Hi,
thanks to the people from this forum I have configured my home network as one subnet for everything: one master router A (RB960PGS) and two WiFi routers B (962UiGS-5HacT2HnT, 2.4GHz and 5GHz ) and C (RB951G-2HnD, 2.4GHz) configured as bridges and connected via ethernet to A.

At this point B and C runs with separate SSID, so when I move from one part of the house to another, I need to change wifi network (SSID) so I have stronger signal. I understood from some other threads that it is possible to operate both overlapping wifi areas under same SSID but I didn't understand how to setup it correctly.

• Should I set same or different channels?
• How to include 2.4GHz and 5GHz interfaces from B? Just leave them in same bridge and change SSID?
• Do I need to set same security profiles?
• Is there anything else what I should consider?

Thanks!

Channels can and should be different if APs are within reach. Other config (SSID, password, ...) should be the same for all, e.g. same SSIDs with different passwords wouldn't work well. Someone who knows more about wifi than me can add more details.

Should I set same or different channels?

Channels should be optimal for the environment. Difficult to give a more directive answer. Maybe only one channel is really free. But there is absolutly no need to be on the same freq. If more than one channel is usable. Then it is preferred to use different channels.( cfr @Sob) Because if the same channel is used , everything will wait for air-time to transmit. Air-time can only be assigned once in a channel. (Any signal that is decodable (even when not usable for data transmission) will make others wait for air-time.) Client devices have no problem with roaming when different channels are used.

How to include 2.4GHz and 5GHz interfaces from B? Just leave them in same bridge and change SSID?

Leave them on the same bridge. Make all SSID identical between 2.4 and 5 GHz in A, B and C. (*)

Do I need to set same security profiles?

Yes , within the same MT just use the same security profile. Copy the security profile to the other MT.

Is there anything else what I should consider?

Well yes. Within 2.4GHz and within 5 GHz keep everything as similar as possible. E.G the 802.11 protocols used, the channel width.
Your setup is OK for the client devices to maintain their DHCP leased IP address. (They use the same DHCP server). This is essential !

(*) If there is a problem with client devices that flap between 2.4GHz and 5 GHz, then consider using or adding a specific 5GHz SSID name, that is only used for all the 5 GHz. [adding an extra SSID is by adding a "Virtual Wireless interface" with it's own SSID, extra WLAN is also to be connected to the bridge]

One more thing on client roaming. A client device will roam to any known or saved SSID if it loses contact. This might be very disturbing as that different SSID might be a different network, or require a different IP address. Not flagging "auto connect" for that SSID is not always enough. The only thing to do then is to "forget" the previous connected networks that are possibly in range. (But "open" networks may still be a problem with some clients that connect to whatever they see)

I have configured it and for now it works fine. Just need some more help with channels.

I made screenshots from WiFiAnalyzer app before I changed configuration where you can see both SSIDs (Raki-Trebo-2 and Raki-Trebo-Wrk-2) before I merged them. It seems they are runing on different channels so I let it untouched (Frequency = auto).

Screenshot_20220131-144047_WiFiAnalyzer.jpg

Screenshot_20220131-143801_WiFiAnalyzer.jpg

After merging into one SSID both APs runs on same channels. So I assume I need to change channels manually. Problem is I don't know how exactly. I see Frequency = auto in Interface/Wireless menu but I can choose only one selection if I want to change it. What relation is between frequency and channels? What should I set?

Screenshot_20220131-214737_WiFiAnalyzer.png

Wikipedia article with list of WLAN channels has list for 2.4GHz as well. In mikrotik you enter centre frequency. The list contains 20MHz channels, 40MHz channel is actually composed of two 20MHz ones with one of three layouts: Ce means frequency set defines lower half, eC means frequency set defines upper half and XX means device selects layout automatically.

In a AP-infested environment, such as your own, it is advisable to use 20MHz-wide channels (not 40MHz wide ones) in 2.4GHz band. It actually helps to get 3dB stronger signal (Tx power is spread over narrower band) and with lots of noise it helps to a more stable operation, many times even higher throughput.

This is general 802.11 info: You can find things like this: https://help.datto.com/s/article/KB1150 ... %205%20Ghz.

As you can see your own wifi environment is a big mess. This is very common! It is mostly due to using the "auto" channel setting.
Channels should not overlap. Therefore it is very common to use only channel 1, 6 or 11. But if others do not follow that rule channels overlap.(*)
(In Europe we could use 1,5,9,13 but as others use 6 and 11 even in europe it is seldom done)

So for channel use either ch1=2412, ch6=2437, or ch11=2462. Avoid using 40MHz , this is very wide and uses at least 8 channels as width.

(*) overlapping channels cause what is called "adjacent channel interference". Channels will NOT wait for each other but simultaneous transmission will cause destructive interference. The received packet will be corrupt, and both will have to send the packet again. but It may interfere again.
With exactly equal channel selections, we have "co-channel interference", actually co-channel coexistence, as all devices will wait for each other before transmitting. Only one can transmit at the same time, so they share the available air-time.
Co-channel is preferred above adjacent-channel.

@bpwl, @mkx, @Sob thank you for links and explanation.