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Comment by admax88q | Hacker News Reader

Traditionally roaming is left to the client device and most implementations are so bad that they won't give up on an old AP so long as they're seeing beacons every year or so. Who cares that I haven't successfully received a packet in the last hour, it's sure better than the 2 second interruption we'll get if we tried to switch.

I'm only mildly bitter at the useless roaming behaviour of most clients. Turning transmit power down doesn't really help either. Some clients will roam better but other clients at the edge of the coverage now have no coverage.

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Using software on my smartphone I can observe that it changes AP it associates with as I walk around the house where I have a “traditional” 802.11r WiFi network with common wired backend. No new DHCP is triggered either.

So it may not be perfect, but it can’t be that bad.

What do you use to verify which AP your device is connected to? I've not found a convenient way to do this for testing.

Net Analyzer for iPhone shows the raw BSSID (AP mac) for whatever network you connect to.

You need to know the MAC address of each of your access points - also known as the BSSID. It should be available in the admin UI of the access point, and sometimes also printed on a label attached to the AP.

Knowing that, you need something that shows you details about wifi connections, so you can view the BSSID (MAC address of the AP) you're connected to:

Android, iOS: Install the "Network Info II" app

Linux: use the iwconfig command

Windows: Use the command "netsh wlan show interfaces"

802.11r solves this. I’ve got it configured at my place and roaming is seamless and takes less than 100ms.

Can you elaborate on how you configured? What hardware are you using?

I had a few Devolo powerline adapters (which include a WiFi access point) and I reflashed the firmware with OpenWrt as a last resort (the default firmware didn’t support 802.11r and it was hell without it). Works great since then and it saves me from buying a set of enterprise-grade APs.

802.11r does not fix this. It makes the handoff slightly more efficient but the client still has to decide to actually do the handoff. And that's the part that never seems to happen, as many clients are stupid.

From my testing with iPhones, the stupid behaviour goes away on an 802.11r-enabled network. I noticed the same issues on a legacy network but that all went away after enabling 11r.

I would imagine that I phones has better roaming preference overall. But maybe having 802.11r enabled causes devices to be more optimistic in their roaming as they know they're not switching networks.

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