Partial vs Full tables

Fri Jun 5 17:20:00 UTC 2020

On Fri, Jun 5, 2020 at 9:49 AM Saku Ytti <saku at ytti.fi> wrote:
> The comparison isn't between full or default, the comparison is
> between static default or dynamic default. Of course with any default
> scenario there are more failure modes you cannot route around. But if
> you need default, you should not want to use dynamic default.

It's a little more nuanced than that. You probably don't want to
accept a default from your transit but you may want to pin defaults
(or a set of broad routes as I did) to "representative" routes you do
accept from your transit. By "pin" I mean tell BGP that 0.0.0.0/0 is
reachable by some address inside a representative route you've picked
that is NOT the next hop. That way the default goes away if your
transit loses the representative route and the default pinned to one
of your other transits takes over.

You can craft and tune an effective solution here, but there has to be
an awful lot of money at stake before the manpower is cheaper than
just buying a better router.

Regards,
Bill Herrin

-- 
William Herrin
bill at herrin.us
https://bill.herrin.us/