One desk cannot connect
Desk 14 has no connection. Desk 15, next door, works. A new installer swaps the switch, the cable and the computer all at once. The desk works again, but nobody knows which change fixed it.
A good fault-finder works in a fixed order, changes one thing at a time and writes it down.
Key words
| Word | What it means |
|---|---|
| Fault | something that stops a system doing its job |
| Routine monitoring | checking a system on a schedule, before anyone complains |
| Diagnosis | working out the cause of a fault from the facts |
| Baseline | the record of how a system behaved when it was working well |
| Eliminate | rule a cause out because the facts do not fit it |
| Shortlist | the few causes that are still possible |
| Resolution | the fix, and the steps that stop the fault coming back |
| Network | devices joined so they can share data |
| Network plan | the record of what is installed and every change made to it |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can follow the four stages of troubleshooting and apply them to a fault.
Starter: testing
Have a go
Starter: testing
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Stage 1: identify the problem
A problem is found in one of two ways. A fault occurs and a user reports it. Or routine monitoring spots it first.
Write down what is wrong, where, since when, and who is affected. Be exact. "No network at desk 14 since 9 am" is better than "it is broken".
Stage 2: diagnose
First gather information. Ask what the user did and what changed. Use the reporting tools: logs, alerts and the lights on the ports.
Then analyse. Compare with the baseline. Compare with a similar system that works, such as the next desk. Finally consider the causes: eliminate what the facts rule out, and list what is left.
Stage 3: test what is left
Test the shortlist one cause at a time. Change one thing, then check. If a cause is wrong, rule it out and move on. Keep going until one cause explains the fault.
Changing many things at once hides the answer.
Check: the first three stages
Have a go
Check: the first three stages
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.