control/security/infrastructure, and a scenario-based judgement.
Online banking: client-server is appropriate because the organization needs central control, authoritative records, authentication, auditing and managed security/reliability. Decentralized file sharing: peer-to-peer can distribute storage/bandwidth across peers and avoid dependence on one central server, but consistency, trust, availability and security are harder to manage. Neither model is universally better.
Segmentation can improve performance and security at the same time
Segmenting
Divide a larger network into smaller logical/physical sections to reduce unnecessary traffic, isolate faults/threats and manage resources.
Subnetting
Divide an IP network into smaller address/routing domains, helping control broadcast scope, organization and routing/resource use.
VLAN
Create logical local-network groups independent of physical switch location, allowing departments/device classes to be separated for management/performance/security.
Segmentation is useful because policy follows network boundaries
Explain a segmentation plan
Students, staff, finance systems and guest Wi-Fi currently share one flat campus network. Large student file transfers create congestion, and guest devices must never reach finance systems. Propose a segmentation plan using network segments, VLANs and IP subnets. Explain how the plan improves both traffic management and security.
Create separate network segments/VLANs for students, staff, finance and guests, with distinct IP subnets and controlled routing/firewall rules between them. Broadcast/local traffic stays more contained, reducing congestion and simplifying resource management. Guest/student devices can be prevented from reaching sensitive finance systems while permitted services remain routable between segments.
Architecture answers need explicit factors and application
Paper 1-style mini-set
1. Describe one reliability advantage and one cost disadvantage of mesh topology.
2. Describe the function of a DNS server.
3. Compare client-server and peer-to-peer for one real-world application.
4. Explain how a VLAN can improve network security.
- Multiple paths can keep communication available after a link failure; extra links/equipment increase cost/complexity.
- DNS resolves domain names to the addressing information required to locate the requested network host/service.
- A valid comparison should contrast centralized management/security/reliability with peer distribution/no dedicated central server, then link the judgement to the chosen application.
- A VLAN logically separates device groups so traffic/access between groups can be controlled, reducing exposure of sensitive systems even when devices share physical switching infrastructure.
Finish the learning cycle
IA — main task
Continue IA Criterion E/final-submission work according to your schedule. Evaluate against success criteria rather than only describing features.
Paper 1 — short practice
From memory, reproduce all topology factors, six server types, client-server vs peer-to-peer and the three segmentation concepts.