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AIR-AP1041N-A-K9 - %DOT11-6-DISASSOC Reason: Sending station has left the BSS


Mar 28 2012 13:05:32 UTC: %DOT11-6-ASSOC: Interface Dot11Radio0, Station   b817.c212.2121 Associated KEY_MGMT[WPAv2 PSK]

Mar 28 2012 13:05:47 UTC: %DOT11-6-DISASSOC: Interface Dot11Radio0, Deauthenticating Station b817.c212.0000 Reason: Sending station has left the BSS

We have about a dozen of these standalone AP's at different offices in different states. Any of my windows XP or 7 client computers who connect to any of these access points will lose their Wifi connection for about 3-8 seconds at a time (just long enough to drop me from all my interactive applications). There was even a macbook who drops just the same.  I was working on wireless myself yesterday and it happened 4 times in 8 hours.   I was sitting approximately 15 feet from the AP with "Excellent Signal", no obstructions, clear LOS... a wide open area.  As for interference, there are two other SSID's with 1 bar each from other suites.  It's not really even close. Also with regard to interference, I'm sorry to say but the 802.11g Netgear WAP's which we replaced with the Cisco never dropped anyone. I do not believe this is interference related.

It's been going on for weeks (since we deployed them), and I've tried different encryption types. I've read many many forums with reports of Aironet AP's frequently disconnecting with this error.  None of the ones I've read have any clear conclusion or resolution. They all end with people suggesting it's signal or interference and nobody reporting back.  It seems that some of these WAP's seem incapable of holding a connection for more than a few hours, even under good conditions. All of mine have this problem.

I've been using Wifi for many years in many environments, but never used the Cisco AP's.  I feel strongly that the AP's are causing the disconnects, and that it's not the environment or signal or anything like that.  My hope is that there are some well-known configuration modifications for these things that can make them actually be stable.  I'm happy to run any show or debug commands to determine if something else is leading up to this error.  I am CCNP RS, but this is my first experience with the wireless products.



Community Member

AIR-AP1041N-A-K9 - %DOT11-6-DISASSOC Reason: Sending station has

So, 32 views and no response in 2 days.

I don't know how to bump this, or if it's even possible. I would even like to pay for a TAC case if it's possible, since I don't think I can get smartnet on these things.

Pending some response with a solution,  one can only conclude that things have some sort of defective code, or a hardware defect. There are so many other cases where people report this issue and it doesn't get resolved, I can't imagine what the resolution could be.

Please help Cisco.




AIR-AP1041N-A-K9 - %DOT11-6-DISASSOC Reason: Sending station has

Hi Jerry,

Please post the show tech from one of the APs where this is happening.

Also, do you have the ability to take an over-the-air wireless sniff?  Unfortunately, this issue will most likely require a wireless sniff to actually see what's happening in the air.

Hall of Fame Super Blue

AIR-AP1041N-A-K9 - %DOT11-6-DISASSOC Reason: Sending station has

So, 32 views and no response in 2 days.

A significant number of us who post solutions do NOT work for Cisco.  We work during our spare time.  Some of us work in environments where surfing the internet during office hours if frowned upon (even if you are trying to get solutions).

As for the Cisco guys/gals, they too post solutions during their spare times.

Now back to your problem.  I see a number of questions.  Firstly you are using a 1041 WAP.  This means you only have one radio and this will have to be the 802.11b/g radio.  Add the issue of the number of usable channels you can use (three compared to twelve for the 802.11a/n radio).  So you will need to know if your neighbors have other WAPs in place and broadcasting on the same channel as you.  You will also need to know if all of your WAPs are broadcasting in similar channels or other forms of channel interference.

I was sitting approximately 15 feet from the AP with "Excellent Signal", no obstructions, clear LOS... a wide open area.

That's not a good "indication".   On the nearest WAP, enter the following command and post it:  sh dot11 assoc detail".

And you need to tell us what is the signal strength your client sees the WAP.

Community Member

AIR-AP1041N-A-K9 - %DOT11-6-DISASSOC Reason: Sending station has

Thanks for the feedback guys, I really appreciate your time.  The information requested is below... please continue to request outputs of show commands and we'll try to diagnose the problem methodically.

Also, at this time I will clarify my suspicion: The first error indicates that the Client has left and thus de-authenticates. Since we know that the client is not specifically requesting to disconnect, we can infer that the WAP is choosing to disconnect the client because it hasn't "heard from" the client for the timeout period (20 seconds I believe).  I believe the clients are all in fact continuing to send the packets, and the WAP is simply missing them due to a common hardware or software issue, or a set of configuration parameters which makes it unstable and sub-optimal (resulting in it missing packets for up to 20 seconds).

Now, I can already see that this investigation is heading toward me being asked to "Prove" that the clients are sending the packets and "Prove" that the WAP is not receiving them using two simultaneous packet captures (one from wireless adapter and one from the switchport connected to the WAP).  I'll do this to prove my theory, but I'm REALLY hoping that someone admits to a previously known bug or limitation, because the behavior and quality of these WAP's are the one thing I am unfamiliar with.  Everything else I feel confident about.  Here is the output that was requested:

Leo: Show Dot11 Assoc mac

David:  Show Tech


As I explained before, this environment is somewhere between "fair" and "good" for operating a wireless network.  I've run many consumer-grade wireless products in very crowded airspaces where speeds weren't great and retransmits were high, but disconnects were still very rare. In this specific environment, with our old cheap netgear WAG102's, we had reliable signal and connectivity. Up to 10 people could sit in the designated area and work throughout the day, and never was reported a disconnect. Speeds weren't amazing when it was busy, and the radius of coverage wasn't great, but everybody had full bars and it was reliable.

Now, we've upgraded to Cisco because we use network monitoring and configuration management applications which work great with Cisco IOS based devices, and all the rest of our network is Cisco. Also, we wanted devices which are under a current warranty. These WAP's fit very nicely, even if they're single G radio just like the Netgears... they should at least be a little better I thought. Right now, with these WAP's, disconnects occur multiple times for every person every single day.

Keep in mind, we can't do much to improve the environment, distance, or positioning, which are the primary factor. At this point, all we can really change is the configuration.  If we can't find a way to tweak configurations to make this reliable, the last thing I can do is replace the WAP's... and that will make me very sad.



Community Member

AIR-AP1041N-A-K9 - %DOT11-6-DISASSOC Reason: Sending station has

Well, it's been a few days.  Has anyone had a chance to look at the show commands and identify any potential causes for my symptoms?


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