Re: Dual Homed BGP

[Job Snijders <job () instituut net>]

Dear Brian,

On Fri, 24 Jan 2020 at 17:40, Brian <brian.bsi () gmail com> wrote:

> Hello all. I am having a hard time trying to articulate why a Dual Home
> ISP should have full tables. My understanding has always been that full
> tables when dual homed allow much more control. Especially in helping to
> prevent Async routes.

The advantage of receiving full routing tables from both providers is that
in cases where one of the two providers is not yet fully converged, your
routers will use the other provider for those missing destinations. This
may happen during maintenance or router boot-up in your upstream’s network.

Another advantage of receiving full routes is that you can manipulate
LOCAL_PREF per destination, or compose routing policy based on per-route
attributes such as BGP communities your upstreams set. It can happen that a
provider is great for 99% of destinations, except a few - without full
tables such granular traffic-engineering can be cumbersome.

Virtually all internet routing is asymmetric, I wouldn’t consider that an
issue.

Am I crazy?
>

I dropped out of university, never completed my psychology studies, I fear
I am unqualified to answer this question. ;-)

Kind regards,

Job