v6 subnet size for DSL & leased line customers

Deepak Jain deepak at ai.net
Mon Dec 24 19:09:42 UTC 2007

Christopher Morrow wrote:
> On Dec 22, 2007 12:23 PM, Ross Vandegrift <ross at 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 :(

I think this is the point I was trying to make. Just because we have "so 
many bits" now... why does the equipment/software need to get "stupider" 
again? Are we going to have an IPv6 CIDR initiative again (15 years from 
now) to recover all of that wasted space from "early" allocations)..

Merry Christmas, and junk.


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