02-09-2011 10:47 AM - edited 07-03-2021 07:48 PM
Hi Folks
Please have a look to attachment and advise me what is the reason of the problem and how to troubleshoot this?
02-09-2011 01:20 PM
Ok getting back to the client in probe state ..
1 Check your Radius server and see if that client is failling authentiction
2. Capture the entire debug on the client. When you see a client in the PROBE state it normally means its not getting on at all... I would double check the clients config . Also under WLAN are you using 802.1X+CCKM, just CCKM ... what?
As far as the clients disconnecting, are they in good coverage? What type of client, phone, laptop ?
02-09-2011 11:40 PM
Hi and thanks for ur reply!
The User has Laptop and the signal srenght is Excelent,regarding security am using just 802.1X,
is the command to capture the client details"debug client
02-10-2011 05:50 AM
Understood, but need more deatils:
What rev are your controllers on
What 802.1X (PEAP?)
What encryption WPA/WPA2?
Do all the laptops disconnect at once? Do they disconnect at a certain time ?
Do the laptops disconnect or are they having application issues?
Also, can you post the entire DEBUG for the problem client ?
02-10-2011 09:08 AM
Hi Gorge
-full code 6.0.199.5
-802.1X -EAP
-encryption WPA/WPA2
- they disconnect at a certain time
-laptops disconnect than having application issues
Please see the below from the WCS 4.0 when client got disconnected
interface '802.11b/g'. Channel changed to '1' from '9' due to 'Interference'. Interference Energy before update is '-75' and after update is '-72'. Noise before update is '-91' and after update is '-92'. Interference before update is '-85' and after update is '-111'.
How do i check this interference and tacke it , it didnt appears on the controller
02-10-2011 09:35 AM
A few items ... Lets get back to basics ...
Your WCS should be on the same or higher version when comapired to your WLC. If you are running WCS 4 and have your controller on 6, your data in WCS may not be very accurate
On your client on your WLAN-->Advance-->Check boc session time out ... See is this is enabled, if it is disbale it for me
If you are using 2.4GHz 802.11b/g your access points should be on channels 1,6,11. I would not use any other channels other than 1,6,11
If you suspect interference, do you have a spectrum analyzer ? If you dont, on your wireless laptop you will see a noise floor figure, what does it say. It will be like -90 ..
02-10-2011 10:13 AM
hi
on your wireless laptop you will see a noise floor figure, what does it say. It will be like -90 ..how can i verify that?
also from where the noise comes? does any thing wrong on the controller
can y help me in special doc that let me maintain well my wireless network
02-10-2011 12:12 PM
On your laptop. What wireless supplicant are you using? For example, if you use Intels supplicant you can hit details on your WLAN and it will show you the noise floor and signal strength. However, having a spectrum analyzer is your better bet but they are a little costly. But I would also question WCS, dont always take WCS as the "word".
If your clients are all getting disconnected at the same time, that is a tell tail sign of something is going on. But here again, you cant see RF unless you have the proper tools.
If you visit my blog and look on the right hand side of the home page you can see what interference looks like so if you have a spectrum anallzyer you will see something similar to these ..
www.my80211.com
For the client that isnt getting on. We can work through that but you need to capture the complete debug from the cli. Thats the only wany we can walk through that piece at the moment.
02-10-2011 03:08 PM
hi Freind
nice blog,thanks
r y thinking my interference due to the following:
1)Bluetooth
2)Cordless Phone
3)jammer
4)Microwave oven
T he only thing i have from the above is the cordless phone,how do i know its indeed from it? is there any software discover that for me?i heaed about this "Cisco-Aironet-Site-Survey-Utility-v1301" is this 1 good for my situation? pls advise something else
can u please tell me the story of wireless flow from ur expertise point of view,e.g the procees from the begining how client contact the LAP then WLC then ACS then Active Directory,how the ms DHCP send ip for the client
thanks
02-10-2011 06:36 PM
I cant say for sure if you even have interference. I wouldn't use just WCS to tell you that you have interference, because its not always accurate.
I think you need to see and confirm a pattern if any in regards to your wireless issues. Ask your users about the problem and see if you can reproduce it.... Try to see the issue for yourself.... Asking the right questions and troubleshooting wireless takes a lot of experience. Sometimes years of learning and hands on to get it down to a science.
Wow, the flow of wireless could be a REALLY long email. Lets cover the basics. But better yet I will direct you to some reading:
To learn wireless in general I would direct you to CWNP.com. Although they have a certification program, if you arent interested in certifications I would read the books to get a better udnerstanding of 802.11. The books and cert programs are the CWNA, CWSP and 2 new books which will be out later this month CWDP and CWAP. CWNP sets the fundementals for wireless. In fact, I know some of the authors personally and was personally mentioned in the CWSP and CWDP books.
To better undertand Cisco Wireless. I would direct you to reading the design guides, example and config guides. As for book reading I would read the CCNA wireless by Brandon Carroll and CCNA Wireless Study guide by Todd Lammle. I was a technical editor on Todd's book.
I hope this helps ...
02-10-2011 06:08 PM
So what is noise ...
here is a good example ... suppose you and i are talking on a phone. During our conversation, the phone gets statically or perhaps there is someone yelling in the back ground. We would interpret this as noise, right.
Well wireless client work very similar to this. Wireless lives on the 2.4GHz if you run 802.11b/g or 5GHz if you are on 802.11a/n. These frequency's are used for more than just WiFi wireless. You will find cordless phones, microwave ovens, baby monitors, motion cameras, and the list just goes on and on.
Lets pick on a Microwave. Most microwaves cause interference on the backend of the 2.4GHz band. So asssume you have a AP on channel 11. The microwave kicks on and your wireless client is trying to send data. Depending on the amount of interference some or none of your packets will make it from or to the AP.
To see interference you need to have special tools. For exmaple ...
Layer 1 -- the spectrum can only be seen with a spectrum analyzer. Like the CIsco Spectrum Card, AirMagnet XT, or the WiSpy. Here are a few links to educate yourself:
http://www.cisco.com/en/US/products/ps9393/index.html
http://www.metageek.net/products/wi-spy/
http://www.airmagnet.com/products/spectrum_xt/
Layer 2 -- Is the 802.11 frame work. When you have interefernce you can see this by the high nosie floor, excessive channel utilzation and high retrys. Here are a few tools that you use ...
http://www.airmagnet.com/products/wifi_analyzer/
http://www.wildpackets.com/products/network_analysis_and_monitoring/omnipeek_network_analyzer
I will warn you these tools arent cheap. They are pretty expensive, but to work wireless properly you almost need the right tools.
I hope this helps
02-11-2011 02:57 AM
Hi
1) If you dont wan go for deidicated tool you can use netstumble to monitor your enivorment.
2) as client disconnection problem poor network coverage can be reason or some of your access points are droping. check your WLC log you will come to knwo if any Access point drops.
3) for client probing: is every client out there facing this problem or perticular one. long time in probing state means there is some authontication error even some time NIC card is itself creat problem.do the following to troubleshoot.
Put your security to None
disable client MAC filetering
Enable SSID Broadcast
Disable all security parameters(if applied)
now try to connect your cili ent now and see if it connect now see if associating if yes then higher your security setting and check. if this is the case only with perticular client then may be your NIC card is compatible.
02-11-2011 01:56 PM
Thanks to all of you,Thanks Goerge
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