[OpenWrt-Devel] [PATCH] ar8327: add IGMP Snooping support

Linus Lüssing linus.luessing at c0d3.blue
Fri Jan 8 18:14:14 EST 2016

On Tue, Jan 05, 2016 at 08:40:37PM +0100, Álvaro Fernández Rojas wrote:
> This add support for IGMP Snooping on atheros switches (enabled by default),
> which avoids flooding the network with multicast data.
> Tested on TL-WDR4300: disabling IGMP Snooping results in multicast flooding
> on each specific port, enabling it back again prevents each port from
> receiving all multicast packets.
> Partially based on: http://patchwork.ozlabs.org/patch/418122/
> Signed-off-by: Álvaro Fernández Rojas <noltari at gmail.com>


Do you know whether there is some documentation on what the IGMP
Snooping of these chips does?

For instance I'd be interested in knowing whether it takes
Multicast Router Discovery (MRD) into account. Does it
perform IGMP querying, too? Is there a maximum number of group
entries? Does it know both IGMPv2 and IGMPv3? No MLD support,

IGMP and IGMP snooping isn't that trivial. The IGMP snooping in
the Linux bridge took quite a while until it actually got usable,
too. So like Felix suggested in that ticket as well, I'd favor
disabling it by default. Especially if it is a blackbox without

Cheers, Linus

PS: Thanks for looking into improving the multicast experience
with OpenWRT :).
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