nanog mailing list archives

Re: 10GBASE-T Switches


From: Karl Auer <kauer () biplane com au>
Date: Fri, 11 Feb 2011 06:52:07 +1100

On Thu, 2011-02-10 at 20:33 +0100, Daniel Roesen wrote:
Be aware, that IGMP snooping breaks some(!) IPv6 multicast (e.g.
DHCPv6). Affects whole EX-series and current plan is to fix it sometime
end of year (Q4 release). If you use IPv4 multicast and need IGMP
snooping to prevent flooding and plan to use e.g. stateful DHCPv6, that
might be a showstopper for now and the VLANs where IGMP snooping is
enabled.

Not disagreeing, I've never met this device, just curious about the
problem and wondering if it is a generic class of problem.

Is this device supposed to be IPv6-capable? If so, IGMP snooping and MLD
snooping should be able to coexist, I'd have thought. In fact, it will
be a major blow for the future of dual-stacking if they can't.

So is the problem of which you speak just a bug, or is it an artifact of
the switch not being IPv6 capable and so limiting broadcasts at the
ethernet level to IGMP-discovered listeners only, ignoring IPv6
multicast listeners? Or something :-)

Also. why does it only affect DHCPv6? Or was that just an example of a
service that would be affected by the problem?

Regards, K.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer () biplane com au)                   +61-2-64957160 (h)
http://www.biplane.com.au/kauer/                   +61-428-957160 (mob)

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