Subject: [v6ops] Erik Kline's Yes on draft-ietf-v6ops-cpe-slaac-renum-07: (with COMMENT)

From: Erik Kline via Datatracker <[email-masked]>
Date: Wed, 24 Feb 2021 22:21:38 -0800

Erik Kline has entered the following ballot position for
draft-ietf-v6ops-cpe-slaac-renum-07: Yes

When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)

Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
for more information about IESG DISCUSS and COMMENT positions.

The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-v6ops-cpe-slaac-renum/

----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

[[ comments ]]

[ section 3.4 ]

* At the end of the 2nd paragraph and the 2nd NOTES paragraph, I think it
  could be made clearer that this recommendation especially applies to ND
  Options that contain address or prefix information from within a prefix
  learned on the WAN side.

  These timers seem fine in general as well, but I think as written it's
  a blanket recommendation without explicitly saying why these options
  need updating, i.e. if someone asks what does "if and where applicable"
  actually mean -- it means ND options with address/prefix information
  taken from a delegated prefix whose lifetime has been reduced
  (possibly to zero, possibly progressively shorter values trending to zero).

---

From: Fernando Gont <[email-masked]>
Date: Thu, 25 Feb 2021 04:18:48 -0300

Hello, Erik,

Thanks a lot for your comments! In-line....

On 25/2/21 03:21, Erik Kline via Datatracker wrote:
[....]

Are you referring that of "the lifetimes not spanning past the remaining 
lifetime", or to the recommendation to set the PIO lifetimes to 
(ND_VALID_LIMIT, ND_PREFERRED_LIMIT).

If the former, I definitely agree. If the latter, I'd probably argue 
that when it comes to PIOs the advice is also valid even if the prefix 
is locally generated. -- e.g., consider the case where a CE Router is 
simply replaced by another one. If the (VL, PL) was (1 week, 1 month) 
you'd have them around for quite a while (same for e.g. RDNSS options). 
-- that said, I wouldn't mind clarifying that this only applies to 
sub-prefixes of prefixes learned from the WAN-side if you think that's 
warranted.

>    (possibly to zero, possibly progressively shorter values trending to zero).

FWIW, what we *meant* with "if and where applicable" was essentially 
"[any future] Neighbor Discovery options that depend in any way on 
changes in the prefix employed for address configuration on the LAN-side"

Just let us know how we should clarify the above.

Thanks a lot!

Regards,
-- 
Fernando Gont
SI6 Networks
e-mail: [email-masked]
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492