This is a bit long and details a special case - sorry.
We had a disconnect (not a roaming) problem with ipod touch back in 2011/2012.
We bought 20 ipod touch 4g 8GB, to pilot test a guided tour for schools with a custom, non app store app, done by a 3rd party, who also set up the ipods.
The ipods were consistently disconnecting and not automatically reconnecting.
ZD1100 with 19 APs (7962 and 7363 at the time)
Don't know the firmware version but it was current at the time (march 2012); 9.3 something.
ios was 5.1 - we couldn't update it for "fear of breaking the app".
WLAN (for most systematic testing) was static channel 20Mhz, no encryption, no 5Ghz radio, L2/MAC access control, 7363 AP, ZD1100 as above.
Spent almost a week doing systematic packet capture and found:
- ipods disconnected consistently but not invariably after 30 minutes and could only be reconnected with manual intervention.
- disconnection could sometimes be mitigated by allowing a disconnect/reconnect
sequence at startup
(if not unlocked the ipods disconnect automatically after 30 seconds, then reconnect after unlocking).
- amount of udp/tcp network activity had no effect on disconnection after 30 minutes - no "keepalive"/inactivity effect.
(we used a modfied app version which sent a tcp packet every 2 minutes and arp,
dns lookup and multicast activity was also observed)
- the wlan had no internet access, but opening the wlan and allowing ipods to "phone home" had no effect on disconnection.
- testing was mostly with the ipods in one location connected to a single 7363AP where no roaming occurred. Moving them around and getting them to roam within the 30 minute window before disconnection had no effect. They behaved "normally"
- it was always the ipod that initiated the disconnection - never the AP.
- the behaviour of the ipods was the same in other non-ruckus wlans.
- 2 of the ipods did not exhibit the behaviour described and stayed connected
in all tested wlan environments.
- no other device (apple or otherwise) exhibited this disconnect behaviour.
Found a possible explanation why the interval before disconnection is 30 minutes
and was considering jail-breaking an iPod as a last resort.
Contribution by "wvcachi" Jun 8, 2010
If your touch is jailbroken, try this:
Use SSH or iFile to browse your touch's file system,
and go to var/preferences/SystemConfiguration and edit
the com.apple.wifi.plist file. Find the part that reads:
And change that 1800 to something much higher.
The number is how many seconds it will stay connected to wifi without its
being active (1800 is 30 minutes). I switched mine to 604800 - one week.
It could POSSIBLY be that that setting is what's causing your issue. Good luck!
<< Unquote >>
(The "without its being active" bit does not seem to be the case).
In our special case the ipods were the problem, not the network and before we sent 18 back to Apple, we finally found that the network state of the ipod at the
time the custom app was installed is key.
If it had no internet connection when the app was installed then the disconnect happened.
If it had an internet connection when the app was installed then it stayed connected.
So must/may be something to do with GUID checking of app/ipod/developer...
After reinstalling the ipods now work "as advertised"
Because the assumption was (always is?) "it must be the network", I had to spend a lot of time proving that it wasn't.