wake on lan / wol with linux in IPv6-LAN (without IPv4)

[Mikael Abrahamsson]

On Tue, 16 Sep 2014, Tom Hill wrote:

> I'd be quite surprised if you find a switch that doesn't treat ff02::1 
> in the same way as IPv4 broadcast, by default.
>
> Saying that, I'd much prefer that IPv6 WoL had a known IPv6 multicast 
> address, as opposed to using ff02::1.

This is actually quite interesting. I read RFC 4291:

"All Nodes Addresses:    FF01:0:0:0:0:0:0:1
                               FF02:0:0:0:0:0:0:1

    The above multicast addresses identify the group of all IPv6 nodes,
    within scope 1 (interface-local) or 2 (link-local)."

So, one interpretation would be that if the device hasn't subscribed to 
the "all IPv6 nodes" multicast group, it's not an IPv6 node, and shouldn't 
receive the traffic.

Also, regarding the above, in order to keep being subscribed to a WoL 
multicast address group, wouldn't the NIC have to keep emitting REGISTER 
messages periodically? Is this something NICs do today, emitting packets 
while the CPU is in fairly deep sleep?

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se