Re: [Rift] IPv4 vs IPv6

[Mikael Abrahamsson <[e-mail]>]

On Thu, 18 Jul 2019, Tony Przygienda wrote:

> Please dig out the archive where that discussion was brought up by Alvaro
> and follow up there if you still have doubts.

Since I cannot reply to that thread (I just subscribed to the list so I 
don't have an original email to reply to), that's hard.

Anyhow, I think the IPv4 MUST should be removed. It's 2019 now, we should 
not mandate IPv4 support in anything.

> not to the requirements _of devices runing RIFT_:  we cannot mandate 
> that everyone in reality will run IPv6 forwarding on the fabric so the 
> reality is that every silicon does IPv4 today and some does IPv6. And

This fact doesn't warrant making IPv4 a MUST. Think 5-10 years down the 
line, there might be IPv6 only silicon and control plane. Why should 
future implementors be required to implement IPv4 if they do not want to?

> then IPv4 over IPv6 is reality while IPv6 over IPv4 is not (since IPv6 
> does ND anyway so why would you).  So it is very good for v6 here to 
> basically make it an implicit transport for v4 (by saying running v6 
> does _automatically_ give you v4 forwarding) while making sure that v4 
> being-de-facto-what-e'one-can-do is the lowest common denominator of the 
> router's running RIFT. RIFT being only usable if a router/switch can do 
> IPv6 is simply not a practical proposition AFAIS.  We could arguably 
> split it into a "RIFT router/switch requirements document" but that 
> seems just paper bloat ...

I am not proposing making IPv6 a MUST, but I am against making IPv4 a 
MUST. Better to be silent on the matter in that case so future 
implementors can decide for themselves.

I just made me cringe when I read the IPv4 MUST in the document.

-- 
Mikael Abrahamsson    email: [e-mail]