Open Radar

 
Summary:
Regularly but, frustratingly, not 100 % so, when one certain iPod Touch device enters the range of our AirPort TC Wifi and shakes hands with our guest Wifi, the TC base station becomes unresponsive: it displays an “all OK” green light and the Wifi is nominally up, but Internet connectivity is gone for all devices on the network and the base station is not listed in AirPort utility anymore. The station only starts responding again after being rebooted the hard way (A/C disconnect and reconnect).

Steps to Reproduce:
The bug is reproducible on our own network (always the same device, always the same crash, on different dates and between TC reboots), but YMMV:
1. set up a 4th gen TC AirPort base station as follows:
— Make sure you are using Firmware version 7.6.4 (upgrade if not);
— Configure main Wifi to use 802.11.a/n / 802.11b/g/n auto mode, channels 8 and 48, 5 GHz network name shadowing, region: Germany;
— Activate guest Wifi;
— Set the SSID for both networks in E-Mail address format, leave it visible;
— Set WPA2/AES (aka “personal WPA2”) security with separate passwords: 50 random chars and digits key for main Wifi, 15 chars and digits phrase for Guest Wifi.
2. Get a model MD723FD/A iPod Touch, making sure it runs iOS 7.0.6 (11B651).
3. Connect the iPod to the guest (not main) Wifi.
4. Physically leave Wifi range with the iPod for at least 24 h, keeping the main Wifi network in intensive use by at least 4 iOS and OS X devices (that’s our home network config — I *said* YMMV).
5. Physically re-enter Wifi range with the iPod.
6. If station does not crash, repeat steps 4 and 5.

Expected Results:
Network connectivity fort the iPod.

Actual Results:
AirPort crashes and burns (figuratively), taking down the whole network in flames — see introductory para.

Notes:
Regular devices on the network: one early 2013 iMac 21" running OS X 10.9.2, one late 2006 iMac 21" running OS X 10.8.5, one late 2006 MacBook running OS X 10.7.5, one 1080p Apple TV running the most current firmware update (could look it up, but I’m lazy), one iPhone 5 running iOS 7.0.6, one iPhone 4S running iOS 7.0.6, one iPhone 3GS running iOS 6 latest iteration, one iPad 3 running iOS 7.0.6, one AirPort Express (FW 7.6.4) in receiving mode (used for audio AirPlay only).