Wireless and RF

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Guru Elite

Re: Tough wireless coverage areas.


I have there isn't anything unusual about it. It's a good suggestion but I have worked with one very nice client who can't get good performance out of the room. The AP data is no different then where anywhere else. Maybe a higher number of CRC Errors and I have tons of data from that one client I could poor into this thread or with my TAC call but the issue remains the same. The user works great if they connect to the A radio. Very poor if they connect to the G radio.

Iperf tests are poor, and the spectrum is full of noise and high RSSI of outside interferers

Logic would dictate that if one area is bad and on the other side of the building its good there has to be something in the controller logs or the ap data. But I look at all ap's in the building and don't see anything, no common error, etc

I do

Show ap debug client table
show ap association ap-name
show ap debug system status
show ap arm rf-summary
show ap arum neighbours
show ap debug clien stats

and so on, thats cutting it short. Nothing really stands out. It's shaping up to be a dense deployment in a tough environment with a noisy 2.4ghz spectrum.




- When you say "dense environment", how many access points can you see from the location in question? Is it dense because there is some sort of interference or because you need capacity?
- Have you tried mode-aware ARM to reduce the interference introduced by additional coverage in the area?
- Since you have done spectrum analysis, what device did you do it with and how many non-wifi interferrers were there? - Have you ever done testing after-hours when there is little to no congestion?
- How many wireless networks are you broadcasting and what are there encryption types?
- Are you doing broadcast filtering on ALL virtual APs that access point is serving up?
- Are you doing band steering on all Virtual APs?
- How many people are on that access point on a regular day?
- Are there any errors on the switchport of that access point? Have they negotiated correctly? What about the port connected to the controller?

*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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Contributor I

Re: Tough wireless coverage areas.

Our environment has usually about 20 access points per building. Some have more, others a few less. They are spread out over 4 floors, with each having 5 or 6 access points on each floor. Roughly 15 to 20 feet apart. Each building is slightly different, and the buildings themselves are bunkers made of thick concrete.
Mode aware is something I’ve looked at by when AP’s go to air monitors some leave pockets of coverage holes. (AP70s and AP 125s) Also as I am not the Admin I don’t have the final say on turning that feature on.

I used the AirMagnet Spectrum Analyzer XT and each building has a high number of non-wifi interferers. Microwaves, 2.4ghz phones, xbox controllers, wireless cameras, and 2 possible interferers that put out a high signal across all channels but its not identified in the Airmagnet RF database. There is also a big number of users private SSIDS from users wireless printers. (Dorm environment.)

We are broadcasting only one ssid and it’s an open network. You don’t get access to the internet until your register your computer, where we have your ip and mac then you get a valid IP.

Broadcasting filtering on all virtual APs.
Band steering is done all on APs.

Each Access point can have anywhere from 5 to 20 clients on it depending on what time of day it is.

There are no errors on the switches and they all negotiate speeds correctly.
Guru Elite

Re: Tough wireless coverage areas.

Since your main issue is interference that you cannot control, bumping up the Non 802.11 Interference Immunity parameter could help, since you already have a dense deployment. Whatever it is on, you should move it up a click or two (once again, with the advice of TAC) and it should improve things, but decrease your coverage range. The goal is to only listen to traffic closer to the access point and be deaf to other traffic.

I would be most concerned about the wireless cameras and two interferers, because those can be very small, but cause a great deal of damage. Barring identifying and removing those devices when the dorms are empty, Non 802.11 Interference Immunity could be your only option on 2.4ghz. You can also consider upgrading your code for a better band steering algorithm to move devices that do NOT have to be on 2.4ghz off of it.

*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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Contributor I

Re: Tough wireless coverage areas.

Yeah TAC said don't go past level 3 if I am going to turn it up at all. Between that and placing the controller and access points off the same vlan the users use will hopefully help that last group of users having poor performance. Thanks for the time.