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Wifi Drop Out

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31 Mar 2020 10:00 #95860 by peter-l
Wifi Drop Out was created by peter-l
Hi Folks,

I was hoping some of you wireless gurus can help me troubleshoot this issue. My devices seem to drop wireless connection, i'm not sure if they are jumping channel or between 2.4 or 5ghz. Though when I've been testing i'm sitting about 3 metres direct line of sight from the 2925vn+ (issue happens on Mobiles & Laptop) - Wired connection has no issues.

I have 1x Draytek 2925vn+ (3.8.9.7) and 1x Draytek AP-902 (1.3.1)
I have 2x SSID's both broadcasting on 2.4 and 5ghz, 1 is isolated (member), the other (for guest) is not isolated.

Channel selection is set to Auto for the Router & AP. AP is using a WLAN profile.

I appreciate there are quite a few more settings that I need to provide, but if anyone could help I will happily provide more information to help get to the root of this issue.

Thanks!

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01 Apr 2020 02:38 #95867 by hornbyp
Replied by hornbyp on topic Re: Wifi Drop Out

Peter-L wrote:
I'm not sure if they are jumping channel or between 2.4 or 5ghz.


Install Draytek's SYSLOG server from here: https://www.draytek.co.uk/support/downloads/software/send/336-software/1697-syslog-458-win and point your devices at it. This is where the error messages and debugging information appear :wink:

And he" wrote:
I have 1x Draytek 2925vn+ (3.8.9.7) and 1x Draytek AP-902 (1.3.1)
I have 2x SSID's both broadcasting on 2.4 and 5ghz, 1 is isolated (member), the other (for guest) is not isolated.
Channel selection is set to Auto for the Router & AP. AP is using a WLAN profile.


You don't say how these are connected...hard-wired as two separate Access Points, or is one a Repeater/Extender for the other?

What's the objective? Seamless roaming or something else?

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01 Apr 2020 08:24 #95868 by peter-l
Replied by peter-l on topic Re: Wifi Drop Out
I'll try and get the syslog server setup at the weekend.

The 2925 and 902 are connected via 1Gbit cable and the aim is seamless roaming / better coverage (I think that's how they are configured). However the drop outs happen even when the device is static, approx 3m from the 2925

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01 Apr 2020 15:55 #95872 by hornbyp
Replied by hornbyp on topic Re: Wifi Drop Out

Peter-L wrote:
I'll try and get the syslog server setup at the weekend.



It's not as complicated as it sounds :)

  • Download package and install.

  • Fire it up and say "Yes" to the Firewall alert (to allow UDP port 514 in).

  • On both Draytek's, Enable Syslog and enter IP address of machine it's running on.

  • On the AP902 you choose the "Log level", on the 2925 you choose specific things to log.



I must say - having embarked on a similar exercise earlier in the year, after moving house - I don't rate your chances of achieving what you want to do :( . I ended up going down the Wired, Mesh Wifi route.

The main problem, is that WiFi clients don't do what you'd expect, i.e. continuously scan for the best signal. They tend to hold on to what they've got, till they finally lose connection. The "Assisted Roaming" feature can be used; this encourages them to leave - but they often just come back. In the (Draytek) mesh setup, the APs decide which is the best one to service the client - then use a combination of temporary blocking and disconnecting, to encourage them to move (you can see this happening via Syslog). There is also support for 'cached credentials', which lets the roaming process occur very quickly.

In addition to Syslog, there are some other tools in your armoury.

  • Enable "Developer Mode" on an Android device (google for method). If you're lucky, you'll then find a "Enable Wi-Fi verbose logging" option. On most devices, this now shows you which specific AP you are connected to and the signal level you're achieving. (As you'll have discovered, with two APs and two wireless bands, it's normally as clear as mud!)

  • Try one of the "Wifi Analyser" type apps on Android. This will let you see the relative signal strengths of neighbouring APs, and where there are gaps you can exploit. (Older versions of Android are better for this - later ones are restricted as to how often they can scan)

  • Turn off "AUTO" channel selection and choose your own, based on the output of aforementioned analysis. At the very least, your own AP's should be on different channels. On the 5GHz band, watch out for the use of channel no. > 52, where you're likely to invoke the "Radar detection" ... where everything plays dead for 10 minutes. The AP902 has an "Interference Monitor" in the "diagnostics" section, that can suggest the best channel to use.

  • Consider the physical location of your AP's.

  • Have a play with the "Band steering" and "Assisted Roaming" parameters (using your Wifi Analyser app for guidance). I found the default parameters were nothing like aggressive enough to encourage switching to a better AP. In a mesh configuration, these can be very aggressive, because they only get invoked if there is a better option.

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02 Apr 2020 09:00 #95876 by peter-l
Replied by peter-l on topic Re: Wifi Drop Out
Thanks, I'll have a read over the Mesh Wifi config and see what all is involved.

I also had a chat with support and they did a remote session and changed a few settings (mostly with the channels used) and it seems to be much more stable since.

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