Subject: Re: [Gen-art] Gen-ART LC review of draft-ietf-v6ops-host-addr-availability-05

From: Jari Arkko <[email-masked]>
Date: Wed, 4 May 2016 17:07:08 -0400

I am going through the Gen-ART reviews related to documents on tomorrow’s IESG telechat agenda.

For this document, thanks a lot for your review, Roni.

Going to the comment and response from Lorenzo:

> The intent here is to say that while the DHCPv6 PD RFC uses the words "requesting router" to denote the DHCP client, is nothing in DHCPv6 PD itself that requires the PD client to be a router (where, in IPv6, the term "router" is defined in RFC2460).
> 
> So - even though the DHCPv6 PD RFC uses the term "requesting router", a host can use DHCPv6 PD to receive a prefix as well. The host can pick some addresses for that prefix for its own use, originate/terminate packets on those addresses, and not forward packets addressed to any of the other addresses in the prefix.

Lorenzo: Personally, I think it would perhaps useful to consider a slight reformulation of the text, given that for things like tethering or virtual machines, hosts essentially become routers.

Jari

---

From: Lorenzo Colitti <[email-masked]>
Date: Thu, 5 May 2016 12:29:12 +0900

On Thu, May 5, 2016 at 6:07 AM, Jari Arkko <[email-masked]> wrote:

> > So - even though the DHCPv6 PD RFC uses the term "requesting router", a
> host can use DHCPv6 PD to receive a prefix as well. The host can pick some
> addresses for that prefix for its own use, originate/terminate packets on
> those addresses, and not forward packets addressed to any of the other
> addresses in the prefix.
>
> Lorenzo: Personally, I think it would perhaps useful to consider a slight
> reformulation of the text, given that for things like tethering or virtual
> machines, hosts essentially become routers.

Personally I agree. I think hosts are routers that are currently not
forwarding packets

 However, this topic generated a lot of heat in the WG, with people arguing
vocally on both sides. So it was not easy to come up with this text.
There's also the fact that the IPv6 specification (RFC 2460 itself) defines
hosts and routers, and if we made a statement on the matter, we might have
had to formally update RFC 2460, which we did not want to attempt. (Bob, is
this something that could be re-examined in 2460bis? I think defining a
router as "a node that forwards packets" and a host as "a node that's not a
router" is a bit simplistic these days, particularly when a node decides to
enable forwarding between some set of its interfaces but not all.)

Going back to the text - Jari, do you have a suggestion on how to reword
this? The main reason that text is there is because a small number of WG
participants said, "we can't use DHCPv6 PD on hosts because DHCPv6 PD is
for routers and hosts aren't routers". We wanted to clarify that.

---

From: Vint Cerf <[email-masked]>
Date: Thu, 5 May 2016 05:09:43 -0400

when a host forwards packets it's a router. It is not a fixed state.

v

On Wed, May 4, 2016 at 11:29 PM, Lorenzo Colitti <[email-masked]> wrote:

>  However, this topic generated a lot of heat in the WG, with people
> arguing vocally on both sides. So it was not easy to come up with this
> text. There's also the fact that the IPv6 specification (RFC 2460 itself)
> defines hosts and routers, and if we made a statement on the matter, we
> might have had to formally update RFC 2460, which we did not want to
> attempt. (Bob, is this something that could be re-examined in 2460bis? I
> think defining a router as "a node that forwards packets" and a host as "a
> node that's not a router" is a bit simplistic these days, particularly when
> a node decides to enable forwarding between some set of its interfaces but
> not all.)
>

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