Re: [v6ops] Interesting problems with using IPv6

Brian E Carpenter <brian.e.carpenter@gmail.com> Mon, 15 September 2014 20:20 UTC

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Date: Tue, 16 Sep 2014 08:20:54 +1200
From: Brian E Carpenter <brian.e.carpenter@gmail.com>
Organization: University of Auckland
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To: Mikael Abrahamsson <swmike@swm.pp.se>
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Cc: IPv6 Operations <v6ops@ietf.org>
Subject: Re: [v6ops] Interesting problems with using IPv6
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On 15/09/2014 17:04, Mikael Abrahamsson wrote:
> On Mon, 15 Sep 2014, Brian E Carpenter wrote:
> 
>> was MLD snooping (i.e. a layer violation by L2 switches). Even so,
> 
> This is the first time I have seen anyone calling MLD/IGMP snooping a
> "layer violation by L2 switches" (I'm interpreting this as you thinking
> it's negative, do tell if this is not the case).

Yes, layer violations have this nasty habit of coming back and
biting you, and this is an example.

> How else is L2 equipment going to make intelligent decisions about
> multicast forwarding within an L2?

They're not. That's why DEC Gigaswitches had ARP throttling, for example,
to control broadcast storms. It's unavoidable if you build big L2
networks. I learnt not to do that.

    Brian