nanog mailing list archives

Re: World IPv6 Only Day.


From: TJ <trejrco () gmail com>
Date: Thu, 9 Jun 2011 14:56:45 -0400

On Thu, Jun 9, 2011 at 13:34, Ray Soucy <rps () maine edu> wrote:

Cisco has had MLD snooping support for some time.  But they seem to
have broken it in a recent release, so it drops ND traffic and breaks
IPv6; been after them to fix it, but doesn't look like it's been
resolved yet.

But you're correct that without MLD snooping IPv6 ND traffic is on par
with IPv4 broadcast traffic and not a major problem.  <snip>


While I certainly agree it is not a major problem, it should be _even less_
of a problem than ARP.  Yes, the non-MLD-snooping switch forwards all
multicast to every port - but the other end of those cables (the nodes
plugged in to the switch) don't need to process the frame at all - not
listening for that MAC.  Compared to ARP, where the frame is picked up and
handed to layer3/IPv4 before being discarded.


/TJ


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