802.11b Clients Stuck in Probing State

Unanswered Question
Dec 27th, 2009

Dear All

We are facing an issue where all our 802.11b Clients are stuck in Status "Probing". Please see the attachment (WLC_3_80211b_probing.JPG)

802.11b is already enabled, and we have changed the 11mbps data rate setting from "Mandatory" to "Supported" as per some older posts on this forum.

The controllers  Wireless >> 802.11b/g/n >> Network settings can be seen attached (before the 11 mbps change)

I have also attached "debug client <mac-addr>" output from one 802.11b client (001cbfbe2fc4.txt )

Please let us know the possible resolutions for this issue.

Controller: Cisco 4402  ( Software Version

WLC Country: SA

Device: Cisco Lightweight Access Point 1250 (LAP) is controlled through the 4402 Cisco Wireless LAN Controller (WLC)
The operating system version of the LAP: c1250-k9w8-mx.124-18a.JA



I have this problem too.
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avrquintero Sun, 12/27/2009 - 21:14

You can try to disable the 802.11b/g network first and re-enable to check. It doesn't matter if you use "Mandatory" or "Supported" on this data rate. According to Cisco, the AP will pick the next lower data rate allowed for that channel if the chosen data rate is not supported.

Farrukh Haroon Sun, 12/27/2009 - 22:14

Thanks, this problem was actually solved. It turned out to be an authentication-related issue.

However we have another problem:

The customer is complaining that  although he is using a relatively newer access point series (1250AG-N ), a lot of users on the network are complaining regarding the signal strength. If they replace the 1250 Series AP with an older one (1130) the signal strength isstronger .

Any pointers on how to tweak the signal strength without causing any other issues (like leakage,interference etc.)



George Stefanick Mon, 12/28/2009 - 14:15

Normally you would expect to hear your issue the other way around. First at both access points placed identically. What antennas are being used on the 1252 and last, what is the power setting of both ..?

Leo Laohoo Mon, 12/28/2009 - 15:38

I need more info.

How is the AP powered?  PoE or injector. 
If PoE, do you have both radios enabled?  What is the switch model?

Farrukh Haroon Tue, 12/29/2009 - 00:23

Thank you all for your responses.

The AP model is AIR-LAP1252AG-N-k9. The Antennas are built-in ones.

Attached is the output of the following commands

show controller Dot11Radio 0
show controller Dot11Radio 1



P.S I will post the power source and radio details shortly.

Farrukh Haroon Tue, 12/29/2009 - 03:57

To complement the show output in my previous post, I am now attaching the screenshots for the Radio configuration located at

Wireless >> Radios >> ....

Also the customer has confirmed that he is using power adaptor to power up the access point. And both radios are operational.

A combination of 2950,2960,3550 and 3560 Cisco switchesare being used.



George Stefanick Tue, 12/29/2009 - 11:52

When you say built in antennas, do you mean the ducky? Because the 1252 doesn't have built in antennas. Based on your screen shots the power is at max (1). So we can eliminate the RF power question for now.

Have you changed the data rates are they default? Are you sure these new APs are working and you can associate to them? Im wondering if you add put these online, but devices are connecting to further access points and not the 1252s.

Farrukh Haroon Tue, 12/29/2009 - 12:45

I meant the built-in radios, as mentioned in the data sheet:

• AIR-RM1252A-x-K9= 802.11a/n 5-GHz Radio Module; 3 RP-TNC
• AIR-RM1252G-x-K9= 802.11g/n 2.4-GHz Radio Module; 3 RP-TNC

Actually this is still a pilot phase, and only one AP is connected to the controller. I think the 1130 test was also done by connecting an Autonomous AP (not interfering with this LW-AP).


Farrukh Haroon Tue, 12/29/2009 - 22:40

I just mentioned in my previous post, the customer is using built-in radios. Please see the picture on top of this link:


Also please check this link:


These are the two radios *built-in* or bundled with the AP. They can even be detached.



Leo Laohoo Tue, 12/29/2009 - 23:16

Hey George,

I think he's using the gray rubber duckie antennaes.

I'm also thinking that we are barking against the wrong tree here.  If I get this right, 802.11b clients are stuck in "probing" state.  Correct me if I'm wrong here but when you configure your SSID you can specify which radios the SSID will be broadcasted on.  I'm suspecting he's misconfigured the SSID-related settings particularly the authentication stuffs.

avrquintero Tue, 12/29/2009 - 23:25

Yeah it seems we have some confusions here.

I think Farrukh already mentioned the this "Stuck in probing state issue" is already resolved and the new problem he got is the signal strength with the new AP installed.

It would be better if Farrukh can close this topic and post a new topic to avoid more confusions. 'Just a suggestion.

Farrukh Haroon Tue, 12/29/2009 - 23:36

Yes you are correct, but I had no idea they are called duckies

The 802.11b probing state issue was already solved (as mentioned at the beginning of this thread). So the clients can now connect!

Regards the config, just let me know which screen (GUI) you want and I can request a screenshot. The following is the relevant CLI config (let me know if you need anything else).

config 802.11b 11gsupport enable
config mobility group domain AB::C_GROUP

config wlan ccx aironetiesupport enable 1
config wlan broadcast-ssid enable 1
config wlan security wpa akm psk set-key hex encrypt 1 48 ... 1
config wlan security wpa akm psk enable 1
config wlan security wpa akm 802.1x disable 1
config wlan wmm allow 1
config wlan session-timeout 1 1800
config wlan interface 1 management
config wlan create 1 "ABC APs" ABC
config wlan exclusionlist 1 60
config wlan enable 1

config guest-lan exclusion-timeout 2 60
config guest-lan create 2 GUESTS
config guest-lan interface 2 management

config network rf-network-name AB::C_GROUP



zhenningx Wed, 12/30/2009 - 06:38

1252 does not have built in attenas.

• AIR-RM1252A-x-K9= 802.11a/n 5-GHz Radio Module; 3 RP-TNC
• AIR-RM1252G-x-K9= 802.11g/n 2.4-GHz Radio Module; 3 RP-TNC

These are modules for you to connect attenas.

You need to order attenas.


Farrukh Haroon Wed, 12/30/2009 - 09:15

Well obviously there must be something the pre-sales guy sold because the clients *can* connect, just the signal strength is slow.

Are you suggesting that the clients are connecting without antennas/radios in the AP?



zhenningx Wed, 12/30/2009 - 13:10

Yes, without external antennas, clients can connect to 1252 with very low signals. I don't know why. but the bottom line is, you need external antennas for 1252s. double check with your pre-sales guys.


George Stefanick Wed, 12/30/2009 - 14:01

The CISCO 1252 has 6 bulk heads whereby you can attach antennas. I am guessing you dont have antennas on your access point cause  you ref that they are built in and you are getting low signal ... These are NOT built in on the 1252...

Is there anything SCREWED into the 3 bulk heads on either end...

attached is a pix of my lab 1252 ... note the black sticks, these are antennas properly called dipole antennas, but most times ref as duckies.


Leo Laohoo Wed, 12/30/2009 - 15:05

Cisco released new details about new antennaes for the 1250.  You may want to check them out.

Farrukh Haroon Mon, 01/04/2010 - 04:51

Can you please provide any reference links for these new radios?

Also how can we check which radios are installed in an AP, any command?



Leo Laohoo Mon, 01/04/2010 - 12:56

Also how can we check which radios are installed in an AP, any command?

"sh version", "sh ip interface brief", "sh inventory"

Tony Davis Thu, 05/27/2010 - 06:20

Can you try to adjust your antenna gain from 0, to let's say, 3....


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