nanog mailing list archives

Re: v6 subnet size for DSL & leased line customers


From: "Christopher Morrow" <morrowc.lists () gmail com>
Date: Sat, 22 Dec 2007 12:53:52 -0800


On Dec 22, 2007 12:23 PM, Ross Vandegrift <ross () kallisti us> wrote:

On Fri, Dec 21, 2007 at 01:33:15PM -0500, Deepak Jain wrote:
For example... Within one's own network (or subnet if you will) we can
absorb all the concepts of V4 today and have lots of space available.
For example... for the DMZ of a business... Why not give them 6 bits
(/122?) are we anticipating topology differences UPSTREAM from the
customers that can take advantage of subnet differences between /64 and
/56 ?

I am confused on this point as well.  IPv6 documents seem to assume
that because auto-discovery on a LAN uses a /64, you always have to
use a /64 global-scope subnet.  I don't see any technical issues that
require this though.  ICMPv6 is capable of passing info on prefixes of
any length -  prefix length is a plain old 8bit field.


Uhm, so sure the spec might be able to do something different than /64
but most equipment I've used only does auto-conf if the prefix is a
/64 :( Somewhere along the path to ipng we got reverted to classful
addressing again :(

-Chris


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