Re: [Lsr] Thoughts about PUAs - are we not over-engineering?

All,

> What is wrong with simply not doing summaries

What's wrong is that you are reaching the scaling issue much sooner than
when you inject summaries.

Note that the number of those host routes is flooded irrespective of the
actual need everywhere based on the sick assumption that perhaps they may
be needed there. There is no today to the best of my knowledge controlled
leaking to only subset to what is needed.

But this is not the main worry. Main worry is that in redundant networks
you are seeing many copies of the very same route being flooded all over
the place. So in a not so big 1000 node network the number of host routes
may exceed 8000 easily.

Sure when things are stable all is cool. But we should prepare for the
worst, not the best. In fact, the ability to encapsulate to an aggregate
switch IP (GRE or UDP) or nowadays SRv6 has been one of the strongest
advantages.

So as started before the problem does exist. Neither PULSE nor PUE solve it
which are both limited to PE failures detection which is not enough (maybe
even not worth). But PE-CE failures need to be signalled in the case of
injecting summaries. Maybe as I said in previous msg just BGP withdrawal is
fine. If not we should seek a solution which addresses the real problem,
not an infrequent one.

Best,
R.

On Tue, Jun 14, 2022 at 2:51 PM Christian Hopps <chopps@chopps.org> wrote:

>
>
> > On Jun 14, 2022, at 04:59, Van De Velde, Gunter (Nokia - BE/Antwerp) <
> gunter.van_de_velde@nokia.com> wrote:
> >
> > What is wrong with simply not doing summaries and forget about these
> PUAs to pinch holes in the summary prefixes? this worked very well during
> last two decennia. Are we not over-engineering with PUAs?
>
> 100% yes, IMO.
>
> Thanks,
> Chris.
> [as wg-member]
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