Chapter 34 — Comparative project | Bachelor's Network and communications security

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Chapter 34 — Comparative project

Lesson map

Lesson 34 published. Map, example, EX100.

flowchart TD
  N0["Learning outcomes"]
  N1["34.1 Options for the clinics"]
  N2["34.2 Criteria and weights"]
  N3["34.3 Sensitivity"]
  N4["34.4 Justifying the choice"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5
  N5 --> EX["Worked example"]
  EX --> Q["Exercise EX100"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["34.1 Options for the clinics"]
  N2["34.2 Criteria and weights"]
  N3["34.3 Sensitivity"]
  N4["34.4 Justifying the choice"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> Q["EX100"]

[Learning outcomes]
    |
    v
[34.1 Options for the clinics]
    |
    v
[34.2 Criteria and weights]
    |
    v
[34.3 Sensitivity]
    |
    v
[34.4 Justifying the choice]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX100]

Learning outcomes

You will (1) compare design options systematically; (2) use criteria and weights; (3) justify a choice.

34.1 Options for the clinics

Priya compares three ways to separate clinic groups. Option A uses separate wireless networks and virtual LANs with access control lists on existing switches, at low cost but with limited logging. Option B adds a small firewall at each clinic, giving stateful filtering, logging and VPN support. Option C sends all traffic to a cloud-delivered security service, which reduces on-site equipment but depends on internet links and a subscription. Each option could work; the question is which fits the clinics best.

34.2 Criteria and weights

She chooses criteria that matter to the clinics: risk reduction, cost over five years, ease of operation for one part-time IT lead, resilience when the internet link fails, and quality of logging. Managers weight risk reduction and ease of operation highest. Each option is scored from one to five on each criterion. The weighted totals put option B first, option C second and option A third, mainly because option A's limited logging fails the detection needs identified earlier. The weights are agreed with managers before any scoring is done.

34.3 Sensitivity

Priya tests whether the result depends on the weights. If cost is weighted much higher, option A moves level with B; if internet resilience is weighted lower, option C nearly matches B. She presents these sensitivities to managers so they understand the choice depends on their priorities. Making the decision's dependence on values visible prevents analysis from appearing more objective than it is, and lets managers own the choice rather than simply accepting a number. She shows the sensitivity results as a small table with each changed weight and the resulting order of options.

34.4 Justifying the choice

The clinics choose option B. Priya writes a decision record explaining the options, scores, sensitivities and reasons, noting that option C may become attractive later if internet links become more reliable and the clinics grow. The record helps future staff understand why the design looks as it does and when to revisit it. Comparative analysis does not guarantee the best choice, but it makes the reasoning visible and open to challenge. It also records which assumptions would change the decision, such as a large rise in subscription prices or a fall in firewall support quality.

Worked example

Weighted scores are B 4.2, C 3.6, A 3.1; sensitivity shows A approaching B only when cost dominates.

Synthetic case. Scores are synthetic.

Errors and limits

Choosing weights after seeing scores lets analysts steer results.

Exercises

EX100 — Option A weakness. Why did option A rank last? Rubric: 3 = limited logging failed detection needs;; 2 = logging;; 1 = cost;; 0 = none.
EX101 — Sensitivity purpose. What does the sensitivity analysis show managers? Rubric: 3 = choice depends on their priorities;; 2 = dependence on weights;; 1 = vague;; 0 = none.
EX102 — Revisit trigger. When might option C be reconsidered? Rubric: 3 = more reliable links or growth;; 2 = later;; 1 = never;; 0 = none.

Synthesis

Systematic comparison with visible weights and sensitivity supports a justified, revisitable decision.

Continue studying — chapter 34 of 40

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