Chapter 39 — Capstone evaluation | Bachelor's Network and communications security

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Chapter 39 — Capstone evaluation

Lesson map

Lesson 39 published. Map, example, EX115.

flowchart TD
  N0["Learning outcomes"]
  N1["39.1 Results against requirements"]
  N2["39.2 Before and after"]
  N3["39.3 Limitations"]
  N4["39.4 Recommendations"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5
  N5 --> EX["Worked example"]
  EX --> Q["Exercise EX115"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["39.1 Results against requirements"]
  N2["39.2 Before and after"]
  N3["39.3 Limitations"]
  N4["39.4 Recommendations"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> Q["EX115"]

[Learning outcomes]
    |
    v
[39.1 Results against requirements]
    |
    v
[39.2 Before and after]
    |
    v
[39.3 Limitations]
    |
    v
[39.4 Recommendations]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX115]

Learning outcomes

You will (1) measure outcomes against requirements; (2) analyse before and after data; (3) state limitations.

39.1 Results against requirements

Priya evaluates each requirement. R1 is met: on-site tests and four weeks of logs show no allowed guest connections to internal groups. R2 is met: the policy denies all but the eight needed flows, verified by configuration review. R3 is met: management is reachable only from the administrator workstation. R4 is met for staff. R5 is met: the TLS audit now shows the lab results service on TLS 1.3, though the old intranet remains on TLS 1.1 and is scheduled for retirement. R6 is configured and partly evidenced.

39.2 Before and after

Before separation, flow records at the two clinics showed guest devices opening an average of 140 connections a week to internal groups, mostly printer and file-sharing discovery. After separation, allowed guest-to-internal connections are zero, while denied attempts average 95 a week and fall slowly as devices stop retrying. Guest alerts needing attention average two a week, with kappa of 0.70 supporting the labelling. The reachable group pairs fall from twelve to four needed pairs. Results are reported separately for each clinic as well as combined.

39.3 Limitations

The evaluation covers two clinics over four weeks after deployment, a short period that may not include unusual events. One clinic had only two weeks of before data. The guest measure before deployment came from a different source, checked for agreement on one day. Some evidence, such as recovery from firewall failure, comes from the lab only. Priya lists each limitation with its likely effect and states that results suggest, rather than prove, lasting improvement. These limits are repeated beside the results they affect.

39.4 Recommendations

Based on the evaluation, Priya recommends deploying the same design at the remaining two clinics using her documentation, retiring the old intranet, completing the ninety-day log retention check, adding certificate support for the remaining cart model when the supplier provides it, and reviewing the weekly routine after three months. Each recommendation has an owner and a target date agreed with the IT lead, so the project's value continues after her capstone ends. The recommendations are ordered by risk reduction, so the clinics can act on the most valuable ones first if time or money is short.

Worked example

Reachable group pairs fall from twelve to four; allowed guest-to-internal connections fall from about 140 a week to zero.

Synthetic case. Data are synthetic.

Errors and limits

Claiming permanent improvement from four weeks of data overstates the evidence.

Exercises

EX115 — Reachability outcome. How did reachable group pairs change? Rubric: 3 = twelve to four needed pairs;; 2 = reduced;; 1 = vague;; 0 = none.
EX116 — Continuing denies. Why do denied guest attempts continue after separation? Rubric: 3 = devices keep retrying discovery; fall slowly;; 2 = retries;; 1 = attack;; 0 = none.
EX117 — Remaining TLS gap. Which TLS gap remains and how is it handled? Rubric: 3 = old intranet on TLS 1.1, scheduled for retirement;; 2 = old intranet;; 1 = vague;; 0 = none.

Synthesis

Evaluation against requirements, with honest limits, shows what the capstone achieved and what remains.

Continue studying — chapter 39 of 40

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