nanog mailing list archives

Re: IPv6 and multicast listener discovery


From: Baldur Norddahl <baldur.norddahl () gmail com>
Date: Sat, 5 Jun 2021 00:23:19 +0200

If you enable MLD snooping on your switches, the switch will block
multicast going out irrelevant ports. The idea is to reduce broadcast in a
broadcast domain.

On Fri, Jun 4, 2021 at 11:03 PM William Herrin <bill () herrin us> wrote:

Howdy,

Question for those more versed in IPv6 than I: Is there any harm from
dropping ICMPv6 multicast listener discovery reports in a network
which does NOT use any multicast routing (i.e. only uses multicast
which stays within the local link). I see a LOT of idle node chatter
in the form of these reports which, of course, flood every station
since they are themselves multicast. As far as I can tell they are
used only to tell a multicast router whether to repeat a particular
set of multicast packets to the instant link. Which in my network is
-never- because there are no routed multicast packets to be repeated.

Regards,
Bill Herrin

--
William Herrin
bill () herrin us
https://bill.herrin.us/


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