Re: [v6ops] Fwd: New Version Notification for draft-collink-v6ops-ent64pd-01.txt

[Lorenzo Colitti <[e-mail]>]

On Thu, Dec 15, 2022 at 11:44 PM Gert Doering <[e-mail]> wrote:

> Something like a /96 per host - so "limitless amounts of host would
> fit into a single /64" would avoid that, and still fulfill the
> stated necessity of having many many many addresses per hosts.
>

The reason the draft mentions /64 is:

   - A /64 provides "infinite" addresses.
   - In practice, /64 is the only prefix length that supports SLAAC.
   - SLAAC is the only address assignment mechanism required to be
   supported by all hosts.

That means that a node that gets a /64 is guaranteed to be able to extend
the network indefinitely to all IPv6 nodes while maintaining end-to-end
connectivity to all of them. That's a major improvement over IPv4's current
capabilities. It's true that a /64 is relatively expensive in terms of
address space. That said, this proposal is targeted towards larger
networks. Fortunately, smaller networks tend to be less tightly managed,
and for many of those networks, directly using SLAAC is fine.

That said - based on past experience I fear that there is no single number
that will get consensus in this group. For example, I definitely wouldn't
want to *recommend* /96, because /96 would lose the above advantages. So,
how about we just state the facts? Something like:

=====
Delegating a /64 prefix to the client allows the client to provide
limitless addresses to IPv6 nodes connected to it (e.g., virtual machines,
tethered devices), because all IPv6 nodes are required to support SLAAC.
=====