Re: [v6ops] New Version Notification for draft-yourtchenko-ra-dhcpv6-comparison-00.txt (fwd)

[Lorenzo Colitti <[e-mail]>]

On Thu, Dec 19, 2013 at 11:46 PM, Nick Hilliard <[e-mail]> wrote:

> > But what you propose is not simple. In fact, far from it. What you
> propose
> > requires a DHCPv6 server that's always up and perpetually maintains
> state,
> > and it requires that you run VRRP between the routers because DHCPv6.
>
> Probably I'm not alone in considering dhcp servers to be critical to a
> functional DHCP based network.  But as I said, I need DHCPv6 anyway
> and things will break if it's not available.
>

Fine, but please don't say it's simpler. It's not - it has way more moving
parts.


> > If you were designing a system from the ground up I'd wager you'd never
> > design it like that. So why do it like that, then?
>
> Can we stick to technical discussion?
>

We can, but it won't get us anywhere. You've said that you want to run your
network with DHCPv6 because RAs don't suit your requirements, and I'll say
that I want to run my network with RAs because DHCPv6 doesn't suit my
requirements. We will both have valid reasons, and probably we'll even
concede that in each other's networks the other's solution might be better.

But once we reach that point, we're still stuck. Because the only way
forward from there is to conclude that we need to define two completely
autonomous and competing systems to provision the same protocol on the same
host implementations, and choose one or the other depending on the
deployment scenario. This is a bad outcome, because hosts that want to work
everywhere (and what host doesn't?) need to implement both protocols. The
resulting complexity - which is more than 2x, because in addition to the
two protocols you have to define and implement rules to deal with their
interaction - pushes costs up for everyone, because everyone uses hosts,
including me and you.

That's why I say this is a dead horse - because there *is* no single
technically correct answer. The community has been through this exercise
many times. People who want to put routing in DHCP and people who don't
have had arguments in several working groups, each time with no conclusion,
resulting in a waste of everyone's time. Let's not repeat that, because it
isn't really in anybody's interest.

Instead, what we can do is document the semantic differences and properties
of the two protocols. After that, what we might be able to do is get
consensus on criteria for what should go into RA and into DHCPv6 in the
future. I think those are much mpre useful goals to pursue.