On 2017-01-11 13:15, IgorMitsyanko wrote: > On 01/11/2017 02:30 PM, Felix Fietkau wrote: >> On 2017-01-11 12:26, IgorMitsyanko wrote: >>> On 01/11/2017 12:27 AM, Felix Fietkau wrote: >>>> On 2017-01-10 11:56, Johannes Berg wrote: >>>>> On Tue, 2017-01-10 at 05:18 +0100, Linus Lüssing wrote: >>>>>> On Mon, Jan 09, 2017 at 01:30:32PM -0800, Stephen Hemminger wrote: >>>>>>> I wonder if MAC80211 should be doing IGMP snooping and not bridge >>>>>>> in this environment. >>>>>> In the long term, yes. For now, not quite sure. >>>>> There's no "for now" in the kernel. Code added now will have to be >>>>> maintained essentially forever. >>>> I'm not sure that putting the IGMP snooping code in mac80211 is a good >>>> idea, that would be quite a bit of code duplication. >>>> This implementation works, it's very simple, and it's quite flexible for >>>> a number of use cases. >>>> >>>> Is there any remaining objection to merging this in principle (aside >>>> from potential issues with the code)? >>>> >>>> - Felix >>>> >>> >>> Hi Felix, can we consider two examples configurations with multicast >>> traffic: >>> >>> 1. AP is a source of multicast traffic itself, no bridge on AP. For >>> example, wireless video server streaming to several clients. >>> In this situation, we can not make use of possible advantages given by >>> mc-to-uc conversion? >> You could simply put the AP interface in a bridge, no need to have any >> other bridge members present. >> >>> 2. A configuration with AP + STA + 3 client devices behind STA. >>> ----|client 1| >>> | >>> | mc |----|AP|----|STA|---|---|client 2| >>> |server| | >>> ----|client 3| >>> >>> Multicast server behind AP streams MC video traffic. All 3 clients >>> behind the STA have joined the multicast group. >>> I'm not sure if this case will be handled correctly with mc-to-uc >>> conversion in bridge on AP? >> What do you mean by "3 client devices behind STA"? Are you using a >> 4-addr STA, multicast routing, or some kind of vendor specific "client >> bridge" hackery? > > 3 client devices connected by backbone Ethernet network. Generic > case is probably STA/AP operating in 4-addr mode (more or less standard > solution as far as I know). If the AP is running in 4-addr mode, it will need to have a bridge interface anyway, because the link to the STA will be split out into a separate virtual interface (AP_VLAN iftype). In this case you don't actually need any multicast-to-unicast conversion, because the multicast traffic will be unicast on 802.11 already (due to use of 4-addr mode). - Felix
