Wireless client is not stable when connect AP 3802

[giangle]

Hi all

Diagram

WLC 5520-------------Switch------------AP 3802i

WLC 5520 and AP 3802i with OS: 8.5.140.0

And my issue:

- Client access WLAN by tablet and laptop. Some of them are not stable when access Internet and some client disconnect wireless with APs. I also check radios with Wifi Analyzer Pro. Client is about -60 dbm and distance between about 10m.

In Controller, I show this AP with RSSI and SNR and result from Wifi Analyzer Pro as attachment file.

I don't know when client disconnect with AP, how can I check log in Controller.

Please help me to investigate this issue. Many thanks!

[Scott Fella]

When you troubleshot client issues or complaints, the first thing to do is try to replicate it yourself.  Then try to isolate the issues with what devices are working fine and what are not.  That can help you investigate the issues like drivers or maybe a bad wireless profile on the device.  I run the same setup and have no issues at all, that being said, you should create a test SSID that is open with basic configuration and test.  Then slowly move to PSK and then 802.1x and see where things start to fail.  There is also debug commands and guides to troubleshoot client issues, but that should be done after or while you are isolating device types.

Search for "cisco wlc client troubleshooting"

[Leo Laohoo]

1. What, EXACTLY, is the problem? 
2. Is this happening to one person('s device) or a lot of users?
3. What are the different APs used?
4. Isolate and identify what wireless clients are affected (based on OS or SSID or location).
5. What, EXACTLY, is the error message being displayed? 
6. What radio are the issue(s) more prominent?
7. Have you VERIFIED and replicated the issue?

[giangle]

Hi @Leo Laohoo 

For this issue, are there any tools to measure the wave between 2 devices AP. I want to know if wave is overlapping. Thanks

[JPavonM]

The only way to "view" the waves is using an oscyloscope but you need to understand what you are seeing.

There are some WLAN tools you can try to use in order to check the spectrum such as Ekahau Sidekick, to check for overlapped networks that maybe affecting performance due to co-channel interference or any other RF issue there could be.

As @Scott Fella and @Leo Laohoo told you, you need to be able to repplicate the issue with the same device (wNIC, OS, drivers and patches) under the same area, then try to replicate the issue in another area/AP, and then try to replicate it with another different device from the same kind (laptop or smartphone) but with different wNIC and/or driver version.

If this is affecting always the same devices, then you have some clues about where the problem could be.

Most of the times this kind of issues hitting some devices are solved standardising the deployment in terms of wNIC, OS and drivers.

Then if after testing with up-to-date end-user devices is not good, try to start with an Open SSID, moving to PSK and then to 802.1X if this is your setup. It is also highly recommended to disable all 802.11 ammendments such as FT, dot11r/k/v/w and enabled then one-by-one after testing the before setups.

But before all, I'd recommend you to update the 5520 WLC to latest TAC recommended release in your current train 8.5 from 8.5.140 to 8.5.171.0 (https://www.cisco.com/c/en/us/support/docs/wireless/wireless-lan-controller-software/200046-tac-recommended-aireos.html#anc9)

At the end, if everytihing fails, think into moving to Cisco TAC recommended release 8.10.162 for deployments without dot11ax APs (https://www.cisco.com/c/en/us/support/docs/wireless/wireless-lan-controller-software/200046-tac-recommended-aireos.html#anc4).

HTH
-Jesus
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[Leo Laohoo]

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@giangle wrote:

For this issue, are there any tools to measure the wave between 2 devices AP. I want to know if wave is overlapping. Thanks

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I do not believe this answers any of my questions.  

[Scott Fella]

Please try to follow and do what we asked from you.  This really helps decide which way to go next.  With such a broad question, there is no way to help you at all.  It's like saying, "My car makes a noise in the morning, but I don't always hear it and nobody else hears it."

There are always basic items that needs to be provided in order to generally answer any question on the forum.  You don't want to answer one or two items at a time, because then the thread gets long and folks get lost.  No one wants to read a very long thread.