Should I name the SSID the same name for the 5ghz and 2.4ghz radios, or keep the names separate?
Does anyone know the pros and cons? I have a google home, with smart lights, chromecast, etc, and I want those devices to automatically be able to talk to one another.
I too never found anything concrete to explain this either. I’ve run previously with separate ssid and now with them the same. Only difference seems to be you only need to enter the password once from client devices. I could never find a way to reliably test client devices switching from one radio to the other. But from what I found last year it’s highly dependent on the client devices on when and at what thresholds they will switch to the other radio. I never found any official standard on it either - it seemed to be one of these pseudo standards that all manufacturers have kind of added support for.. although there are enterprise level standards for roaming between ap devices fwiw
It's basically a matter of personal preference, but…
If you use the same ESSID/ PSK on both bands, the clients may make smarter decisions for roaming between them - and you can further help the clients (only rather new/ highend ones though) by optimizing this further via IEEE 802.11k/v/r.
If you use different access credentials per band, it's easier for you to distinguish between them and to force your clients to your preferred band, neutering any automated (advanced) roaming decisions your clients may (or may not) be able to do.
Hostapd can do some band-steering on the AP side by denying authentication to 2.4G if clients have been recently associated to 5G, but it requires that the two interfaces be run on one instance/service of hostapd.
The framework for netifd/hostapd/mac80211 is already there: http://lists.infradead.org/pipermail/openwrt-devel/2019-November/019978.html
Guess we'll just have to wait when they flip the switch to a single instance.
Ah, so OpenWrt doesn't do band-steering right now? Is it just a random assignment? or is it just whatever the client chooses?
So right now, hostapd can only run as two instances, one per interface?
Yes, to both of your remarks.
Well, the assignment isn't random, OpenWrt offers both equally - leaving the decision which band to use to the client.
The modern clients are pretty smart about choosing a proper band and I found wifi more reliable, because a laptop is always connected to a good signal. This also means that it might delay a fallback to a strong 5GHz if it is already connected to strong 2GHz. But if 5GHz is deteriorating, then a switch over to 2GHz is pretty fast.
I think I noticed that mobile devices switch over to 2GHz when sleeping (to preserve battery?) and then to 5GHz when they wake up. I now use the same name for both bands, because it works well.
You can configure two BSSIDs in each band: one with the same name, for clients that can choose by themselves, and another one with different names, for clients that must be tied to an specific band.