Dual wifi connections in Bookworm

If they are on the same frequency/channel, it’s no surprise they’re interfering with each other. Can you set them on different, non- overlapping frequencies/channels?

I wondered about that, but the initial settings were "automatic" and the connection software didn't try to put them on different channels. Presently the internal wifi remains "automatic" and the USB wifi is set to channel 5. At this point I'll be interested mostly in whether the setting is honored (tried it once before, still got channel 2).

There's still something funny about the two channels when used separately. The internal wifi shows ~5 ms pings to the access point with no other traffic but seconds of delay when watching Youtube videos. The external wifi alone shows ~2 ms delays when idle and only about 4 ms when watching YouTube. The internal wifi bogs down very badly under load, in a way that is new compared the initial Bookworm installation.

On the plus side, at least the internal wifi can connect now. For quite some time it didn't connect at all. I'm using the same hardware, only software updates have been applied.

Thanks for writing,

bob prohaska

I'm curious, what is the point? Do you want it to go faster, use a wire. Are you going to connect them to different access points? Do you have two different networks? You can plug in multiple USB NICs as well.

The point is to first understand why wifi connectivity went from usable to unusable. Then, if possible, to fix it.

The first thought was interference from other access points nearby. No consistent evidence has been found, but I'm still looking.

The second thought was a faulty upgrade to Bookworm (this is on a Pi5) There's a sliver of support for that idea, since performance changed following some upgrades.

Third, a problem with the access point. That seems unlikely since other hosts connect successfully and reliably.

Right now using a usb-wifi adapter seems to fix the problem. To me that suggests a problem with the internal WiFi hardware or the software that drives it. The Raspberry Pi forums have some accounts of poor wifi behavior on Pi5s, but not many and no unifying features are obvious.

Thanks for writing,

bob prohaska

What case do you use - is it metal? If so, I would suggest disabling the internal WiFi, and using the stronger signal you get from the USB adapter

Not metal. It's clear plastic. The internal wifi worked just fine, displaying signal quality in the 75-80% range when first set up.

There's some chance I misunderstand the meaning of "signal quality". It appears to be a simple log measure of received power. Maybe there's more to it. The man pages for wavemon don't indicate.

In effect, that's what I've done. I'd still like to understand why it was necessary.

Thanks for writing,

bob prohaska

Are you sure the unused interface is turned completely off -- no radio transmissions at all?

No, the only measure I have is wavemon running on the Pi5. It would be nice to ask the access point what it can see, but that feature is not offered, AFAIK.

When ifconfig takes the unused interface down wavemon stops reporting for it. At the moment there's a mismatch between what wavemon reports and what the GUI stataus indicator of the Pi5 reports. The latter states that both internal and external wifi interfaces are present and active, but ifconfig shows only the external wifi interface active with an IP number. The GUI indicator is also greyed out, as if historical.

Between what ifconfig reports and wavemon displays I tend to think the unused interface is inactive. However, I'm not certain.

Thanks for writing!

bob prohaska

Something else is going on. Placed in scan mode, the external usb-wifi adapter is reporting non-existent access points:

ATTKXEBVbA DC:8D:8A:5A:D6:D4 54%, -72 dBm, ch 1, 2412 MHz 43% chan, Radio Measure, Spectrum Mgmt d-link.zefox.net 00:13:46:86:6D:0C 96%, -43 dBm, ch 2, 2417 MHz ESS millerhome2 F0:72:EA:49:C6:4A 54%, -72 dBm, ch 6, 2437 MHz ESS, Radio Measure <hidden ESSID> 7C:9A:54:FC:7E:7F 70%, -61 dBm, ch 11, 2462 MHz ESS, Radio Measure, Spectrum Mgmt <hidden ESSID> 7C:9A:54:FC:7E:7E 70%, -61 dBm, ch 11, 2462 MHz ESS, Radio Measure, Spectrum Mgmt <hidden ESSID> 7C:9A:54:FC:7E:7C 71%, -60 dBm, ch 11, 2462 MHz ESS, Radio Measure, Spectrum Mgmt <hidden ESSID> 7C:9A:54:FC:7E:7A 71%, -60 dBm, ch 11, 2462 MHz ESS, Radio Measure, Spectrum Mgmt cross 7C:9A:54:FC:7E:79 71%, -60 dBm, ch 11, 2462 MHz ESS, Radio Measure, Spectrum Mgmt ATTKXEBVbA DC:8D:8A:5A:D6:D4 56%, -71 dBm, ch 36, 5180 MHz 20% chan, Radio Measure, Spectrum Mgmt <hidden ESSID> 7C:9A:54:FC:7E:87 60%, -68 dBm, ch 44, 5220 MHz ESS, Radio Measure, Spectrum Mgmt <hidden ESSID> 7C:9A:54:FC:7E:84 60%, -68 dBm, ch 44, 5220 MHz ESS, Radio Measure, Spectrum Mgmt cross 7C:9A:54:FC:7E:81 61%, -67 dBm, ch 44, 5220 MHz ESS, Radio Measure, Spectrum Mgmt <hidden ESSID> 7C:9A:54:FC:7E:86 63%, -66 dBm, ch 44, 5220 MHz ESS, Radio Measure, Spectrum Mgmt d-link.zefox.net 00:13:46:86:6D:0C 96%, -43 dBm, ch 108, 5540 MHz ESS d-link.zefox.net 00:13:46:86:6D:0C 97%, -42 dBm, ch 157, 5785 MHz ESS

The last two entries appear to be duplicates of the second, with a wrong frequency attribution: my AP can't use 5 GHz.

Anybody got an idea what's going on?

Thanks for reading!

bob prohaska

It must belong to a neighbor. My AP is d-link.zefox.net, a DI-524. What motivates the question?

Thanks for writing,

bob prohaska

That's a Nokia device. Possibly a smart phone being used as an access point

Thats a Pi set up badly

Those are all MAC addtreses from Vantiva, which sells broadband . Presumably they have some routers nearby

That's a Nokia device. Possibly a smart phone being used as an access point

More Manitiva s*it

That's a pi set up badly I think

I didn't see your access point in there at all.

What is its SSID?

And that is its SSID?

I didn't think you could put full stops in an SSID

Oh. The spec says you can. Other people suggest that some clients cannot deal with odd characters.

Please elaborate!

The MAC address is that of my access point, but that access point is limited to 2.4 GHz. The router supports only one LAN IP range AFAIK.

d-link.zefox.net I'm connected and typing via it now.

Thanks for writing,

bob prohaska

Sorry, but I still don't understand the significance of that fact.... Presumably a neighbor has the device, not me. Just to be clear, the table of signals is what my Pi could potentially connect to nearby.

Thanks for writing,

bob prohaska

If both interfaces are talking to the same Access point on the same frequency, it's going to be worse as WiFi can only talk to one thing at a time, and the two interfaces will compete for bandwidth.

If you set up the access point with a different SSID for each frequency, and connect an interface to each, you might get a small amount of additional bandwidth, but not a much as if you had two 5GHz access points on different frequencies and SSDs.

---druck

It's called logical deduction. You should try it sometime.

You can even put UTF-8 characters (like emojis) in the SSID (it's an extension, the AP must support that) - my guest network has those, and the clients I tested (Windows 10, Linux, Android) worked just fine.

cu Michael