Re: [Last-Call] Last Call: <draft-ietf-6man-ra-pref64-07.txt> (Discovering PREF64 in Router Advertisements) to Proposed Standard - PLC consistency

[Jen Linkova <[e-mail]>]

On Wed, Nov 6, 2019 at 6:19 PM Alexandre Petrescu
<[e-mail]> wrote:
> draft says:
> > Scaled Lifetime field SHOULD by default be set to the lesser of 3 x
> > MaxRtrAdvInterval divided by 8, or 8191
>
> If MaxRtrAdvInterval is 1 (RFC6275 'Mobile IPv6', radvd.conf) then the
> division wont work, so the 'lesser' wouldnt be computed.

We can add the following text: 'if 3 x MaxRtrAdvInterval  is less than
8 then the Scaled Lifetime field SHOULD by default be set to 1',

On the side note: it looks to me that RFC6275 contradicts 'MUST' in RFC4861:

RFC6275: "Routers supporting mobility SHOULD be able to be configured
with a smaller MinRtrAdvInterval value and MaxRtrAdvInterval value....
MinRtrAdvInterval 0.03 seconds, MaxRtrAdvInterval 0.07 seconds"
while RFC4861  states that  "MaxRtrAdvInterval ..MUST be no less than
4 seconds" and "MinRtrAdvInterval...MUST MUST be no less than 3
seconds").

At the same time RFC6275 is not formally updates RFC4861..

> Then, by 'lifetime', in the cited text below and throughout the
> document, one means the 'Scaled Lifetime' of this option, right?

It actually does not matter, as zero Scaled lifetime means zero
lifetime, and non-zero Scaled Lifetime means non-zero actual lifetime.

> > Routers SHOULD check and compare the following information:
> >
> > o  set of PREF64 with non-zero lifetime;
> >
> > o  set of PREF64 with zero lifetime.
>
> Finally, for my curiosity, I wonder what kind of algorithm for checking
> is consideredin each case.  Is it a precise checking, or more relaxed?
> For example, how does it compare a /96 to a /64 (with a precise checking
> they cant match, but with a longest match checking they could); would an
> absolute or a partial majority in the set be needed to win the check, etc.

2001:db8::/96 and 2001:db8::/64 are two different prefixes IMHO.
'Longest prefix match' etc applies when you are finding a prefix a
particular IP address belongs to, not when you compare two prefixes.
Also please note that it's just a check for configuration consistency
within a LAN/PvD.

> >
> > Abstract
> >
> >
> > This document specifies a Neighbor Discovery option to be used in
> > Router Advertisements to communicate NAT64 prefixes to hosts.
> >
> >
> >
> >
> > The file can be obtained via
> > https://datatracker.ietf.org/doc/draft-ietf-6man-ra-pref64/
> >
> > IESG discussion can be tracked via
> > https://datatracker.ietf.org/doc/draft-ietf-6man-ra-pref64/ballot/
> >
> >
> > No IPR declarations have been submitted directly on this I-D.
> >
> >
> >
> >
> > _______________________________________________ IETF-Announce mailing
> > list [e-mail]
> > https://www.ietf.org/mailman/listinfo/ietf-announce
> >
>
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-- 
SY, Jen Linkova aka Furry