Chapter 30 — Laboratory II
Lesson map
Lesson 30 published. Map, example, EX088.
flowchart TD
N0["Learning outcomes"]
N1["30.1 Full rehearsal"]
N2["30.2 Failure and recovery tests"]
N3["30.3 Rollback plan"]
N4["30.4 The lab report"]
N5["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> N5
N5 --> EX["Worked example"]
EX --> Q["Exercise EX088"]
Logical drawing
flowchart LR
N0["Learning outcomes"]
N1["30.1 Full rehearsal"]
N2["30.2 Failure and recovery tests"]
N3["30.3 Rollback plan"]
N4["30.4 The lab report"]
N5["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> Q["EX088"]
[Learning outcomes]
|
v
[30.1 Full rehearsal]
|
v
[30.2 Failure and recovery tests]
|
v
[30.3 Rollback plan]
|
v
[30.4 The lab report]
|
v
[Synthesis]
|
v
[Worked example] --> [Exercise EX088]
Learning outcomes
You will (1) rehearse a complete deployment in the lab; (2) test failure and recovery; (3) produce a lab report.
30.1 Full rehearsal
Before proposing deployment at a clinic, Priya rehearses the whole change in the lab: creating the new wireless networks, moving test devices into their groups, applying the firewall rules, enabling logging and running every test. She times each step. The rehearsal takes three hours, which tells the clinics how long a real change window must be. It also exposes ordering problems, such as needing the management network working before access points can receive their new settings. She updates the deployment checklist to put steps in the right order.
30.2 Failure and recovery tests
Priya simulates failures. She restores the firewall from its backup configuration and checks all tests pass afterwards; she expires a test certificate and confirms the monitoring script reports it; she stops logging from one device and confirms the completeness check notices within an hour. Each test has an expected outcome written beforehand. Testing recovery matters as much as testing protection, because a design that cannot be restored quickly after a failure will tempt staff to bypass it. Results are added to the lab report with timings.
30.3 Rollback plan
Every deployment needs a way back. Priya's rollback plan saves the existing configurations of the access points and firewall before changes, sets a decision point two hours into the window, and reverts if critical tests have not passed by then. She practises the rollback in the lab and it takes twenty minutes. Having a rehearsed rollback lets the team stop calmly rather than troubleshooting under pressure while clinic staff wait for systems to return. The saved configurations are tested to load correctly before each window, so rollback is known to work.
30.4 The lab report
Priya writes a lab report covering the setup, tests, results, failures found, fixes and limits. It includes a table linking each requirement to its tests and results. The report is short, around six pages, and written for the clinic IT lead as well as her tutor. It becomes the basis for the deployment proposal she will present later, and it gives the clinics evidence that the design was tested carefully before anyone touched their network. An appendix lists the exact rule set version tested, so the report can be matched to configurations later.
Worked example
The rehearsal takes three hours; rollback takes twenty minutes; all twenty-six tests pass after two fixes.
Synthetic case. Lab results are synthetic.
Errors and limits
A rollback plan that was never practised often fails when needed.
Exercises
- EX088 — Rehearsal timing value. What did timing the rehearsal tell the clinics? Rubric: 3 = required change window length;; 2 = window;; 1 = vague;; 0 = none.
- EX089 — Rollback decision point. What is the purpose of a decision point in the window? Rubric: 3 = revert calmly if tests not passed;; 2 = stop;; 1 = vague;; 0 = none.
- EX090 — Report audience. Who is the lab report written for? Rubric: 3 = IT lead and tutor;; 2 = IT lead;; 1 = tutor only;; 0 = none.
Synthesis
A full rehearsal with failure, recovery and rollback tests prepares a safe real deployment.
Continue studying — chapter 30 of 40
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