Re: [Int-area] Alissa Cooper's No Objection on draft-ietf-intarea-frag-fragile-16: (with COMMENT)

[Tom Herbert <[e-mail]>]

On Tue, Sep 3, 2019 at 1:49 PM Fernando Gont <[e-mail]> wrote:
>
> On 3/9/19 23:33, Tom Herbert wrote:
> > Bob,
> >
> > I agree with Fred. Note, the very first line of the introduction:
> >
> > "Operational experience [Kent] [Huston] [RFC7872] reveals that IP
> > fragmentation introduces fragility to Internet communication".
> >
> > This attempts to frame fragmentation as being generally fragile with
> > supporting references. However, there was much discussion on the list
> > about operational experience that demonstrates fragmentation is not
> > fragile.
>
> Discussion is not measurements. Do you have measurements that suggest
> otherwise?
>
> We did separate measurements, with different methodologies, and they
> suggest the same thing. You can discuss as much as you want. But that
> will not make fragmentation work.
>
>
>
> > In particular, we know that fragmentation with tunnels is
> > productively deployed and has been for quite some time. So that is the
> > counter argument to the general statement that fragmentation is
> > fragile. With the text about tunneling included in the introduction I
> > believe that was sufficient balance of the arguments, but without the
> > text the reader could be led to believe that fragmentation is fragile
> > for everyone all the time which is simply not true and would be
> > misleading.
>
> "fragile" means that it fails in an uncceptably large number of cases.
> ~30 failure rate is not acceptable. ~20% isn't, either.
>
Okay, so then the definition of a fragile protocol is one that has a
failure rate greater than 20%? If so, then that should really be
stated in the draft. But, then I'd point out that per
https://www.google.com/intl/en/ipv6/statistics.html, IPv6 is only
supported by 30% of the Internet at best, so it fails 70% of the time.
So by that same definition, isn't IPv6 fragile?

Tom

> >
>
>
>
> > But the "problem" of fragmentation is in intermediate devices that
> > don't properly handle it as the draft highlights. So it seems like
> > part of addressing the problem should also be to fix the problem! That
> > is implementations should be fixed to deal with fragmentation.
>
> The same logic would solve the problem of widespread famine, and others.
> I don't think that logic has solved any real problems in the real world.
>
> --
> Fernando Gont
> SI6 Networks
> e-mail: [e-mail]
> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
>
>
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