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Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

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  • 1.  Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Jun 19, 2023 04:18 AM
    Edited by MichaelM55 Aug 14, 2023 02:54 AM

    We´re using Aruba 802.11ax access points right from beginning in year 2019. Also we use IAP mode, i.e. local Aruba Instant clusters. Since around year 2021 one main feature is mentioned to be a "known issue" within the releases notes: Airtime Fairness. The bug is persistent in all 8.x releases:

    Aruba Instant 8.5.0.14 Release Notes
    Aruba Instant 8.6.0.21 Release Notes
    Aruba Instant 8.7.1.11 Release Notes
    Aruba Instant 8.8.0.3 Release Notes
    Aruba Instant 8.9.0.3 Release Notes
    Aruba Instant 8.10.0.7 Release Notes
    Aruba Instant 8.11.1.0 Release Notes

    I don´t know the reason for this, but I find it disappointing that Arubanetworks is unable to fix it. Running chargeable release 10.x is not an option, where this bug is not mentioned any longer.

     Airtime Fairness usage scenario:

    • room of 60 students / devices
    • Aruba AP-535 8.10.0.7
    • 29 clients connected at 867 Mbit/s @ 5 GHz, 29 clients connected at 433 Mbit/s @ 2.4 GHz
    • 1 client connected at 12 Mbit/s @ 5 GHz downloading gigabytes of data, 1 client connected at 12 Mbit/s at 2.4 GHz downloading gigabytes of data

    Of course it would have been great if airtime time "fair access" mode would work in such a situation.

    Let´s quote some other named vendor:

    "

    Why do we need Airtime Fairness?

    Traditionally, your phones, laptops, pads or any other devices need to compete for the chance to transmit and receive data when they are connected to the same Wi-Fi signal. In this situation, once a slow transmitting device gets the chance, it will take longer time to send or receive the data. In the meanwhile, other faster devices must wait until the slow device finishes the transmitting process. Based on the above situation, you might want to cut down time given to legacy devices to allow faster devices download data for longer times. This will significantly increase overall capacity of the network. To achieve such objective Airtime Fairness is introduced.

    How does Airtime Fairness work?

    Airtime Fairness feature is based on TDMA technology, short for Time Division Multiple Access. It divides the Wi-Fi signal into many same time slots, and each Wi-Fi device takes turns to send or receive data from the Internet within its own time slot. In this way, the capacity and efficiency of Wi-Fi will be improved.

    As shown above, without Airtime Fairness, those slow clients need more time to transfer the same data, which decreases Wi-Fi efficiency.

    With two different speeds of clients connected to the same Wi-Fi, the test result below shows us the improvement of Airtime Fairness. When Airtime Fairness is disabled, the download speed of 802.11g client is 28.075Mbps while 802.11n client is 18.521Mbps. But when Airtime Fairness is enabled, the download speed of 802.11g client is 12.214 while 802.11n client is 116.538Mbps, which is highly improved. The overall throughput of Wi-Fi has tripled (from 46Mbps to 128Mbps).

    "

    UPDATE 1

    ArubaOS 8.11.1.1 Release Notes

    Bug ID AOS-242732

    Instant 802.11ax access points experienced a noticeable performance
drop when the air-time-fairness setting was set to fair-access instead
of default-access. The issue was related to the air-time-fairness
feature not being compatible with modern APs. The fix ensures this
configuration does not impact newer APs negatively. This issue was
observed in APs running Aruba Instant 8.11.0.0 or later versions.
      • A bug with airtime fairness, first mentioned in release notes of year 2021, not in release notes from years 2019 and 2020 when Arubanetworks started selling its first 802.11ax access points. 

    Airtime Fairness, a feature which was once told us to work for Arubanetworks 802.11ax access points: https://community.arubanetworks.com/discussion/effect-of-airtime-fairness-mode-for-ac-and-ax



  • 2.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Jun 19, 2023 10:57 PM

    I think airtime fairness was more relevant when the client traffic mix had sizeable 11b clients, but for env these days where most of the clients wifi5/6/6E, airtime fairness would have very little impact.



    ------------------------------
    If my post was useful accept solution and/or give kudos.
    Any opinions expressed here are solely my own and not necessarily that of HPE or Aruba.
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  • 3.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Jun 20, 2023 02:41 AM

    I have to admit that I didn't expect an answer like this to come from an Arubanetworks employee...

    ... talking about a bug which exists for roughly 3 years

    ... talking about airtime


    Original Message


  • 4.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Jun 20, 2023 06:22 AM

    As I said, this is what I think not per say an official statement from Aruba.

    if this feature is a must have in your env, then please contact your local Aruba representative to explore what is possible. I am sure they could help escalate your TAC case.



    ------------------------------
    If my post was useful accept solution and/or give kudos.
    Any opinions expressed here are solely my own and not necessarily that of HPE or Aruba.
    ------------------------------

    Original Message


  • 5.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Jun 20, 2023 08:50 AM

    even I am also an Aruba Employee - this is not an official statement, only my sight to this.

