Wireless Access

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Re: Avoid interference on same channel

I would get an eval version of Airwave and target the RF Heatlh report and the RF Capacity dashboard.  Let it run for a few days and look at the data.  It should give you a good indication of what's happening.  I think it's safe to lower from 15 to 12 dBm for min TX EIRP.  If you then look and see that ALL APs (2.4 radio) have tuned down to 12, then you may even be safe to lower to 9 in select spots.  

Seth R. Fiermonti
Consulting Systems Engineer - ACCX, ACDX, ACMX
Email: seth@hpe.com
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Frequent Contributor I

Re: Avoid interference on same channel

Here's to get an idea of how our RF coverage and how our environment.

Thx

MVP Guru

Re: Avoid interference on same channel

 

You may have an issue because all those APs are in the hallway and they can hear each other too much vs if you had them inside the offices.

 

Whats the structure of those walls ?

 

Thank you

Victor Fabian
Lead Mobility Architect @WEI
AMFX | ACMX | ACDX | ACCX | CWAP | CWDP | CWNA
Frequent Contributor I

Re: Avoid interference on same channel

Victor, 

All possible and imaginable as glass, concrete, marble and plaster walls. This is the great challenge.

In the latter case the idea is to reposition these points Justamante access in the rooms, but I want to minimize as much as possible before reposition them.

Re: Avoid interference on same channel

You can also turn-off 2.4 GHz band on few AP`s by doing AP-specfic to avoid too much coverage after being done with the site-survey.

 

Thx. 

Frequent Contributor I

Re: Avoid interference on same channel

Sriram,

One idea would be that, thanks for reminding, after a survey if I have an acceptable coverage but can turn off some radios 2.4, transforming them in monitor this frequency.

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Frequent Contributor II

Re: Avoid interference on same channel

"You may have an issue because all those APs are in the hallway and they can hear each other too much vs if you had them inside the offices.

 

Whats the structure of those walls ?"

 

 

^^ This!!!  We have an extremely dense deployment of Aruba with 4 of our sites having over 250+ AP and 3000+ clients daily in each.  Here are some suggestions I would make.

 

Don't let APs see each other directly if possible.  This means putting them in rooms and not hallways.  When they are in the hallways, you get several bad things: users are on the other side of the wall(s) so they get reduced signal, APs will turn power down (see first point), interference indexes calculated by ARM will be higher than normal thereby adding possible issues with ARM, etc.

 

Turn off at least 1/3 to 1/2 of the 2.4ghz radios (site survey needed for specifics).

 

Turning off HT-40 really helps in many ways (you've already done that).

 

Be careful with adjusting power levels.  Try to keep power levels fairly close for max/min.  We go as low as 9/6 in our 'ballroom' while some high density areas are 12/9.  Our normal levels are 18/15 for the 4 really high density sites mentioned above.  If you use a larger spread, say 18/12 then some APs will be 18 while many are 12... this causing a clumping of clients trying to get on the AP with power level 18 (it can happen but may not).

 

If you start lowering power levels then consider removing some lower data rates.  This is an art more than a science so lots of testing will be required.

 

Get the Aruba document(s) regarding how ARM calculates interference indexes (intf_index).  You can figure out a great deal with that information.  You will be able to determine when an AP should change channels and what channel it would probably change to as well.  Airwave can help with visuals as well.

Trusted Contributor I

Re: Avoid interference on same channel

Any updates on this?  I'm going through a similar exercise and it would be nice to know how you tackled the problem.

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Guru Elite

Re: Avoid interference on same channel

thecompnerd,

 

The solution to any problem is site-specific.  If you could tell us your building construction, how far apart your access points are spaced, your user patterns and how many SSIDs you have, that would be a start.  Others can give you ideas, but not all would be applicable to your situation.


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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Occasional Contributor I

Re: Avoid interference on same channel

Hi,

I think my question is closely related to the subject.
I am looking for a report or a command whihc will indicate areas with interference (APs on the same channel); we do have a lot of Aruba APs and some standalone AP on ADSL lines. ARM is sometimes limited by user connected and might have even left no choice by surrounding APs.
I would like to help ARM by reconfiguring standalone APs ; but like I have mentioned; need to have indication of those areas first.
thanks.

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