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

[Fernando Gont <[e-mail]>]

Hello, Erik,

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

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

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.



>    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).

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: [e-mail]
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