On Mon, 9 Jan 2017 22:23:45 +0100 Linus Lüssing <linus.luessing@xxxxxxxxx> wrote: > On Mon, Jan 09, 2017 at 12:44:19PM +0100, M. Braun wrote: > > Am 09.01.2017 um 09:08 schrieb Johannes Berg: > > > Does it make sense to implement the two in separate layers though? > > > > > > Clearly, this part needs to be implemented in the bridge layer due to > > > the snooping knowledge, but the code is very similar to what mac80211 > > > has now. > > > > Does the bridge always know about all stations connected? > > The bridge does not always know about all stations, especially the > silent ones like in your DVB-T example. > > However, concerning IP multicast, there is IGMP/MLD. So the bridge > does know about all stations which are interested in a specific IP > multicast stream. > > (As long as there is a querier on the link, which periodically > queriers for IGMP/MLD reports from any listener. If there is no > querier then the bridge multicast snooping, including the bridge > multicast-to-unicast will fall back to flooding) > > > So if your television example uses IP multicast properly, it is > completely doable with the bridge multicast-to-unicast, thanks to > IGMP/MLD. I wonder if MAC80211 should be doing IGMP snooping and not bridge in this environment.