Channel Width (wifi-qcom-ac)

RouterOS Wireless Networking
1

Hi all,


two weeks ago I upgraded my five mikrotik aps to v.7.13.x and switched to the new wifi-qcom-ac package.
Apart from the need to reconfigure my vlan tagging everything went smooth.

I’m pretty satisfied with the performance so far, but one aspect keeps me wondering just if somethings wrong with my configuration.

This is an excerpt from one of my access points (redacted the SSID):

/interface wifi security
add authentication-types=wpa2-psk,wpa3-psk disabled=no group-encryption=ccmp group-key-update=20m management-encryption=gmac-256 management-protection=allowed name=PSK-LAN wps=disable
add authentication-types=wpa2-psk,wpa3-psk disabled=no group-encryption=ccmp group-key-update=20m management-encryption=gmac-256 management-protection=allowed name=PSK-Guest wps=disable
add authentication-types=wpa2-psk disabled=no name=PSK-IoT
/interface wifi
set [ find default-name=wifi1 ] channel.band=2ghz-n .frequency=2472 .secondary-frequency=disabled .width=20mhz comment="2,4 GHz LAN" configuration.country=Germany .mode=ap .ssid=LAN \
    disabled=no security=PSK-LAN security.authentication-types=wpa2-psk,wpa3-psk steering.neighbor-group=dynamic-LAN-7ca1688e .rrm=yes .wnm=yes
set [ find default-name=wifi2 ] channel.band=5ghz-ac .frequency=5300 .secondary-frequency=disabled .width=20/40mhz-Ce comment="5 GHz LAN" configuration.country=Germany .mode=ap .ssid=LAN \
    disabled=no security=PSK-LAN security.authentication-types=wpa2-psk,wpa3-psk steering.neighbor-group=dynamic-LAN-7ca1688e .rrm=yes .wnm=yes
add comment="2,4 GHz Guest" configuration.mode=ap .ssid=Guest disabled=no mac-address=2E:C8:1B:xx:xx:xx master-interface=wifi1 name=wifi3 security=PSK-Guest \
    security.authentication-types=wpa2-psk,wpa3-psk steering.neighbor-group=dynamic-Guest-64eec2f9 .rrm=yes .wnm=yes
add comment="5 GHz Guest" configuration.mode=ap .ssid=Guest disabled=no mac-address=2E:C8:1B:xx:xx:xx master-interface=wifi2 name=wifi4 security=PSK-Guest \
    security.authentication-types=wpa2-psk,wpa3-psk steering.neighbor-group=dynamic-Guest-64eec2f9 .rrm=yes .wnm=yes
add comment="2,4 GHz IoT" configuration.mode=ap .ssid=IoT disabled=no mac-address=2E:C8:1B:xx:xx:xx master-interface=wifi1 name=wifi5 security=PSK-IoT \
    security.authentication-types=wpa2-psk steering.neighbor-group=dynamic-IoT-492e1712 .rrm=yes .wnm=yes

So my channel/frequency plan on 2.4 GHz is as follows:
ap1 - channel 1
ap2 - channel 5
ap3 - channel 9
ap4 - channel 13
ap5 - channel 1

This configuration obviously only works in countries which allow the use of channel 13 (which is the case in germany).
But heres the catch: Before the change to wifi-qcom-ac the channels were 20MHz wide (as per configuration) and did not overlap.
Since the upgrade the channels seem to occupy 40MHz even if I configured them to be 20MHz wide (see config above).

Attached is a screenshot of LinSSID showcasing the problem. I checked before and after the switch to wifi-qcom-ac and this problem only started after upgrading from the old wireless driver.
channel-overlap.png
Any Ideas? Possible Bug in RouterOS? Possible Bug in LinSSID?
What do you think?


regards from germany

  • kk1992
2

Please write to support@mikrotik.com and send us supout.rif file from one of the APs. We will take a look. Is “LinSSID” reporting 5GHz frequencies correctly for you?

3

I will send an email right away.
Yes, LinSSID reports the correct 5 GHz frequencies.

  • kk1992
4

What devices do you use?
What width is reported in on the WiFi tab in WiFi?

5

3 * RBwAPG-5HacD2HnD (wAP AC gen2)
1 * RBD52G-5HacD2HnD (hAP AC2)
1 * RBwAPGR-5HacD2HnD (wAP R AC)
all running ROS 7.13.3 and Firmware 7.13.3


20MHz, as is configured

  • kk1992
6

Just installed LinSSID cause I was curious too.

LinSSID reports 40MHz bandwidth here too. I too have configured 20MHz channel width on AP.

But the android app “analiti” says it is 20MHz.

Who is right? Most likely LinSSID is wrong.

I have different devices and different platforms (MacOS, Android, Linux) and all report 20MHz.
2024-02-09_18-05.png

7

might i suggest Nir Sofer’s “WifiInfoView”?

this will decode the 802.11 beacon, like wireshark would, but with a much simpler setup :

https://www.nirsoft.net/utils/wifi_information_view.html

8

Your screenshot also shows “b” protocol on channel 100 and “ac” on channel 6. This is obviously incorrect.

9

:rofl::rofl::rofl:

Even the reported signal is not reflecting the reality.

10

Ok, so LinSSID doesn’t seem to keep up with wireless technology…

Any suggestion for a good 802.11/wifi analyzer running on Linux?

The only remaining mystery:
Why was LinSSID reporting the correct channel bandwidth utilizing the old wireless driver?
Nevermind, LinSSID seems to be abandoned by it’s developer.

\

  • kk1992
11

If you have Android device you can try with WiFi Analyzer

12

Maybe:
https://github.com/ghostop14/sparrow-wifi

Cannot say how well it works, but the sheer idea of running it on a pi carried by a drone is IMHO a sign of genius.