Re: draft-bourbaki-6man-classless-ipv6-00

[Lorenzo Colitti <[e-mail]>]

On Wed, Jun 14, 2017 at 6:59 PM, Peter Hessler <[e-mail]> wrote:

> I'm already running non-/64 subnets on my personal networks.  I'm also
> running non-/64 subnets on my $work networks.
>
> mandating /64 subnets in the _architectural specification_ is a bug,
> period.
>
> IPv4 got rid of classful subnets in 1993, IPv6 can join the last century
> as well.
>

Brian (and everyone on this thread, really): QED.

Peter, thanks for writing this email so clearly. I think we now have a
clear example of what some operators will feel encouraged to do if we
change "is /64" to "should be /64". With the the current state of affairs,
such networks happen to work but are not guaranteed to interoperate, and
host implementations are not required to work on them. If we change the
standards to admit that subnets may be non-64 bits, there will be pressure
on implementations to conform.

Even if this sort of opinion were a minority opinion among network
operators, it is the nature of networking software development that host
implementations adapt to the lowest common denominator. Let's not do that
here. There is no technical reason to do so.

This is exactly the sort of scarcity thinking that the 64-bit boundary is
intended to avoid. Let's ensure that such limitations - which as Peter
says, belong to the last century - stay in the last century and do not
enter this one.