Why should an AP not be able to convert multicast->unicast. All it would ahve to do is IGMPv3 snooping to know the clients connected to it. And it does know the per-client bitrate, aka: how far or how close a client is.
I guess the one things that not possible is to send the smae multicast group/channel in both multicast and unicast from the same AP because that would potentially create persistent duplicates. On Tue, Apr 02, 2013 at 12:21:05AM +0200, Carsten Bormann wrote: > On Apr 1, 2013, at 22:56, Toerless Eckert <eck...@cisco.com> wrote: > > > It is clear that 802.11 is particularily challenged with native L2 > > multicast because > > they never defined a good resilience scheme as for unicast but so far not > > for multicast. > > Hopefully this will get fixed sometime. > > In a MIMO world, the performance gap between unicast and (indiscriminate) > multicast is likely to grow instead of shrink over time. > > Another little observation: > > Fixing this at the adaptation layer (i.e., where IP packets are mapped into > L2) is suboptimal, because you may not have visibility into the number of > member stations per AP. Once you have a few dozen on an AP, it may make > sense to switch back to multicast. For that AP! At the adaptation layer, > you only see the bridged 802 network, so you don't know how many stations > share an AP, and it is difficult to send multicast to one AP and > multi-unicast to another. It seems really hard to optimize this. Once you > have 802.11 (without any per-AP hacks) in your bridged 802 network, you > probably want to do 6085 globally. > > Pet peeve: We like to make things too "transparent", and then wonder how they > break horribly when you no longer can see what you are doing. > -> http://en.wikipedia.org/wiki/Leaky_abstraction > > Grüße, Carsten > -- --- Toerless Eckert, eck...@cisco.com Cisco NSSTG Systems & Technology Architecture SDN: Let me play with the network, mommy! -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
