Wireless Access

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Guru Elite

Re: Issue w/ Low Goodput Numbers on 3400 Series Controller/AP225s

- I am not sure how channel busy is reported when channels are bonded.  It is possible that reading is not representative of all channels when reporting more than a single channel together.

- Theoretical achievable data rates are based on how many channels are bonded, the capability of the client and the capability of the access points.  Please see the rate charts here:  http://community.arubanetworks.com/t5/Unified-Wired-Wireless-Access/TUTORIAL-ArubaOS-6-3-and-Above-802-11ac-Enable-VHT-even-if-you/m-p/142739

- Actual rates depend on distance, contention with other clients and potential interference in the space.  Many of the higher rates are heavily dependent on close distances to the access points.  As clients get further away from access points, their negotiated rates go down, as it becomes more difficult to send packets successfully at higher rates.  Other clients that may or may not support 80mhz or even 40 mhz channels also consume part of the medium and could make an 802.11ac client de-rate if it cannot gain access to the medium in a specific amount of time.  Non-802.11 Interference can also cause a client to de-rate, due to the fact that transmissions are unable to complete the first, second or third time successfully.  In general, it takes more time and effort for a client to increase its rates, after de-rating that it does to de-rate.

- If you have mixed clients (AC and non-AC) and density, it is sometimes advisable to start with 20mhz channels because (1) It is the lowest common denominator for all clients (2) You have more available channels, so the likelihood of access points with overlapping channels next to each other is decreased (3) localized interference could potentially be avoided or worked around (4) 802.11ac clients will still be able to transmit at higher rates, even with 20mhz channels (4) In a mixed environment, it is statistically more likely to be able to transmit successfully at range with 20mhz channels.

 

*Everything mentioned above is theory geared towards deployment strategy assuming that most client deployments will be mixed and somewhat dense.  It is also fairly conservative.   There is nothing wrong with tuning things to get better results, because every deployment is different.


*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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Frequent Contributor I

Re: Issue w/ Low Goodput Numbers on 3400 Series Controller/AP225s

Thanks again for the info. And I totally agree with your point regarding tuning. I know the capabilities of the Aruba Ap225s. I'm certain that with more tuning, I can improve overall performance from 11ac and 11n clients connected to the AP225s. 

 

I'll follow-up with the Aruba TAC regarding Bonded Channels. There is still something not 100% right with the Ap225s and the very low Goodput %s 'From Client' compared to 'To Client' reported in the dashboard. Although, I'm getting different numbers when I pull up To/From Client Stats. Plus, I'm starting to see an increase in dropped frames to the client, which could be related.

Anthony
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Frequent Contributor I

Re: Issue w/ Low Goodput Numbers on 3400 Series Controller/AP225s

Thanks again CJoseph for the recommendations and advice! 

Anthony
Super Contributor II

Re: Issue w/ Low Goodput Numbers on 3400 Series Controller/AP225s

Your problems very much sounds like the environment suffers from alot of co-channel contention. Evaluate that using 80mhz channels only leaves you 4 non overlapping channels to play with.

 

If you´re using dynamic channels with ARM, In the controller you can use "show ap active" to verify the spread of channels and choise of power levels

 

Also try "show ap arm neighbors ap-name" to get a feel of how good the APs can hear eachother (through walls and floors). I´ve seen many environments with so much leakage that the only sensible thing is to use 20mhz channels and shut down alot of 2,4ghz radios. (I usually put mode-aware on and limit the 2,4ghz radio to 9-12dBm.)

Christoffer Jacobsson | Aranya AB
Aruba Partner Ambassador
Aruba: ACMX #537 ACCP ACDP | CWNP: CWNE #306
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