RE: how about a well-known DOWNGRADE BGP Community? (Was: RTBH Support Across the Industry)

[Michael Hare via NANOG <nanog () lists nanog org>]

+1.  Was going to follow up to Saku's message about how/if folks are doing that in JunOS [or other OS] natively without 
outside automation.   Our backbone has scavenger style plp in BE, I control admission via prefix-list in ingress 
fwfilter on untrusted interfaces.  Haven't personally tested but looks like DCU + forwarding-table export policy + 
output firewall filter, maybe this is possible today but requires output fwfilter to family mpls.  I don't currently 
have a fwfilter there so ideally another option exists.

-Michael

> -----Original Message-----
> From: jim deleskie via NANOG <nanog () lists nanog org>
> Sent: Tuesday, August 4, 2026 9:00 AM
> To: North American Network Operators Group <nanog () lists nanog org>
> Cc: jim deleskie <deleskie () gmail com>
> Subject: Re: how about a well-known DOWNGRADE BGP Community? (Was:
> RTBH Support Across the Industry)
>
> I fully support this direction.
>
> Job, anything I can do to assist, let me know please
>
> -jim
>
> On Tue, Aug 4, 2026 at 9:38 AM Job Snijders via NANOG
> <nanog () lists nanog org>
> wrote:
>
> > Dear all,
> >
> > Following up on the RTBH thread, we'd like to put forward an different
> > strategy for DoS attack mitigation. Perhaps just as an extra tool in the
> > toolbox.
> >
> >    Abstract --
> >    This document outlines a method to mitigate Denial of Service (DoS)
> >    attacks by using a well-known BGP community named "DOWNGRADE" as
> signal
> >    to neighboring networks to treat traffic destined towards "DOWNGRADE"
> >    tagged IP prefixes with low precedence. The "downgrade" strategy
> >    offers an appealing alternative to Remote Triggered Blackhole (RTBH)
> >    filtering, because RTBH filtering completes the DoS attack and hampers
> >    the defender's ability to monitor whether the attack is still ongoing.
> >
> > Read the full draft document here:
> >
> >
> > https://urldefense.com/v3/__https://datatracker.ietf.org/doc/html/draft-
> spaghetti-grow-downgrade-bgp-
> community__;!!Mak6IKo!I84uSQpoZr3Hgeb0DCb0OohZiOXtp1cZcaeVckp1CLt4n
> T_niCJvjcUFGnTGsreTP8yeCSencjX90coak9bz$
> > Your feedback is most welcome!
> >
> > Kind regards,
> >
> > Job
> > _______________________________________________
> > NANOG mailing list
> https://urldefense.com/v3/__https://lists.nanog.org/archives/list/nanog@lists.n
> anog.org/message/UGA3PTY45ILBQRASIJJVHAF3M57MQQ5I/__;!!Mak6IKo!I84u
> SQpoZr3Hgeb0DCb0OohZiOXtp1cZcaeVckp1CLt4nT_niCJvjcUFGnTGsreTP8yeCSe
> ncjX90TqgTZE0$
> >
> _______________________________________________
> NANOG mailing list
> https://urldefense.com/v3/__https://lists.nanog.org/archives/list/nanog@lists.n
> anog.org/message/XQBBQVQTEKIECEDDE3TAE4BN2GQO5Q7Z/__;!!Mak6IKo!I8
> 4uSQpoZr3Hgeb0DCb0OohZiOXtp1cZcaeVckp1CLt4nT_niCJvjcUFGnTGsreTP8yeC
> SencjX90aGXE2jb$
_______________________________________________
NANOG mailing list 
https://lists.nanog.org/archives/list/nanog () lists nanog org/message/6QPXWXFIU7X6ANK33C5GSXXELAOBWQ6I/