Good day to everybody, as the title says, what are different ways of troubleshooting wireless network/equipment performance. Our company is using 100% ubiquity AP-AC's. One of my jobs is to optimize the performance so it is working great most of the time. I am also aware that the end-point device or client might be a culprit but I would like to minimize blaming the client, in better terms, I would like to justify better why/why not it is not performing as optimized. May I ask to be as nerdy(verbose) as possible, down to dirty details. There might be stuff I mentioned that may more or less be related to the wifi performance, but please answer those also in the same manner.
May I also ask what are the tools you guys use?
Scenario:
- School/Campus, one access point per classroom. Less than 40 people in a classroom. Ubiquity AP-AC access point says it can handle 200 concurrent clients. But according to people, the actual usage, high, medium bandwidth, is only 40 people, anything beyond that, will cause clients to lag(high ping).
- Open wifi, the only authorization is mac address auth under webmin(isc-dhcp-server)
Problems Encountered:
1) There are times some clients cannot receive DHCPOFFER even after registering the mac address, some times I have to turn-off their wifi and on. Single network, one subnet, /20. webmin tail grep syslog does not show any offer. Sometimes this takes couple of tries. (This problem does not occur to happen, Im waiting for this to happen so I can troubleshoot)
2) Client receives ip address, subnet, gateway, dns. But no internet (Does not happen often either)
3) According to some, they are being disconnected. But log says nothing about being kicked out(RSSI is off). Might be the end-point device.
What are the ways I know of:
1) Channel optimization
- There are minimal overlapping channels under 2.4ghz most of them are 30dB apart from each other. I think this is okay.
- Cannot disable 2.4ghz and use 5ghz as of yet as there might be clients that rely on that.
2) Limiting the power(radio) to only scope a certain room.
- The power of access points are low, based on the size of the classrooms here, it will only cover inside the classroom, when you go outside, power/signal will lower to 50-60dB
- Usage of minimum RSSI, this will kick clients out of the access point that will not meet the signal requirement. (Not using this atm because it might be considered as down time)
3) Ping tests from local to AP. Making sure there are no request-timed-out.
4) Wireshark + port mirroring, checking if there are segments that are cut/skipped(I think it means there are request timed-outs inbetween clients and whatever they are trying to access.
Tools I use:
1) Android wifi analyser
- Shows signal strength, ssid name, channel, quite fast in response to, like acrylic but mobile and portable
2) nmcli
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