Re: Adam Roach's Discuss on draft-ietf-6man-maxra-03: (with DISCUSS and COMMENT)

[Spencer Dawkins at IETF <[e-mail]>]

This isn't my area of expertise, my actual area, or my ballot thread, but
...

On Fri, Oct 27, 2017 at 11:41 AM, 神明達哉 <[e-mail]> wrote:

> At Thu, 26 Oct 2017 21:43:42 -0700,
> Ole Troan <[e-mail]> wrote:
>
> > It might be worth noting that if it is inclusive or exclusive has
> > absolutely zero consequence for the protocol.
>
> FWFIW, an implementation that I know of adopts the "inclusive" version
> of "between" (it doesn't support 6man-maxra so it still only conforms
> to RFC4861):
>
>     MAYHAVE(val, "rltime", rai->rai_maxinterval * 3);
>     if ((uint16_t)val && ((uint16_t)val < rai->rai_maxinterval ||
>         (uint16_t)val > MAXROUTERLIFETIME)) {
>         syslog(LOG_ERR,
>             "<%s> router lifetime (%" PRIu32 ") on %s is invalid "
>             "(must be 0 or between %d and %d)",
>             __func__, val, ifi->ifi_ifname, rai->rai_maxinterval,
>             MAXROUTERLIFETIME);
>         goto getconfig_free_rai;
>     }
> (https://github.com/freebsd/freebsd/blob/master/usr.sbin/rtadvd/config.c)
>
> But, more important, I agree with Bob and Ole in that "inclusive" vs
> "exclusive" shouldn't cause an interoperability problem since hosts
> are not supposed to reject an RA for a particular value of router
> lifetime:
>
>       Router Lifetime
>                      16-bit unsigned integer.  The lifetime associated
>                      with the default router in units of seconds.  The
>                      field can contain values up to 65535 and receivers
>                      should handle any value, while the sending rules in
>                      Section 6 limit the lifetime to 9000 seconds.  [...]
>
> If anything, if we now "clarify" it to mean "exclusive", at least one
> implementation will now become technically non-compliant.  So, while
> my primary suggestion is not to do anything about it, if we really
> need to say something, I'd suggest clarifying "whether this 'between'
> is inclusive or exclusive does not matter in terms interoperability
> and is left to implementations".
>

If the precise meaning of the boundaries set by a MUST requirement doesn't
actually matter, I'm not understanding why this is a MUST ...  Adam can
speak for himself, but that's what *I* would be confused about.

Spencer, who might or might not be Asking For A Friend


> --
> JINMEI, Tatuya
>
>