Re: 6man w.g. last call for <draft-ietf-6man-grand>

[Mark Smith <[e-mail]>]

Hi,

Unfortunately I don't support advancement right now, as I've had some
further fairly significant suggestions for it which I've been
struggling to finding time to provide. Apologies for the delay,
started a new job.

In summary, and I'll provide more details and text over the weekend:

- I've changed my mind on the idea of an optimisation of not
performing this for link-local addresses i.e. only performing it for
off-link addresses, for two reasons:

  -  IPv6 routers may need to send ICMPv6 messages to hosts, and can
use and will prefer link-local addresses for that if possible.

  - IPv6 routers can forward packets with link-local addresses as long
as it is back on to the same link, per RFC4007 (I'm not sure of the
use case, perhaps NBMA links? draft-smith-6man-link-locals-off-link
would allow it on multiaccess broadcast links).

  Both of these cases means that using GRAND to proactively load a
router's ND cache with entries for a hosts' link-local address(s)
would be beneficial, and it would be a simpler mechanism to do GRAND
for all types of new addresses regardless.


- Regarding the idea of using link-lay unicasts to send these
messages, another way to identify routers to send them to would be to
use the Router flag that is supplied in ND NAs. Needs a bit more
thought, however this may overcome the limitation of hosts not being
required to keep all routers in their default router list. Possibly
hosts will remember these ND NA cache entries, for the purposes of
NUD, even though they might not remember the corresponding RA router
entries on their Default Router list.

(Actually, thinking about it more right now, RA announced routers
don't have to be default routers i.e. Router Lifetime == 0, they can
supply more specific routes to hosts via the RFC4191 Route Information
Option, not sure if it is mandatory for hosts to remember all RIOs and
their announcing, RL==0 routers. (Senario: All routers' RAs RL=0, RAs
however have RIOs, hosts ignore RIOs so can't reach anything if RIOs
are optional to remember))


Apologies again for the delay.

Regards,
Mark.




On Thu, 16 Jul 2020 at 03:17, Bob Hinden <[e-mail]> wrote:
>
> Hello,
>
> This message starts a new two week 6MAN Working Group Last Call on advancing:
>
>         Title:    Gratuitous Neighbor Discovery: Creating Neighbor Cache Entries on First-
>                   Hop Routers
>         Author:   Jen Linkova
>         Filename: draft-ietf-6man-grand-00
>         Pages:    11
>         Date:     March 9, 2020
>
>        https://tools.ietf.org/html/draft-ietf-6man-grand
>
> as a Proposed Standard.
>
> Substantive comments and statements of support for publishing this document should be directed to the mailing list.  Editorial suggestions can be sent to the author.  This last call will
> end on 29 July 2020.
>
> Thanks,
> Bob & Ole
>
>
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