Managed Cisco Access Points kicking devices off of wireless

[talksr]

Hi,

 

I am not sure if anyone can offer me some assistance on this..

 

 

School had been successfully using Apple Airports for WIFI for a number of years with all of their devices including iPads.

Recently switched to Cisco managed wireless and ever since, have had problems.

 

The main issue is as follows:

Wireless is dropping/flapping on devices, not because of weak signal but it seems inactivity.

 

If you unlock an iPad, you notice that the wireless is not connected.

A user must manually re-connect the device by visiting Settings>Wifi and re-inserting the password for wireless.

 

Once connected, the connection will be dropped after a time period of around 10 minutes if the device is not used or locked.

To re-connect the above process must be followed again.

 

Is this right?! Have never had this before, and have no access to the controller. The access point in question is a Cisco Aironet 2700 Series Wireless Access Point.

Does anyone with a Cisco AP know is there is a way to disable this feature?

Edited March 12, 2015 by talksr

[NB9457]

I'd get access to the controller, could be a number of things, couple that it could be:

 

-Wrong channels / interference

-They may have a sleep mode, not too sure

 

But the controller has a shed loads of options and it will be the best route of action to have a route in there.

[roadhouse1387]

I have built a lot of Cisco WLC wireless networks and have successfully deployed 1000+ ipads on the them with good results. However, i recognize your issue and I suspect whats happening here is that the ipad is either having trouble deciding if it should be using the 2.4Ghz band or the 5Ghz band or the signal is not as good as you are expecting and the ipad is jumping from one band to the other. I have seen this a lot with ipads. The roaming mechanisms are not really very good and they tend to hang on to weak signals rather than roaming when a better one is seen. That siad, its not always the ipad to blame, bad AP placement is equally a common cause i.e too many or not enough AP's in an area, but by far the bigger is low SNR caused by bad AP placement

 

You say you have good signal, do you know what that signal is in dbm ? and what your noise floor and resulting SNR is ? you should be looking for -65 min and about 20db snr. if you are outside this, then i would expect devices to start seeing either throughput or stability issues. It could also be plain old congestion if you have stacks of ipads on the 2.4ghz band. Check that out and then you could try band steering to push ipads onto the 5ghz band as its less congested.

 

2 simple things to check as well, check that you have configured you ipad to auto-connect when in range... a simple thing often missed and make sure you havent got 802.11n channel bonding enabled on the 2.4ghz band, its not really suported on the 2.4ghz as there are only three non-overlapping channels available so channel bonding effectively uses the whole of the 2.4 spectrum on a single AP leaving nothing for the other AP's (although you can turn it on and the WLC 'should' automatically disable it if it sees other AP's in the area).

 

drop me a PM and we can have a chat about it if it helps.

 

Cheers

[mhowell]

https://support.apple.com/en-bn/HT203068

 

The above Apple document makes interesting reading....

One common issues in schools is that there may not be enough "performance" coverage, certainly 5Ghz coverage, which the IPADS prefer.

A simple solution can be just displaying the SSID's you need only on the 2.4Ghz radio which forces the IPADS to connect to a 2.4Ghz (likely stronger) signal.

[roadhouse1387]

mhowell, that is an excellent document, thanks for sharing it. I have stuck it in my library :-)

 

 

I think though the answer would be to redesign, reposition or even add to, the AP inventory so that the 5ghz band is better propagated. The aim is to make use of the greater number of non overlapping channels (19 on band A and B for indoor use, as opposed to 3 for 2.4) thereby taking advantage of the considerable less congested 5ghz band. Also, channel bonding is really only available on the 5ghz frequencies so the extra throughput can be realized there and not on the 2.4. The band steering features of most controllers will help by actively encouraging clients to use the less congested 5ghz where its possible.