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thn80
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WiFi - When to use "main interface", when to use "virtual interfaces"

Sun Feb 19, 2023 5:52 pm

Hi,

please apologize for my - maybe stupid - beginner question.
I would like to configure a Guest WLAN and later maybe some further WLAN networks (with further SSIDs). My hAP ac² provides two "main" wireless interfaces ("wlan1" and "wlan" with 2.4 GHz respectively 5 GHz).
If I setup my first WLAN, should this be done as a "virtual" interface below one of the main interfaces or should I directly configure it on the "main" interface without a virtual interface?
In case I would do it via a "virtual" wireless network, what to configure on the "main" interface for the SSID and Security Profile, for example? At the moment I highly assume that at a first step the "main" interfaces should be used and virtual interfaces should only be added if both main interfaces are already occupied with other SSIDs. Is there a good tutorial for beginners on this topic?

Thanks a lot in advance,

Thomas
 
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rumahnetmks
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Sun Feb 19, 2023 6:12 pm

In my network I always set "main" or MASTER Interface (wlan0, wlan1) as "always on MyMainNetwork SSID".
Guest network should be at virtual wlan interface created with pair of its MASTER Interface.

Let say
wlan0 = 5Ghz
wlan1 = 2.4Ghz
with SSID MyMainNetwork, set its Main address, DHCP, etc

then for Guest
I will create
wlan2 Virtual Access Point 5Ghz, set Master Interface wlan0
wlan3 Virtual Access Point 2.4Ghz, set Master Interface wlan1
with SSID MyGuest, set its Guest address, DHCP, etc
 
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mkx
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Sun Feb 19, 2023 9:15 pm

It doesn't matter which SSID is on master and which on slave. The important things are the following:
  • All properties of "physical" radio (frequency, channel width, AFAIK wifi generation (i.e. A, B, G, N, AC, ...) as well, etc.) are set only on master interface, slaves inherit them
  • every slave can be disabled without effect on other slaves and master. If master is disabled, then slaves go down with it.
  • It might be possible to set-up master without setting security properties (SSID, PSK, etc.) and exclusively set those properties on slaves but if my memory serves me right, things don't behave nicely then.

When configuring AP which uses wireless for uplink connection, the decissive factor is the first bullet ... only master can be set as wireless client to another AP because only master is able to follow radio parameters changes, mandated by AP.
 
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thn80
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Tue Feb 21, 2023 11:30 pm

Is there any (performance) drawback of a virtual slave interface, compared to the performance of a main interface?
 
pe1chl
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Wed Feb 22, 2023 1:09 am

No, but there IS a definite performance drawback of setting several slave interfaces on a master.
Each slave transmits its beacons, and that takes airtime.
When you just want to put one or two fixed clients into another network, it can be more efficient to use the (MAC-based) access list to define a VLAN tag.
(or in a more complex network use RADIUS-based WPA2-EAP authentication and assign the VLAN using RADIUS based on the credentials)
 
prmfeddema
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Wed Jun 07, 2023 11:01 pm

Well - i went ahead and defined 6 virtual AP's in total (3 on 2.4GHZ and 4 on 5GHZ) - and things did not work very well - i had to disable a few to get things working again.

I wonder whether it makes sense to ensure that the total combined channel width of the virtual AP's is equal to the base channel width (or close to that, in any case my virtual AP's inherited all from the base channel (hence all 80mhz wide) - but it seems that throught the configuration tab you can reduce that ?
 
holvoetn
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Wed Jun 07, 2023 11:02 pm

Slave will always follow master for radio settings.
 
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Amm0
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Wed Jun 07, 2023 11:17 pm

Every additional SSID decreases performance, so reducing the number SSID needed is what helps performance.

e.g. If your goal is "cleanup the config" by using only virtual SSIDs... that's not a good idea.
 
holvoetn
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Wed Jun 07, 2023 11:27 pm

For fun, here is a MUM presentation of mAP Lite with 8 SSIDs :lol:

https://mum.mikrotik.com/presentations/ ... 179397.pdf
 
pe1chl
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Thu Jun 08, 2023 12:28 am

Every additional SSID decreases performance, so reducing the number SSID needed is what helps performance.

e.g. If your goal is "cleanup the config" by using only virtual SSIDs... that's not a good idea.
Indeed! I cleaned up my config and have only a single SSID now with mac-based assignment of VLAN, so I still have a total of 5 networks that can be accessed.
Initially I had problems, but setting the multicast helper to "full" instead of "default" fixed that.
 
t0mm13b
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Re: WiFi - When to use "main interface", when to use "virtual interfaces"

Thu Jun 08, 2023 12:29 am

FWIW, I have 3 virtual AP's on VLAN's, on 5Ghz along with primary AP, and a guest Wifi VLAN on primary 2.4Ghz, and no discernible differences with streaming and general internet access. :D

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