Okay, In my use case it's just a default route being distributed by a router that has the full routing table to an access router in the same ASN. It's not being sent to other ASNs or anything of that sort. I was just curious as to why Cisco sets it to internal and Arista sets it to invalid. Thanks, -Drew -----Original Message----- From: NANOG <nanog-bounces+drew.weaver=thenap.com@nanog.org> On Behalf Of Olivier Benghozi Sent: Tuesday, July 7, 2020 12:47 PM To: nanog@nanog.org Subject: Re: rfc4271 ORIGIN/path of default route, should the value be 0 or 2? Debatable, certainly, as the Origin attribute should probably be considered as dead/obsolete and therefore it is probably a good practice to always set/reset it to internal. A number of networks already do this (including level3 by example). After all, the origin attribute was only designed to allow a «smooth» transition between EGP and BGP (that is, it was useful during a few years for a few networks several decades ago).
Le 7 juil. 2020 à 15:47, Saku Ytti <saku@ytti.fi> a écrit :
Debatable, but: Internal is more accurate if you redistribute default from routing protocol, such as static. Unknown is more accurate if you just generate it in BGP, without having it.
Functional difference is best-path selection algorithm. Origin can be used to bypass hot-potato policies of peers, by forcing them to carry packets longer inside their network. If your policy is hot-potato, then you should reset Origin on received external routes.