Problems with Channels automatically changing

dcshobbydcshobby Member Posts: 20
Hello. We received our first Xi-2 AP to play with and we are running the latest firmware version which is 1.0.0.0.31 or at least that's what it was after a firmware upgrade showed it was available from the Harmony AP.

The main problem I'm having is that the AP is changing channels automatically and frequently enough that we receive 10-15 seconds of packet loss during channels changes when on 5GHz and ping spikes when it changes on 2.4GHz. It is changing channels on the 5Ghz side every 20-30 seconds and is switching channel sizes from 20 to 40 mhz channel sizes as well. I am connecting using my mid-2013 MacBook air and have plenty of data to show the AP is changing channels and we're receiving 100% packet loss (complete stop of traffic) during the channel change. I have not experienced this on our Ubiquiti UniFi AP that we've had in place for the last year.

Let me know what kind of data you need to help troubleshoot this as this type of performance is unacceptable and will not work for us or our customers. To give you an idea of our environment, this is in our rural country home over a half mile away from neighbors and we can see no other networks when we bring our devices outside even so the spectrum is very clean and the AP should not have to change channels all the time.

Comments

  • ericsrericsr Member Posts: 457
    Hi @dcshobby‌. Welcome to the family and thanks for your comment. We have a dynamic channel selection process that is very "noisy" in the first few hours. This allows it to properly sample the environment to make the best decision. It will cool after about 2-4 hours, but we also support 802.11h which notifies the clients of the impending change. You can certainly assign a static channel to avoid this process. Hope this helps.
  • dcshobbydcshobby Member Posts: 20
    Will this happen every time the AP boots up or just the first time it is powered on? I'm thinking after a power outage or firmware upgrade that if this happens each time one of those events happens, we will have this frequent downtime while it scans channels. This is not exactly what we like to see.

    Checking now again, my Macbook is connected to Channel 3 in 2.4ghz instead of in the 5ghz band where it should be with the band steering feature.

    Also, can you set the auto feature to ONLY allow it to choose channels 1, 6, 11 instead of every channel inbetween? No point in congesting two channels by picking channel 3 for example when there are only 3 non-overlapping channels in the 2.4ghz band so it should stick to 1,6,11

    Thank you
  • ericsrericsr Member Posts: 457
    @dcshobby‌ Yes, this process does happen with each reboot, but we hope this will be very infrequent. There is a reason to use channels other than 1,6,11 so don't believe the hype. :) Slightly detuning your frequency can have a huge performance improvement when in the presence of adjacent channel interference. Band steering can only do so much and it does not force you to 5GHz. Its ultimately a client decision. We will make tuning adjustments to the channel selection algorithm based on feedback and testing so I appreciate you reaching out to us.
  • dcshobbydcshobby Member Posts: 20
    Do the AP's send out statistics and usage information to Xclaim to help make these future adjustments? Kind of like Apple diagnostic on the iPhone sending back log information, etc.
  • ericsrericsr Member Posts: 457
    No, they do not. You can use our forums to request and report issues as well as what works well. We will make changes based upon user requests. I promise you that.
  • josejose Member Posts: 68
    edited November 2014
    @ericsr‌ now that we are talking about automatic channel selection. This is for the Ruckus ZD. I usually just enable channels 1, 6, 11.
    On a noisy environment, Would I see any improvements if I enable all the channels?
  • ericsrericsr Member Posts: 457
    @jose‌ Absolutely. With an advanced algorithm like ChannelFly, the more channel options the better. Good luck!
  • formarishkaformarishka Member Posts: 5
    Hi Eric!

    I'm testing Xi-3 at home, real problems with auto channel selecting.
    Channels were changing so fast, that I barely had time to change the settings to use static channel..
    See my ping statistic
    So, at this time DCS is really unusable =(
    By the way, I think that AP must choose only between 1,6 and 11 in 2.4 band (in DCS mode), because co-channel interference is better than between neighboor channels. Good document about this - http://www.cisco.com/c/en/us/td/docs/wireless/technology/channel/deployment/guide/Channel.html
  • ericsrericsr Member Posts: 457

    Hi Eric!

    I'm testing Xi-3 at home, real problems with auto channel selecting.
    Channels were changing so fast, that I barely had time to change the settings to use static channel..
    See my ping statistic
    So, at this time DCS is really unusable =(
    By the way, I think that AP must choose only between 1,6 and 11 in 2.4 band (in DCS mode), because co-channel interference is better than between neighboor channels. Good document about this - http://www.cisco.com/c/en/us/td/docs/wireless/technology/channel/deployment/guide/Channel.html

    Dynamic channel is a statistical model that requires collection prior to making accurate adjustments. This is a learning process and this happens for the first 6-8 hours and will start to settle as it gets enough information. There is no reason you have to pick 1,6, and 11 only. Many reasons for slight detuning will increase performance. If this process does not work, then simply make a selection manually. Thanks!
  • formarishkaformarishka Member Posts: 5
    Eric, thanks for answer!
    So, I'll wait for 6-8 hours, then AP will choose clear channel (for example, channel 6).
    But what will happen when my neighboor will decide to change his AP also to channel 6? Xclaim AP will notice this and start new learning process?
  • ericsrericsr Member Posts: 457

    Eric, thanks for answer!
    So, I'll wait for 6-8 hours, then AP will choose clear channel (for example, channel 6).
    But what will happen when my neighboor will decide to change his AP also to channel 6? Xclaim AP will notice this and start new learning process?

    This is the whole point of dynamic channel selection. It needs to adjust to real time interference. We do something most vendors do not, 802.11h CSA, which means we notify the clients of the impending change. Not all clients support this on 2.4GHz but almost all have to on 5GHz. Dynamic Channel will not work in all cases and in some very small setups (homes, low interference, etc) it might be best to set channel manually.
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