[Bloat] tiny monsters: multicast packets

[Juliusz Chroboczek]

> And the irony is that the lower speed is specifically chosen for
> multicast in order to make sure all clients in range can hear them
> reliably.

It was my understanding that it was done for compatibility with older
devices, since 2 Mbit/s is the fastest rate supported by pre-B
spread-spectrum hardware.

> 2) Unicast the packet to each attached host in turn,

Both DVMR and the multicast part of BATMAN-adv do that for router-router
links.

A better link-layer solution, IMHO, would be to multicast (with ARQ) the
packet at a reasonably high rate (say, the median of the STAs subscribed
to the multicast group), and then unicast it to all STAs that failed to
return an ACK.  Interestingly, if the new multicast frame format is
incompatible with the normal 802.11 format, then this scheme is
compatible with legacy devices, which won't ever see the multicast frame
and hence won't return an ACK.

> So the workaround is to isolate the broadcast domains of wired
> networks and wireless networks by making the home router into...
> a router.  Wireless on one subnet, wired on another, and so ARP
> between the two turns into ARP to the router alone - much more
> scalable.

OpenWRT is your friend.

-- Juliusz