On my second cAP ax, the 5G radio won’t use the channel definition from CAPsMAN. Here, it’s set to use 5745 and 5805. The CAPsMAN host is using 5805, and the CAP is using 5240.
Moreover, I must update the channel definition to remove whatever random channel the CAP chooses, as both APs want to use the same frequency. That’s weird because the only 5G signals on the Freq Usage come from the other AP (I’m in a concrete bunker).
If I add 5200 to the channel definition, then CAPsMAN switches to 5200, and the CAP stays on 5240. At a width of 80 Mhz, they’re basically on top of each other:
The 5G radio on the CAP also stops accepting connections randomly, and all clients go to the 2G radio with the same SSID. I changed the SSID, appending “5G” to the name, to track when it stops talking to clients. I can’t see anything in the log, the interface status shows it’s running, but no clients will connect to it. I also don’t know why it starts working again. I fiddle with settings, reboot, etc., until the CAP chooses a new channel and clients connect to it again.
Have a good look at 5GHz channel list. As one can see, standard channel layout (including channel width) says that 5745 and 5805 at 80MHz wide channels overlap (as well), both are covering 80MHz channel number 155 (spanning between 5735 and 5815 MHz). So try to allow properly spread frequencies … and/or limit channel width to something you can afford.
The channel layout is important as well. In wifiwave2 is, unfortunately, not possible to explicitly set channel layout for 80+MHz wide channels, so essentially it’s a 20/40/80mhz-XXXX. But since driver tends to select some standard frequency channels, try to set allowed frequencies so that driver is forced to select Ceee layout. In upper part of 5GHz spectrum, that would mean frequencies 5745 and 5825 (the latter not being allowed as 80MHz channel in many parts of the World though). 5200 is not “Ceee” frequency either, 5180 is.
If your venue is essentially a reinforced concrete tomb, why are you limiting frequency range to only a narrow part of spectrum available?
When MT wifi driver is allowed to autoselect frequency, it does some quick sweep over those frequencies, then it selects one of least used. And after that it tends to stick to selected frequency quite a while. The problem with CAPsMAN-controled wireless network is that controller may request frequency reconfiguration from all CAPs at the same time. During channel reconfiguration, AP stops to transmit and does the measurements. If all CAPs do it at the same time, then none of them are transmitting and all see whole spectrum to be free. And it does seem that MT favours lower frequencies (there are a few good reasons for that, one is that all 5GHz clients support them as lower part was standardized for wifi use earlier, another reason is that allowed Tx power is highest, allowing for best WiFi signal coverage, etc.).
This means that it’s good to create two frequency channel groups (with non-overlaping frequencies) and provision CAPs into alternate frequency channel groups so that adjacent CAPs don’t belong to same channel group.
Yeah, this isn’t the original, well-defined scheme. At this point, I’m throwing in bands to see if something will work.
If I set no frequency range, or if the CAPsMAN AP doesn’t crowd out those higher channels, then the second AP uses 5885, and no clients will connect to it.
And then if I have the CAPsMAN take the last freq block, then the CAP picks something else, and clients can connect again:
For testing, I have a client that can only see CAPsMAN, a client that can only see CAP (opposing sides of a thick ol’ bank vault), and my cell phone I can watch roam between them.
The highest part of 5GHz spectrum was added to wifi spectrum fairly recently. Not all devices support it (either their hardware can not work with such high frequencies or their firmware was not updated with new channel layout and/or country regulatory limits). So as a rule of thumb: whenever clients seem to struggle connecting to those channels, reconfigure AP to only use channels from UNII-2 or earlier. (and beware that UNII-2C channels come with burden of DFS, so even in your concrete bunker there will be 1-minute or 10-minute periods of no 5GHz wifi signal when/if AP decides to change frequencies)
From the channel list on wikipedia follows, that 5745 Ceee is 80MHz channel #155 and 5885 eeeC is channel #175, so they are different (in addition, channel #175 seems to be illegal to use anywhere but in USA).
There are (many?) station devices which don’t like channel layouts other than those with C in lowest part of channel, for 80MHz channel that means Ceee. Since it’s not possible to set channel layout explicitly for wifi(wave2) driver, you can only affect that by selecting frequency properly (e.g. 5500 or 5580).
BTW, inability of clients to connect to AP uding 5885 might be due to clients not knowing that 5885 is legal and they refuse to “see” it. Years ago I had problems when a brand new, out-of-the-box, phone LG G4 did not “see” wifi operating on 2.4GHz channel 13 (it’s legal in ETSI countries but not in USA). After I inserted SIM card allowing phone to register to mobile network, phone figured it was in ETSI country and it now started to see wifi AP.
No, they’re adjacent 80MHz channels. 5745 Ceee spans from 5735 to 5815 MHz and 5885 eeeC spans from 5815 to 5895 MHz. If you want to configure these two in Ceee both, use 5745 and 5825 as frequencies.
Yes, sorry. I meant 5825 Ceee and 5885 eeeC are the same Freq range. The only way I can prevent the other CAP from using 5885 is if I set CAPsMan to use 5825. And using 5825 all three clients connect without a problem.
I’ll have to return them at this point. I don’t know how anyone gets WifiWave2 CAPsMAN to work, but I have spent a considerable amount of time trying to figure it out and cannot find any help addressing the issue.
Even though the config and channel settings were configured the same for wifi1 and wifi2, the CAP ignored anything that wasn’t set in the config section for wifi1.
