Handheld Scanners not finding Wireless Network

[Ryan Curry]

Hi all, I've run into an issue that I believe is a device issue but wanted to run it by this group of experts first.

Three weeks ago I moved all the APs at one of our sites from WISMs (running 5.2.193) over to a pair of 5508s (running 7.0.220) and everything appeared to be fine through testing and implementation.  We've got about 400 devices on this network and almost everything is working without issue, except for about 10 Honeywell Dolphin hand-held scanners that our distribution department uses.  On occasion when the users go to use them, even when sitting 15 feet from an AP, the device will kick out an error that the "wireless network was not found - please move closer to an access point or return to cradle".

As much as I would love to say it's a device issue, they said the problem started the same day I moved the APs to the new controllers (they gave me the date they started experiencing the issue, I was able to link that back to the date I made the move).  They worked without issue on the old controllers / code and, for the most part, both old and new controllers are configured similarly (except for enabling a few new feature that the new code supports like client-link and band-select).  These are b/g clients and I did diable all .11b data rates when moving to the new controller.  Also, this happens in multiple locations, not just in the receiving / distribution area.

Lastly, I'm at my wit's end on this.  The issue is totally random and when they are having an issue I can't even see the device trying to connect (by debugging the client on the controller).  One suggestion I've made is that we may need to upgrade the device firmware, but I'm not sure why it would work with the old controllers and not the new.  I guess the worst case scenario is that I can move the couple APs they have in the receiving area back to the old controllers to see if the issue continues.

I'm also seeing if anyone else has experienced a similar issue or might think of something that I might try.

Uggghhhhhh

Thanks all!

[daviwatk]

So you are most likely correct in that the "device" probably didn't goof up at the same time you moved APs from your WISM to your 5508.

Other than code, are you aware of any differences in your RRM configuration between the two?  It sounds like you simply do not have adequate coverage with your APs from what you describe.  Is it possible you had tweaked some of your RRM settings (TPC thresholds, etc) on the WiSM or even manually assigned power levels, etc, which is "not" being done on the 5508 by default currently.

Can you attach your "run-config" from the WLC.

1. >config paging disable

2. >show run-config

I would want to verify your AP power levels and look at your AP neighbor lists to see what your APs think they can hear nearby.

[Ryan Curry]

Thanks David, I looked at both controllers and can't see a difference in the RRM that would cause this issue.  I also went into WCS to the map containing the distribution area and performed a "View RX Neighbors" on them; it's showing between 66 and 75 dBm for the APs in the area.

Attached are compressed files of each run-config.

[Leo Laohoo]

These are b/g clients and I did diable all .11b data rates when moving to the new controller.

Can I ask if you ENABLE the 802.11b data rates, particularly the low-speed ones?

Can you verify that "Aeronet IE" is disabled?

[Ryan Curry]

leolaohoo wrote:
Can I ask if you ENABLE the 802.11b data rates, particularly the low-speed ones? 
Can you verify that "Aeronet IE" is disabled? 

Hi Leo, are you asking me to enable the b data rates?

Also, Aeronet IE is not enabled on that WLAN.

[Leo Laohoo]

Hi Leo, are you asking me to enable the b data rates?

Yes please.  I want to consider eliminating all the usual "suspects".

[George Stefanick · Accepted solution]

I've worked with these before. Are you sure they are bg? Mine are only b. put back your phy rates from the old wlc to the new wlc and I bet they start working ..

Sent from Cisco Technical Support iPhone App

[Ryan Curry]

Leo and George, thanks for the info; it appears that enabling the 5.5 and 11 data rates have fixed the issue (though the users won't call me back again to validate, but their silence is afirming).  What's odd is that these are the Dolphin 7850s which show they have a b/g card.  I suspect there may need to be a firmware update for these devices so that we can disable the b phy rates in our environment.

Thanks again to everyone for their input!

[George Stefanick]

Ryan,

Here is a little hint. If you know the MACs of the guns go to client view in the WLC and click on the MAC address. Check the PEM state towards the middle of the screen .. If its in run state, then you can confirm for sure life is good with them.

[Leo Laohoo]

When it comes to hand-held bar code scanners, in order to keep the costs down, the wireless card in them are mostly "made" 10 years ago.  Since the large data stream isn't really necessary then upgrading them to, for example, 802.11n is just foolish. 

[Ryan Curry]

George, I'll check that out; they see the issues sparatically so that's what made it so tough to track down.

Leo, I completely agree, these devices don't need anything more than a small data stream.  I want to remove all .11b phy rates from our environment and it seems these may be the only things holding me back from doing that.  To me, if the device has a b/g card then there should be no reason that it can't run at 6Mbps (right now I've only got 11 and 5.5 enabled on the b rates); hence why I'm hoping this is just a bug with the devices.

Thanks again!