Re: Stateful SLAAC (draft-ietf-v6ops-unique-ipv6-prefix-per-host)

Lorenzo Colitti <lorenzo@google.com> Fri, 10 November 2017 04:45 UTC

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From: Lorenzo Colitti <lorenzo@google.com>
Date: Fri, 10 Nov 2017 13:45:14 +0900
Message-ID: <CAKD1Yr00v6zhygr2W=+jz9N=cED8pmqPfGSOHzhwpr6aNdig7Q@mail.gmail.com>
Subject: Re: Stateful SLAAC (draft-ietf-v6ops-unique-ipv6-prefix-per-host)
To: Fred Baker <fredbaker.ietf@gmail.com>
Cc: Fernando Gont <fgont@si6networks.com>, IPv6 Operations <v6ops@ietf.org>, "6man@ietf.org" <6man@ietf.org>, "6man-ads@tools.ietf.org" <6man-ads@ietf.org>, "v6ops-ads@ietf.org" <v6ops-ads@ietf.org>, draft-ietf-v6ops-unique-ipv6-prefix-per-host@tools.ietf.org
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On Fri, Nov 10, 2017 at 10:18 AM, Fred Baker <fredbaker.ietf@gmail.com>;
wrote:

> > I don't see how this is a protocol change. Sending RAs unicast is
> already allowed by RFC 4861, so this is just an operational practice.
>
> I understand the concern to be sending to a multicast address at the
> network layer and a unicast address at the link layer. If 4861 allows the
> RA to be sent unicast, it is probably unicast at both layers. I suspect
> that if we change to doing what 4861 describes we'll be fine.
>

That's already allowed by RFC 6085, which states:

   "Transmission of IPv6 Packets over Ethernet Networks" ([RFC2464],
   Section 7) specifies how an IPv6 packet with a multicast destination
   address is mapped into an Ethernet link-layer address.  This document
   extends this mapping to explicitly allow for a mapping of an IPv6
   packet with a multicast destination address into an Ethernet link-
   layer unicast address, when it is clear that only one address is
   relevant.