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Posts: 9
Registered: ‎06-28-2017

5GHz Disappears

[ Edited ]

Hi All,

 

Trying to understand/solve a 5Ghz dissapearing issue.

 

I have installed many home wifi networks (over 50 homes) over the past few months and have realized I have a very specific issue that keeps repeating itself in many of the homes.

 

Currently I mostly use WAP750AC Acces points used in "Access Point" mode which are wired to the central router. Unfortunaly our home here are build with lots of hi density concreate and lots of steal reinforcement and so signal quality from one room to the next is very poor at the best of times. Thus we use multiple access points on the same floor in different rooms to make sure we have a consistant 5GHz coverage. We avoid 2.4GHz due to high home cluster building and too much cross channel interfernce from all the homes having big routers trying to boost signals everywhere (you can see most of the time over 50 wifi networks when using a "Wifi Analyzer"). 2.4GHz is only used when 5GHz is not possible. For 80% of the cases this works 100% and performance is amazing.

 

Now for the issue. If you have too many AP's in close proximity (about 3 AP units needed to covery weak spots), then from time to time the 5GHz radio with shutdown (dissapear) on the AP's (sometimes all and sometimes only individual AP's). What I have found is if I change the channel width from "Auto" (which mostly runs at 80MHz width) down to 40MHz width on all the AP's, then the 5GHz is stable and we have no issues.

 

Then recently we started using the RE6500 (with new 1.07 firmware can be used a "Access Point" mode) in combination with the WAP750AC's as the RE6500 gives us a few switch ports for wired devices. Now the above problem is worse and need to switch the channel width to 20MHz. In 99% of the time this will work but still have the occasional 5GHz dissapearing and need to restart the AP's.

 

Some points to consider which I need to mention:

  • This problem does not seem to happen on other brands (so far we have not seen this but not saying it is impossible to not have the same issue)
  • We are already using as little as possible AP's per home (please dont tell me we are using too many and must use less - less does not give us enough coverage on dead spots)
  • We have the problem when using WAP750's only, so not because of different models.
  • Seems somhow to be mostly home with IOS devices having this issue (but hard to eliminate due to vast number of user devices)
  • 2.4GHz and 5GHz have different SSID's
  • Lastest firmware installed on ALL the devices.

 

My question is:

  • Why does this happen?
  • Does the unit have this functionality to shutdow 5GHz radio or is this a bug?
  • Is it normal or only on Linksys?
  • Can this be fixed on firmware level?
  • Is anyone else having the same issue?

Sorry for the long message but need to try be very clear on the problem.

 

Thanks

Expert
Posts: 13,604
Registered: ‎01-18-2013

Re: 5GHz Disappears

[ Edited ]

RaymondS wrote:

 

My question is:

  • Why does this happen? It could be that the "auto" channel setting is force the APs' to change to a channel that doesn't work in the locations country code. Another thing could be that you are setting all APs' to the same channel when specifying channels. I recommned alternating AP channels frequency by distance suing 2.4Ghz channels 3,6 for 40Mhz and 36,149 for 5Ghz 80Mhz.
  • Does the unit have this functionality to shutdow 5GHz radio or is this a bug? AFAIK it only has the capability to change the channel in "auto" channel setting or if another FCC rule forces it to change like the 40Mhz co-existense rule which will auto drop the 2.4Ghz to 20Mhz if a SSID with 40Mhz is detected or DFS change channel on radar detection.
  • Is it normal or only on Linksys? I think these days it happens with most manufactures except those that ignore the FCC rules.
  • Can this be fixed on firmware level? Yes but you are already running the latest firmwares for your hardware. The WRT1900ACS router will allow you to use the advance open source firmware LEDE\OpenWRT, DD-WRT and McDebian for fine control over it's firmware and advance features. I've implemented WRT1900ACSs' with McDebian so I didn't have expensive licensing cost and the flexibility to do what I want with the unit. If your customer can afford expensive hardware and yearly licensing feases the Cisco Meraki would be best for those very rich.
  • Is anyone else having the same issue? I don't see many reports of the WAP750AC or RE6500 having this issue in the forum with there recent firmware releases.

