[171460] in North American Network Operators' Group
Re: The Cidr Report
daemon@ATHENA.MIT.EDU (Fred Baker (fred))
Wed Apr 30 17:36:48 2014
X-Original-To: nanog@nanog.org
From: "Fred Baker (fred)" <fred@cisco.com>
To: Deepak Jain <deepak@ai.net>
Date: Wed, 30 Apr 2014 21:32:27 +0000
In-Reply-To: <aa49981d2cf64b6a8b2d3c245e9cb0f5@AINET-EX13-S02.ainet.local>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
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On Apr 26, 2014, at 12:19 PM, Deepak Jain <deepak@ai.net> wrote:
> Does anyone have doomsday plots of IPv6 prefixes? We are already at =
something like 20,000 prefixes there, and a surprising number of =
deaggregates (like /64s) in the global table. IIRC, a bunch of platforms =
will fall over at 128K/256K IPv6 prefixes (but sooner, really, because =
of IPv4 dual stack).
A /64 deaggregte only makes it through because folks let it; there=92s =
something to be said for filters. That said, one might generally expect =
every AS (there are about 60K or them, I gather) to have one prefix, and =
if it deaggregates, it might be reasonable to expect it to multiply by =
four. RIR online records suggest that someone that asks for additional =
addresses beyond their /32 is told to shorten the existing prefix, not =
allocated a new one - the same prefix becomes a /31 or whatever. The =
reason we have 500K+ IPv4 prefixes is because we hand them out in =
dribbles, and there is no correlation between the one you received last =
week and the one you receive today.
Geoff=92s slides are interesting in part because of their observations =
regarding deaggregates. If 1% of of all AS=92s advertise over half of =
the deaggregates, that seems like a problem their neighbors can help =
with, and if not them, the neighbors' neighbors. It=92s hard to imagine =
that a single Ethernet (a single /64) is so critical that the entire =
world needs a distinct route to it.
In any event, I would not approach this as a statistical issue, and say =
=93well, IPv4 grew in a certain way, and IPv6 will do the same=94. It =
can. But we have had the opportunity to think ahead and plan for the =
growth, and the RIR communities have been planning. It seems likely =
that, with a little care, IPv6 should do quite a bit better.
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