Re: [v6ops] Interesting problems with using IPv6
Erik Nordmark <nordmark@acm.org> Mon, 15 September 2014 22:09 UTC
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Date: Mon, 15 Sep 2014 15:08:53 -0700
From: Erik Nordmark <nordmark@acm.org>
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To: Brian E Carpenter <brian.e.carpenter@gmail.com>, 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 9/15/14, 1:20 PM, Brian E Carpenter wrote: > 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. Brian, I don't think we have sufficient data on the contributions of the different factors that resulted in triggering the implementation problems in this case. The overloading of IGMP for to both feed L3 multicast routing information into routers and to feed L2 multicast information into IGMP snooping switches (which was faithfully carries forward into MLD) certainly is part of the picture. That results in the routers seeing MLD reports for link-local groups, which the routers do not care about. But even if we had a non-overloaded approach (with L2 multicast membership being propagated by IEEE *Multiple Registration Protocol* (*MRP*) instead of IGMP/MLD snooping), the L2 switches would still be overloaded with so many temporary addresses and associated solicited-node multicast addresses. Of course, I've never seen a host which implements MRP, but that is separate from the implied architectural question about which part of the blame should be placed on overloading (or layer violations if you prefer that term) in this case. Regards, Erik > >> 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 > > _______________________________________________ > v6ops mailing list > v6ops@ietf.org > https://www.ietf.org/mailman/listinfo/v6ops >
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Mark ZZZ Smith
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Fernando Gont
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Philip Homburg
- Re: [v6ops] Interesting problems with using IPv6 Nick Hilliard
- Re: [v6ops] Interesting problems with using IPv6 Tore Anderson
- Re: [v6ops] Interesting problems with using IPv6 Nick Hilliard
- Re: [v6ops] Interesting problems with using IPv6 Lorenzo Colitti
- Re: [v6ops] Interesting problems with using IPv6 Hemant Singh (shemant)
- Re: [v6ops] Interesting problems with using IPv6 Chuck Anderson
- Re: [v6ops] Interesting problems with using IPv6 Fernando Gont
- Re: [v6ops] Interesting problems with using IPv6 Hemant Singh (shemant)
- Re: [v6ops] Interesting problems with using IPv6 Andrew 👽 Yourtchenko
- Re: [v6ops] Interesting problems with using IPv6 Hemant Singh (shemant)
- Re: [v6ops] Interesting problems with using IPv6 Andrew 👽 Yourtchenko
- Re: [v6ops] Interesting problems with using IPv6 Brian Haberman
- Re: [v6ops] Interesting problems with using IPv6 神明達哉
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Fernando Gont
- Re: [v6ops] Interesting problems with using IPv6 Fernando Gont
- Re: [v6ops] Interesting problems with using IPv6 Fernando Gont
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Fernando Gont
- Re: [v6ops] Interesting problems with using IPv6 Andrew 👽 Yourtchenko
- Re: [v6ops] Interesting problems with using IPv6 Brian Haberman
- Re: [v6ops] Interesting problems with using IPv6 Brian Haberman
- Re: [v6ops] Interesting problems with using IPv6 Brian Haberman
- Re: [v6ops] Interesting problems with using IPv6 Andrew 👽 Yourtchenko
- Re: [v6ops] Interesting problems with using IPv6 Fernando Gont
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 joel jaeggli
- Re: [v6ops] Interesting problems with using IPv6 Brian Haberman
- Re: [v6ops] Interesting problems with using IPv6 Ray Hunter
- Re: [v6ops] Interesting problems with using IPv6 Erik Nordmark
- Re: [v6ops] Interesting problems with using IPv6 Owen DeLong
- Re: [v6ops] Interesting problems with using IPv6 Chuck Anderson
- Re: [v6ops] Interesting problems with using IPv6 Fernando Gont
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Owen DeLong
- Re: [v6ops] Interesting problems with using IPv6 Owen DeLong
- Re: [v6ops] Interesting problems with using IPv6 Sander Steffann
- Re: [v6ops] Interesting problems with using IPv6 Bernie Volz (volz)
- Re: [v6ops] Interesting problems with using IPv6 Sander Steffann
- Re: [v6ops] Interesting problems with using IPv6 Owen DeLong
- Re: [v6ops] Interesting problems with using IPv6 Owen DeLong
- Re: [v6ops] Interesting problems with using IPv6 Mark ZZZ Smith
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Mikael Abrahamsson
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Erik Nordmark
- Re: [v6ops] Interesting problems with using IPv6 Nick Hilliard
- Re: [v6ops] Interesting problems with using IPv6 Brian E Carpenter
- Re: [v6ops] Interesting problems with using IPv6 Mikael Abrahamsson