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Communities Technical Support
Posts: 9
Registered: ‎06-28-2017

Re: 5GHz Disappears

Thanks for the reponse. Trying to give more info below:

 

  • Why does this happen? It could be that the "auto" channel setting is force the APs' to change to a channel that doesn't work in the locations country code. Another thing could be that you are setting all APs' to the same channel when specifying channels. I recommned alternating AP channels frequency by distance suing 2.4Ghz channels 3,6 for 40Mhz and 36,149 for 5Ghz 80Mhz. Current channel width set to "auto", but have tried setting to specific channels and still have same issue. Unfortunately cannot control the other 50 wifi networks in the area and so "auto" seems to work best. 2.4GHz never dissappears. Always there but not 5GHz, has a mind of its own. Forcing 5GHz to 20 MHz width so far works the best but not for too long and then it will dissappear (dissapears anything between 10 minutes and sometime 2-3 days. So not consistent)
  • Does the unit have this functionality to shutdow 5GHz radio or is this a bug? AFAIK it only has the capability to change the channel in "auto" channel setting or if another FCC rule forces it to change like the 40Mhz co-existense rule which will auto drop the 2.4Ghz to 20Mhz if a SSID with 40Mhz is detected or DFS change channel on radar detection. Agree that DFS could force a channel change but dont think router will do a auto width change. Never seen the width adjust once the radio is up and working. Still, this might have more to it and the device could have something in it to shutdown. I know that DFS switch channel is originated but the DFS service and so did not think AP's could talk to each other in this way. Thought they on listen for this DFS interruption.
  • Is it normal or only on Linksys? I think these days it happens with most manufactures except those that ignore the FCC rules. Strange that I dont seem to have the problem on TP-Link in the few installations I have done. But hard to say as 90% installations are Linksys
  • Can this be fixed on firmware level? Yes but you are already running the latest firmwares for your hardware. The WRT1900ACS router will allow you to use the advance open source firmware LEDE\OpenWRT, DD-WRT and McDebian for fine control over it's firmware and advance features. I've implemented WRT1900ACSs' with McDebian so I didn't have expensive licensing cost and the flexibility to do what I want with the unit. If your customer can afford expensive hardware and yearly licensing feases the Cisco Meraki would be best for those very rich. Would love to have clients that have "Rich" budgets. I have a full Ubiquiti network in my home (secure gateway, managed switch, Pro AP's) and it simple amazing performance. But to expect normal home users to spend roughly $100 more per access point would not be feasible especially in homes where I have used up to 6 AP's.
Expert
Posts: 239
Registered: ‎10-13-2006

Re: 5GHz Disappears

Which firmware is running on WAP750AC?

Posts: 9
Registered: ‎06-28-2017

Re: 5GHz Disappears

Version: 1.2.02.002

Posts: 10
Registered: ‎11-01-2017

Re: 5GHz Disappears

 

I am having this problem also.   The 5Ghz band either drops power or dissapears all together if I have it set to 80 Mhz with AC.  If i drop the band to A/N only (so no AC) then it becomes stable.

 

I have done wifi analyser test to make sure there are no other routers/APs using the same channels.

 

 

 

Posts: 10
Registered: ‎11-01-2017

Re: 5GHz Disappears

OK well it seems to be stable using AC but only if I manually select a channel/frequency.

 

Bit strange that AUTO doesn't work but oh well ....

 

Posts: 9
Registered: ‎06-28-2017

Re: 5GHz Disappears

Manually selecting a channel/frequency does work sometime but have found that also to fail.

 

I am working with Linksys trying to get them to solve the issue but as no one so far can replicate the problem consistantly, so to have they not been able to replicate.

 

Where are you located and how many AP's are you using on the same network?

Posts: 10
Registered: ‎11-01-2017

Re: 5GHz Disappears


I am in the United Kingdom and using a Virgin Media Superhub 3 (200 Mbps service) as my main router.
The RE6500 is hardwired to the above by CAT6.

So far (with the channel set to 48) it's seems to be stable.
Posts: 9
Registered: ‎06-28-2017

Re: 5GHz Disappears

RE6500 has two issues accourding to me. 

 

  • Dissapearing 5GHz
  • Radio restart after wired divice connects or disconnects

 

Would be interesting if you are experiencing the second point as well. Please have a look at the videos in this link and let me know if you can replicate the second point:

 

(Sent private message with Google link as I cannot do it here)

 

Here in Middle East we face this problem on all RE6500's with SKU "ME".

 

As for the WAP750AC, same issue for dissapearing 5GHz.