    For me that is not a bug - which defines a defect in the Software - it is a Limitation - a function which is not implemented into the Software Release yet.

    The huge benefit of Aittime fairness was back in the days where you had 802.11b Clients in your environment.

    I have searched our RFE Tool (Request for enhancements) - which Partners and Employees have acces to and there is no demand for such feature.

    If you are a Partner, please insert you request and if you are an end customer, please talk to your Partner or Aruba representitive to file an RFE.

    What do you want to archieve with the Airtime fairness mode? Do you have any issues in your environment? Maybe this could source not in the lack of the Airtime fairness mode.

    Definition of Airtime fairness 

    The reason why it is not mentioned in AOS10 is because this is not existend. Because it makes in very little environments scenarios to zero environment scenarios sense. As said the Use-Case is so small and only in environments with very old Client Infrastructure from value. Those environments do not exist in a huge count.

    Most clients used as of today are 802.11n/ac/ax, very very little 802.11a/g/b (most of them are Barcode Scanner). What about your environment? What Client types are there?
    Starting from 802.11n Short Guard Interval was introduced and that was one of the reason for Airtime Fairness. To get "airtime fairness" with clients which are using Long Guard Interval (like 802.11, 802.11b/g/a)


    Original Message


  • 6.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Jun 21, 2023 09:24 AM

    Reading through this post has left me feeling sad.  

    Aruba was the best at wireless and had a very high quality product that was consistently improving.  Working with AOS10, TAC on support issues and reading these forums is leaving me concerned about the future/current state of Aruba.


    Original Message


  • 7.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Aug 11, 2023 04:12 AM

    My current speculation is that it might be a hardware problem. The chipset being used (and its firmware from the chipset vendor) is not capable of airtime fairness. Even no name vendors like TP-Link user e.g. Qualcomm FastConnect 6xxx chipset series for its WiFi6E access point and support Airtime Fairness.


    Original Message


  • 8.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Aug 11, 2023 03:52 PM

    "Airtime Fairness" was needed at the time, because wifi deployments were less prevalent and there was less access point density.  Wifi clients were also less capable so that the difference between the fastest client and slowest client was much greater than it is today.  

    These days, wifi is much more efficient, there is more density and clients are more capable, so the need for Airtime fairness in my opinion is much less if even at all.    A standard troubleshooting step in an environment is to turn off airtime fairness if enabled and design the network accordingly so that all clients get good performance.  After that, Airtime fairness (at least for the access points that support it) is not turned on again.

    You should open a support case and get an official answer.  I cannot remember the last time I enabled Airtime Fairness to solve a performance issue.



    ------------------------------
    Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.

    HPE Design and Deploy Guides: https://community.arubanetworks.com/support/migrated-knowledge-base?attachments=&communitykey=dcc83c62-1a3a-4dd8-94dc-92968ea6fff1&pageindex=0&pagesize=12&search=&sort=most_recent&viewtype=card
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    Original Message


  • 9.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Aug 11, 2023 03:56 PM

    I would say that the industry has moved and that is not what we see our customers asking us for.  Again, my opinion.



    ------------------------------
    Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.

    HPE Design and Deploy Guides: https://community.arubanetworks.com/support/migrated-knowledge-base?attachments=&communitykey=dcc83c62-1a3a-4dd8-94dc-92968ea6fff1&pageindex=0&pagesize=12&search=&sort=most_recent&viewtype=card
    ------------------------------

    Original Message


  • 10.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Aug 14, 2023 02:47 AM
    Edited by MichaelM55 Aug 14, 2023 02:47 AM

    ArubaOS 8.11.1.1 Release Notes

    Bug ID AOS-242732

    Instant 802.11ax access points experienced a noticeable performance
drop when the air-time-fairness setting was set to fair-access instead
of default-access. The issue was related to the air-time-fairness
feature not being compatible with modern APs. The fix ensures this
configuration does not impact newer APs negatively. This issue was
observed in APs running Aruba Instant 8.11.0.0 or later versions.

    A bug, first mentioned in release notes of year 2021, not in release notes from years 2019 and 2020 when Arubanetworks started selling its first 802.11ax access points.


    Original Message


  • 11.  RE: Long term bug: "Airtime Fairness Mode is not supported in 802.11ax access points."

    Posted Aug 14, 2023 06:21 AM

    The answer is not always as simple as what is written in publicly available release notes. Do you want this feature in your environment currently?  I think you should open a technical support case and get an official answer. 



    ------------------------------
    Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.

    HPE Design and Deploy Guides: https://community.arubanetworks.com/support/migrated-knowledge-base?attachments=&communitykey=dcc83c62-1a3a-4dd8-94dc-92968ea6fff1&pageindex=0&pagesize=12&search=&sort=most_recent&viewtype=card
    ------------------------------

    Original Message


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