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Frequent client disconnection on specific AP's

Unanswered Question
Jul 18th, 2012
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Hi


There are frequent disconnections only for a few clients connecting on specific floors.


Seems to be something to do with the access point or the path ..


The signal strength drops intermittently


what would be the steps to isolate the issue                  

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Dave Anthony David Wed, 07/18/2012 - 06:31
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Did you check the interference on that specific floor?

You can use inSSIDer software to check the channels, signal strength.

TGF_Cisco Wed, 07/18/2012 - 06:34
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Discovery phase statistics
- Discovery requests received.............................. 10
- Successful discovery responses sent...................... 10
- Unsuccessful discovery request processing................ 0
- Reason for last unsuccessful discovery attempt........... Not applicable
- Time at last successful discovery attempt................ Mar 29 17:38:09.190
- Time at last unsuccessful discovery attempt.............. Not applicable

Join phase statistics
- Join requests received................................... 5
- Successful join responses sent........................... 5
- Unsuccessful join request processing..................... 0
- Reason for last unsuccessful join attempt................ Not applicable
- Time at last successful join attempt..................... Mar 29 17:38:20.030
- Time at last unsuccessful join attempt................... Not applicable

Configuration phase statistics
- Configuration requests received.......................... 15
- Successful configuration responses sent.................. 5
- Unsuccessful configuration request processing............ 0
- Reason for last unsuccessful configuration attempt....... Not applicable
- Time at last successful configuration attempt............ Mar 29 17:38:20.221

--More-- or (q)uit
- Time at last unsuccessful configuration attempt.......... Not applicable

Last AP message decryption failure details
- Reason for last message decryption failure............... Not applicable

Last AP disconnect details
- Reason for last AP connection failure.................... Data transfer message received from an unsupported AP

Last join error summary
- Type of error that occurred last......................... AP got or has been disconnected
- Reason for error that occurred last...................... Data transfer message received from an unsupported AP
- Time at which the last join error occurred............... Mar 29 17:12:04.596
                                                                                Ethernet Mac : c8:4c:75:61:11:da  Ip Address : 172.19.6.21



Could this be causing some issue?? It had been working fine but all of a sudden there are disconnections.. Users are not able to connect for more than 5 mins.. 


Are there any debug commands that would be able to isolate the issue?

TGF_Cisco Wed, 07/18/2012 - 06:41
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Hello


I am using  AIR-LAP1142N-E-K9 (12.4(23c)JA) and  AIR-CT5508-K9 (7.0.98.0) on all the access points.

TGF_Cisco Wed, 07/18/2012 - 07:09
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There seems to be freqent disassociations


07/18/2012 15:26:17

18 min 25 sec

host/L05558

2c-ap5-beg

Ctr1

Xx> Main > 2C

YY-users

802.11g

2.3

07/18/2012 15:21:16

5 min 0 sec

host/L05558

2c-ap6-mid

Ctr1

Xx> Main > 2C

YY-users

802.11g

1.3

New association detected

07/18/2012 15:11:15

10 min 0 sec

host/L05558.

2c-ap5-beg

Ctr1

Xx> Main > 2C

YY-users

802.11g

8.4

New association detected

07/18/2012 15:06:15

5 min 0 sec

host/L05558.

2a-ap3-beg

Ctr2

Xx> Main > 2A

YY-users

802.11n_2.4GHz

<0.1

No longer seen from controller

07/18/2012 14:56:14

10 min 0 sec

host/L05558.

3a-ap8-beg

Ctr2

Xx> Main > 3A

YY-users

802.11n_2.4GHz

<0.1

New association detected

07/18/2012 14:51:14

5 min 0 sec

host/L05558.

2a-ap3-beg

Ctr2

Xx> Main > 2A

YY-users

802.11n_2.4GHz

<0.1

New association detected

07/18/2012 13:50:33

55 min 40 sec

host/L05558.

3a-ap8-beg

Ctr2

Xx> Main > 3A

YY-users

802.11n_2.4GHz

0.2

Disassociation detected

07/18/2012 13:45:32

5 min 0 sec

host/L05558.

2a-ap3-beg

Ctr2

Xx> Main > 2A

YY-users

802.11n_2.4GHz

<0.1

New association detected

07/18/2012 13:25:30

20 min 1 sec

host/L05558.

3a-ap8-beg

Ctr2

Xx> Main > 3A

YY-users

802.11n_2.4GHz

0.2

New association detected

07/18/2012 13:20:30

5 min 0 sec

host/L05558.

2a-ap4-end

Ctr2

Xx> Main > 2A

YY-users

802.11n_2.4GHz

<0.1

New association detected

Leo Laohoo Wed, 07/18/2012 - 16:08
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What is the signal strength the clients are seeing the wireless?

What radio?

TGF_Cisco Mon, 08/13/2012 - 08:34
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Disconnections are happening on 802.11n 2.4GHZ primarily but not restricted to that frequency. Please check the same log given previously.


Signal strength visibly drops when I try to connect on Wifi in that floor.

What else could I run to diagnose the issue?

Leo Laohoo Mon, 08/13/2012 - 23:27
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Disconnections are happening on 802.11n 2.4GHZ primarily but not restricted to that frequency.

Sounds like a combination of channel interferrence (as 2.4 Ghz has only 3 non-overlapping channel) and low wireless signal.


Can you describe the physical location of the clients in relation to the WAP?


Are the clients in one floor and the WAP in another floor?

Are the clients in one side of the building and the WAP in another side of the building?

TGF_Cisco Tue, 08/14/2012 - 06:28
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Let me give a more precise scenario


The problem I am assuming only exists in the 8th floor . No other complaints.


2 WAP-  8A- Beg, 8A -Mid


1. 8A- Beg - connecting to controller 1 - On controller 1 "n" is enabled on 5 GHZ and not enabled on 2.4 Ghz
2.  8A -Mid- Connecting to controller 2 - on controller 2  "n" is enabled on 2.4 Ghz  and not enabled on 5 Ghz


This is how we got this implemented long back and had no issues so far until a month ago.

Will this cause an issue? Which is the preferred way of setting n parameters? I guess it would be best to enable n on both the frequencies? I would like to go more in depth about configuring n parameters and fine tuning them so that we dont face such issues again in other floors and hope to resolve the current issue.


thanks

Reginald Pugh Wed, 08/15/2012 - 06:58
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How many users?.  Are they startng to bring on more devices/count ? See if there are other SSIDs stronger in the area. If you have 802.11n enabled on 2.4GHz this can be a problem- less channels to work with .-Interference?

fbarboza Wed, 08/15/2012 - 09:18
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Hi ,


Please upload the show msglog of the WLC, the show run-config and let us know the WLAN with the issue and the access point name or MAC address where the issue is occuring.

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