Wireless Troubleshooting

What this chapter covers

Wireless Troubleshooting is about finding out why a wireless client is slow, unstable or cannot connect.

It uses the registration table as its main instrument. The table gives signal, rates, quality and counters for every connected peer, and each of them points to a different kind of problem.

The chapter follows one syllabus topic that lists six items. It has three pages, and each page groups items that are used together.

How the topics fit together

A good diagnosis starts with the signal and ends with the settings that cause the symptom.

The pages follow that order:

• Registration table and signal shows how to read the table and compare the two directions.
• Ack timeout, distance and CCQ shows how timing and link quality affect throughput on long links.
• Frames, hw frames and data rates shows how retries and rate lists describe the state of the link.

Each page adds one more clue. Used together they let you tell a weak signal from interference, and a timing fault from a rate fault.

How to use these pages

Each topic page has the same shape, so you can skim for what you need.

• What it is: the idea in plain words.
• How it works: the mechanism, with diagrams and example commands.
• What to remember for the exam: the facts to memorise.
• Common mistakes: the classic traps.
• Check yourself: three questions to test your understanding.

The syllabus marks this topic as a lab, so practise on a real link if you can. Print the registration table, write down each value in plain words, and change one setting at a time to see which value moves.

The tools from the previous chapter fit in here. Use the scan and the frequency monitor to check for interference once the table points that way.