My AppleTV doesn't like WPA2

Update Oct 2010: Seems the latest Airport software resolves these issues, see related post - AppleTV + WPA2 redux

So I scored a 500GB Time Capsule for Christmas to replace the old 802.11b/g Airport Express we’ve been running for the past couple of years. Primary reason for upgrading was to remove the need to have a drive plugged into the MBP to run Time Machine with the added bonus of removing some cable clutter from the desk in the process. The changeover was not without issues, issues which took a fair bit of time & frustration to eventually resolve.

The trouble was that once installed and after upgrading the home WiFi network to use the faster 802.11n protocol, our AppleTV started playing up. iTunes on the MBP could see the AppleTV and was syncing to it without any problems (in fact sync speed was positively screaming compared to the previous “G” network), the issue was that when we tried to watch any video on the TV, the picture would stutter, perpetually attempt to buffer video and generally just sucked. Music worked fine, trailers worked fine, the problem seemingly only existed for movies streaming from iTunes.

So I did what any (in)sane person would do: changed the wireless channel; performed a factory reset on the AppleTV; unlinked and relinked it to iTunes; switched off Time Machine; changed back and forth between a 2.4Ghz 802.11a/b/g/n and 5Ghz 802.11n network; upgraded my router’s firmware; performed a factory reset on the router; switched off NAT and DHCP on the Time Capsule and made it into a bridge; all to no avail. It seemed like a WiFi bandwidth issue, I just couldn’t get the root cause.

After searching the outer limits of the Internets and beyond, then delving into some murky “support” forums and generally tearing my hair out, I ended up reading the ‘Troubleshooting’ section of the AppleTV user manual, like any good user should. There on Page 29 was the smallest ray of hope:

“If security is enabled on the network, temporarily disable it on the base station and try connecting again.”

As soon as I did this, streaming worked perfectly. I switched security back on and the streaming issues returned.

Now at this point I was running the full-hog 5Ghz 802.11n which on the Time Capsule happens to only support WPA2 security, albeit in a choice of either “WPA2 Personal” or “WPA2 Enterprise” flavours. Seeing as I’m not an “Enterprise”, Personal was the only way to go and unfortunately one that seemed to be interferring with streaming. So I downgraded to 2.4Ghz 802.11b/g/n mode, switched out to “WPA/WPA2 Personal” and bingo - everything just worked™.

Shame that I can’t take full advantage of 270Mb/s 802.11n WiFi, though 130Mb/s is still plenty fast enough whilst also still allowing my iPhone to access our home network.

Anyone else having these issues with WPA2 security & AppleTV streaming on their “N” Airport Extreme or Time Capsule?