Re: [Rift] Ipv4 and ipv6 cooperating in rift

[Antoni Przygienda <[e-mail]>]

Alvaro, understood and I know you're here to guide with a loving but firm hand ;-) I tried to elucidate ;-) that AFAIS we follow the charter fine in this case but of course I'm waiting for others to chime in if they see things differently ...

thanks

--- tony

________________________________
From: Alvaro Retana <[e-mail]>
Sent: Thursday, July 11, 2019 11:42 AM
To: Antoni Przygienda; [e-mail]
Cc: Jeffrey (Zhaohui) Zhang; [e-mail]; [e-mail]
Subject: Re: [Rift] Ipv4 and ipv6 cooperating in rift

Tony:

Hi!

As I said before, I may be jumping in without proper context…. I just want to make sure that we don’t end up with discussions about the charter or how much it may or may not reflect reality later in the process.  If a change needs to be made, better sooner than later…if no change is needed, then we’re good. :-)

Alvaro.


On July 11, 2019 at 11:49:12 AM, Antoni Przygienda ([e-mail]<mailto:[e-mail]>) wrote:

Alvaro, protocol specification requirements and router running the protocol requirements are AFAIS not the same thing. And the distinction is meaningful here.

So, the protocol DOES support IPv6 and it DOES suppoort IPv4 so it does fulfill the charter you refer to perfectly.

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 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 ...

So I think we are meeting the charter mandating protocol specification perfectly while @ the same the spec is aligning with reality of v4ov6 forwarding without v4 addresses. We could just as well remove the sentence and everything would work except we'd end up in lots of discussions/possibly non-interoperable implementations in regards to v4 forwarding when no v4 addresses are present and people considering things undeployable until all the silicon in the world does v6 and everyone runs v6 by default everywhere. Which may happen but not in a foreseable future I can discern ...

I hope I do make sense ...

--- tony


________________________________
From: Alvaro Retana <[e-mail]<mailto:[e-mail]>>
Sent: Thursday, July 11, 2019 8:15 AM
To: Antoni Przygienda; [e-mail]<mailto:[e-mail]>
Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; Jeffrey (Zhaohui) Zhang
Subject: Re: [Rift] Ipv4 and ipv6 cooperating in rift

On July 10, 2019 at 11:05:40 AM, Antoni Przygienda (prz=[e-mail]<mailto:prz=[e-mail]>) wrote:

Hi!

I might be jumping in without proper context, but this text caught my attention...

b) If you want the "laziest" possible implementation then in fact yes, you can fall back on

"

All RIFT routers MUST support IPv4 forwarding and MAY support IPv6
   forwarding.  A three way adjacency over IPv6 addresses implies
   support for IPv4 forwarding.

"

…because the WG Charter says that "The protocol must support IPv6 and should also support IPv4.”   So the text above contradicts the Charter.

Alvaro.