nanog mailing list archives

Re: Naive IPv6 (was AT&T UVERSE Native IPv6, a HOWTO)


From: Brian Dickson <brian.peter.dickson () gmail com>
Date: Wed, 4 Dec 2013 15:43:33 -0500

On Wed, Dec 4, 2013 at 3:09 PM, Owen DeLong <owen () delong com> wrote:


On Dec 4, 2013, at 10:21 , Brian Dickson <brian.peter.dickson () gmail com>
wrote:

Second of all, what would make much more sense in your scenario is
to aggregate at one or two of those levels. I'd expect probably the POP
and the Border device levels most likely, so what you're really looking
at is 5000*100 = 500,000 /48s per border. To make this even, we'll
round that up to 524,288 (2^19) and actually to make life easy, let's
take that to a nibble boundary (2^20) 1,048,576, which gives us a
/28 per Border Device.



Except that we have a hard limit of 1M total, which after a few 100K from
the
global routing tables (IPv4+IPv6), this 500,000 looks pretty dicey.



And root of the problem was brought into existence by the insistence that
every network (LAN) must be a /64.

Not really. The original plan was for everything to be 64 bits, so by
adding
another 64 bits and making every network a /64, we're actually better off
than we would have been if we'd just gone to 64 bit addresses in toto.

Thanks for playing.

Owen

Understand, I am not saying anyone got it wrong, but rather, that there is
a risk associated
with continuing forever to use a /64 fixed LAN size. Yes, we are better
than we
were, but the point I'm making is, if push comes to shove, that the /64 is
a small thing
to sacrifice (at very small incremental cost, SEND + AUTOCONF
modifications).

I can't believe I just called 2**64 small.

Brian


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