Dual Homed BGP

Sun Feb 16 17:15:38 UTC 2020

Reading all the arguments one could generalize that choosing default/partial routes (instead of full feed) one is basically outsourcing all the control, convergence speed, security, etc.. to upstream providers.

adam

From: NANOG <nanog-bounces at nanog.org> On Behalf Of Amir Herzberg
Sent: Monday, January 27, 2020 1:49 PM
To: Job Snijders <job at instituut.net>
Cc: NANOG <nanog at nanog.org>
Subject: Re: Dual Homed BGP

Dear Job and NANOG,

Just wondering, wouldn't any of you guys consider using full tables in this case, for  the ability to detect and avoid prefix hijacks (using RPKI/ROV or other means)? 

Of course, I'm focused on security, and I know this is often not a high priority for a real network manager who has many other considerations; just want to know. Thanks. 

-- 
Amir 

On Fri, Jan 24, 2020 at 12:27 PM Job Snijders <job at instituut.net <mailto:job at instituut.net> > wrote:

Dear Brian,

On Fri, 24 Jan 2020 at 17:40, Brian <brian.bsi at gmail.com <mailto:brian.bsi at 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

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