9800 wlc strange issue with 3800 AP's

[Anjana A]

Hello All,

This is a very peculiar behaviour observed in 9800 wlc  and associasted access points are 3800AP.

have done proper survey through ekhau tool and placed the access point,at times in a floor all the users getting connected to single AP ,despite of all the available access points.

The other access points will have minimal number of users but one ap getting crowded.

Verified the power and signal strength the all the AP's found to be automatic by the wlc.

Pls suggest what to check on this.

This happend with only one floor in our infra ,all the other ap's in that infra other floors not facing the issue.

Regards,

Anjana

[marce1000]

  - Clients make roaming decisions autonomous , you verified AP signal quality for 'honored wireless resources' but perhaps interferers at that location lead to that siuation ; the RF environment should be examined ,

 M.

[Anjana A]

@marce1000  thanks for the input.

To be more clear need to check the thirdparty intrefrence and the rogue AP on that point of time.

[jagan.chowdam]

I recommend following these steps -

1. Check the power and signal strength settings on all access points. It's good to know that you have already verified that the settings are set to "automatic" by the WLC. However, double-checking this is essential, as incorrect power settings can lead to coverage and connectivity issues.

2. Download the "show tech wireless" output from your 9800 controller. This command will provide a comprehensive snapshot of the wireless environment and configuration.

3. Use Cisco Wireless Config Analyzer Express to analyze the "show tech wireless" output. This tool will help you identify any potential configuration issues and assess the overall RF health.

You can find the Cisco Wireless Config Analyzer Express tool details at the following link: https://developer.cisco.com/docs/wireless-troubleshooting-tools/#!wireless-config-analyzer-express/quick-feature-list

By performing these steps, you can narrow down the possible causes of the crowding on one AP and identify any configuration or RF-related issues.

-CJ

[docjb0221]

You can force clients to move sooner by adjusting the RF profile and to disable the lower data rates.

[Anjana A]

yeah i have done it manually by increasing signal strength of nearby Ap and reducing power of more crowd ap..

here trying to understanding the root cause and reason for this kind of behaviour.

this is second time landed in same kind of issue

[Leo Laohoo]

Are these Windows-based wireless clients?

[Anjana A]

yeah.. almost everyone are windows based clinets @leo

[Leo Laohoo]

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@Anjana A wrote:
almost everyone are windows based clinets @leo

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Are the wireless NIC drivers up-to-date?

[Anjana A]

1. yeah.. almost all users using dell drivers and its up to date.

[Leo Laohoo]

Pick a wireless client connected to that AP and share the output to the following command:

sh wireless client mac <MAC ADDRESS> detail | section Nearby AP Statistics

If the response is blank, keep looking for a wireless client where the response is not a blank.

And from that wireless client, post the "first page" of the Windows command:  

netsh wlan show drivers

[rileybrok]

Thank you for amazing Info. I will add it as a reference at my blog post.

[JPavonM]

It has some sense what you told about reducing power on the loaded AP and increasing power on nearby APs seem to fix the lad balancing between them. This could be due to a sticky behaviour from clients if that heavily loaded AP is the first one on the path to the office space. 

You don't mention if this SSID is broadcasted in all bands or just only 5-GHz, but using 2.4-GHz band which has a wider effective connectivity range increase that behaviour.

My recommendation, create RF profiles with 3dB difference only on Max/Min TX power level thresholds (14/11, 11/8, 8/5, 5/2), and perform a proper survey using that RF profile with every combination. Ensure you have proper Primary and Secondary signals at all areas (ideally -65dBm/-68dBm). While you perform this surveys, you can also test the supported rates in order to see when the survey device roams conducting and Active survey: my recommendation use 12- or 24-Mbps as basic rate depending on the AP density, and only support those from 12- to 54-Mbps.

These tests will tell you the proer configuration for TX Power a rates. If the device sticks to any AP during the survey you will be able to check which one and the coverage range for that one, so giving you a hint about how to proceed.