I read that one must use the user/pass method of web auth to take advantage of the newer "sleeping client" functionality. Certainly the same need for this function applies to Passthrough (acceptable use page submission) authentication as well, since iOS and other guest devices leave and come back to the network frequently in some environments, regardless of whether they are issued a username and password or not.
Any idea why Cisco omitted the passthrough method for this functionality? Seems like it would be harder to code it out than in! I would think it to be a database of MAC addresses with a timer that resets any time there's activity from it. (Speaking of which, I'm really not sure why this feature has the "bytes" parameter... I suppose it could be useful, but most of the time "ANY" activity should do the trick... I just want to keep a device authenticated all day, regardless if the user wanders off campus for lunch or if his device drops into a sleep state.