[pim] Issues with MLD and Android powersaving / sleep mode...

Linus Lüssing <linus.luessing@c0d3.blue> Tue, 24 March 2020 20:54 UTC

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From: Linus Lüssing <linus.luessing@c0d3.blue>
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Subject: [pim] Issues with MLD and Android powersaving / sleep mode...
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With Freifunk [0] we lately came across an annoying issue with Android
devices... which I'm not really sure how to solve yet...

It seems that (some?) Android devices do not respond to MLD
queries when in sleep mode:


Which causes severe IPv6 connectivity/usability issues
when trying to use MLD snooping capabilities.

As soon as you turn on the screen of the Android device or
connect a charger MLD Reports arrive just fine. My test results
were, as noted in the Android ticket:

Results with phone on battery:
* 0/8 MLD Reports received
* 3/8 Neighbor Advertisements received
* 8/8 Echo Replies received

Results with phone on charger:
* 8/8 MLD Reports received
* 8/8 Neighbor Advertisements received
* 8/8 Echo Replies received

Fixing this on the Android devices would need several years to
propagate, as noted by an Android dev.

Has anyone on this list experienced similar issues, too? And is
there maybe even someone who came up with a workaround that they
implemented on the router/switch side?

If not and if we can't come up with a solution it looks pretty
gloomy for (non-flooding) multicast in wifi networks to me for
the next years...

Regards, Linus

[0]: https://freifunk.net/en/