Saturday, 20 August 2016

Maybe it was Unifi after all

DEAR PEOPLE FROM THE FUTURE: Here's what we've figured out so far ... (denvercoder9)

And another post on WiFi... The ongoing battle to stop our iPhones losing connection when roaming between Unifi APs.

The latest change seems to have worked. I really hope I am not coming back next week and updating this post to say otherwise. But really, it has been several days now, and no problem.

The change was to put the APs (Unifi AC Pro and AC Pro LR) on firmware

I had to change the controller to unifi5 to get this latest version

deb unifi5 ubiquiti

The iPhone is not off the hook entirely though - as even when it did not get DHCP and knew the WiFi was therefore not working, with a self allocated 169.254 address, it would still try and use the WiFi and not the 3G even with WiFi assist. So it was being dumb. But not as bad as I thought...

The other change in the latest firmware and controller that I have noticed is 14 more 5GHz channels, so 18 rather than just the 4 we had before. This will help avoid interference from other APs.

So, fingers crossed. This may be the answer.

P.S. One case of losing DHCP since...
P.P.S. Working quite well but has now failed a few times, so IS NOT A FINAL SOLUTION YET!


  1. Which 5GHz channels you are legally allowed to use varies by country. And I think in the UK you're only allowed to use 5GHz indoors, though how we're expected to stop it leaking out is a mystery to me. But anyway, before you select from all those extra channels, check if you're legally allowed to use them.

    1. You can use 5GHz outside just fine - in licenced bands and otherwise. You have to support DFS and there are power limits for different bands etc.

  2. Coincidentally I've been having problems with a Canon Pixma iP7250 having intermittent wireless connectivity since moving to using a Unifi AC-Lite AP. Upgrading to seems to have fixed this as well...

  3. Here's some info on the UK 5GHz bands

  4. There was an ios update in the last year which caused exactly the symptoms you described. I don't use ios but my daughter does and from memory there was a Unifi f/w update which fixed "intermittent loss of IP connectivity" which "fixed" that. 4.8.something was the controller update which bundled the f/w.

    The "new" 5GHz channels are there because Ubiquiti got the APs certified as suitable for use in Europe (EU anyway) - ie they proved that their implementation of DFS met the specs.

    Enjoy the luxury of your own 80MHz channel while it lasts - once the big ISPs get their routers certed then its going to be interesting.

    Worth noting that (in the EU) the 5GHz radio must listen for a minimum of 600 seconds for any interference (radars mainly) when you first use Band B (C100-C140). If interference is detected then the radio must switch to another channel.

    However, given the 10 minute dwell time when you switch between channels in Band B this is likely to result in pretty much every radio falling back to Band A channels (36-64) where DFS is not required.

  5. So, this is quite interesting (and your other posts on the matter).
    I'm curious, when a wireless client switches between ap's within the same SSID surely it would need to do a dhcp request, asking to retain its ip. (easily tested with other devices that work I guess) Otherwise how do the ap controllers know how to keep the clients working on the right ap.
    Reminds me of cell separation to a degree, so perhaps ubiquity have worked around it by allowing a device to move between ap's without this request for ip, it just uses existing Mac and ip table and allows it. (kinda like cam table lookups being refreshed)
    Therefor it makes me think Ubiquity have still worked around a client bug where the client doesn't request ip again.
    Should be easy to test the theory out I guess.

    1. The APs work at ethernet level, so controllers direct based on MAC not IP. I can understand devices not assuming the same SSID is the same network, but as you say, maybe keeping IP and requesting same IP is a good way to switch more seamless when they are on the same network. There are protocols for co-ordinating the handover with the APs though, as far as I know. I would not be surprised if there is a bug and workaround or some escalating deployment of new features that nearly work. Hard to tell for sure.

  6. My new iPhone 7 Plus is doing this constantly. Have you had the same? Once it's happened, what have you found is the best way to work around it so that you get an IP please?