Controllerless Networks

Hello,

I noticed a strange behavior in a part of our building, We have IAP 207 connected to an AirWave server (activity monitoring) after receing many users complain they have been disconnected from Skype meeting, or other application, i had a look into Airwave logs and notice despite the computer (client) doesn't move (user stay at his desk or in meeting room) his computer, without any reason, decide to change and connect to another AP, firdtly connected to the closest AP, the computer disconnect and connect to the upper floor, and few minutes after go back to the closest AP, and go back the the upper floor ...

Don't know what's happend, it's not only one user, it happens to many peoples. If anybody could help me to find what's going wrong, it would be really appreciated !!!

Thanks 

Olivier

Do a proper survey and check the coverage. May be access points were installed very  close to each other or transmt power is high.

Better open a tac case and they will tell you the exact reason for this behavior. 

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@Olivier_1968 wrote:

Hello,

I noticed a strange behavior in a part of our building, We have IAP 207 connected to an AirWave server (activity monitoring) after receing many users complain they have been disconnected from Skype meeting, or other application, i had a look into Airwave logs and notice despite the computer (client) doesn't move (user stay at his desk or in meeting room) his computer, without any reason, decide to change and connect to another AP, firdtly connected to the closest AP, the computer disconnect and connect to the upper floor, and few minutes after go back to the closest AP, and go back the the upper floor ...

 

Don't know what's happend, it's not only one user, it happens to many peoples. If anybody could help me to find what's going wrong, it would be really appreciated !!!

 

Thanks 

Olivier

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Two "possible" reasons why a station that is not moving roams:

- The transmit power is too high on access points and the client will go from high-powered AP to the next high-powered AP

- Too much cochannel interference, so if a client on another AP, that is on the same channel transmits alot of data, the strong connection of the first client becomes unusable and that client will roam (hidden node issue).

The solution is to find out what band the client is on when it has issues and see how much overlapping cochannel interference there is.  If it is on the 2.4ghz spectrum, consider lowering the max transmit power for that band.

If it is on the 5ghz spectrum, see if you can run 40 or 20mhz channels, or add channels to your regulatory domain..

Thanks for your answer, i checked the ARM setup, Min transmit power=12 Max Transmit power=18 looks correct for me.

How can i identify cochannel interference level in Airwave ?

That power range is a good starting point, but could be too high in some circumstances.

What is your channel width on the 5ghz band?

On Airwave, each access point has a radio hyperlink, one for the 2.4ghz and one for the 5ghz.  What is the RF utilization at peak on the 2.4ghz band for the access points that are having problems?

What band are the clients on that are having problems?

Do you have broadcast filtering on all of your SSIDs?

5Ghz Channel width : 80 Mhz support enable

What is the RF utilization at peak on the 2.4ghz band for the access points that are having problems? In Airwave i can get few data on AP radio, usage from/to client in Kb=>  is it this Indicator ?

Client problem occured on 2.4G but also on 5G.

Broadcast filtering is set to : ARP

Okay.  You should uncheck 80mhz channel support.  By default, an 80mhz wide channel plan only allows for two channels, which can produce alot of cochannel interference.  Unchecking 80mhz  would allow at least 4 channels and give you some more bandwidth on the 5ghz band.  You could also optionally uncheck Wide Channel Bands to go down to 20 mhz channels which would give you 9 non-overlapping channels.

Monitor your network after any changes.  Also determine if there is anything that you can replicate at will so we can know the result of the changes.

Can you show in airwave what screen you are talking about?

Thanks for your advise, i unchecked 80mhz channel support.

See below an Airwave Screenshot (may be i'm not in the correct Airwave screen).

You are in the right screen.  Change the dropdown from usage to channel utilization and post that screen.

Here is

Your channel utilization should drop to zero when there is nobody around.  Since your channel utilization is close to 25% minimum, you should try lowering your 2.4ghz maximum transmit power by three.  That AP had 5 or fewer people and alot of cochannel interference.

ok, i understand.

So i'm going to setup the Min transmit power to 3 and Max transmit power to 9.

This setup will be Apply to all AP 2.4 and 5G of the Instant network, i guess.

I don't see where i could apply it only to 2.4G and specifics AP. 

Use "customize power range setting" to configure the 5ghz separate from the 2.4ghz:

https://www.arubanetworks.com/techdocs/Instant_85_WebHelp/Content/instant-ug/arm/conf-radio-sett.htm

Many thanks for all !!!

i applied recommended setup, we'll keep an eye on interference level.

Olivier