On Tue, Aug 12, 2008 at 8:42 AM, Jouni Malinen <j@xxxxx> wrote: > On Tue, Aug 12, 2008 at 02:40:23PM +0200, Helmut Schaa wrote: > >> JFYI I already started to rework the existing scan code in mac80211 >> (software scan) to do something like background scanning: >> >> 1) notify current AP about leaving the channel >> 2) scan one channel > > It might be useful to leave this "one" as a parameter to allow easy > experiments with scanning more than one channel at a time to reduce > latency. Ideally, this--along the interval for background scans--could > be something that is dynamically changed based on the expected traffic > pattern. Whenever there is lot of data traffic being (mostly > successfully) transmitted, it would be beneficial not to jump to other > channels as frequently or for as long a time. If there has not been any > data transmission for some time, it may be more acceptable to scan more > frequently and to remain away from the operational channel for longer > periods of time. Though, we should also keep in mind that background > scans are going to increase power consumption on otherwise inactive > situation, so setting a suitable policy for this can get quite complex. > > If we can somehow figure out whether there is periodic need for some > traffic (e.g., VoIP), it would also be nice to be able to schedule the > background scans to happen when there is no expected packet being sent > or received at the time. Obviously, this gets much more complex, so this > is not really something that would need to be included in the first > version ;-). Anyway, it would be useful to keep in mind that there may > be needs for making the background scan parameters change dynamically > and there is need to be able to configure a suitable policy from user > space. If someone is picking this up please extend our TODO list for roaming and mention it: http://wireless.kernel.org/en/developers/todo-list#Roaming Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
