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

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

Saku-

Thanks for link.  This is what I had in mind, but I presumed if output interface was into an LSP maybe I'd need output 
filter in family MPLS.  At this point, I'll just try this out in the lab.

-Michael

> -----Original Message-----
> From: Saku Ytti <saku () ytti fi>
> Sent: Tuesday, August 4, 2026 11:30 AM
> To: North American Network Operators Group <nanog () lists nanog org>
> Cc: Michael Hare <michael.hare () wisc edu>
> Subject: Re: how about a well-known DOWNGRADE BGP Community? (Was:
> RTBH Support Across the Industry)
>
> On Tue, 4 Aug 2026 at 18:20, Michael Hare via NANOG
> <nanog () lists nanog org> wrote:
>
> > +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.
>
> Something to this note, nothing really specific to any AFI:
> https://urldefense.com/v3/__https://raw.githubusercontent.com/job/draft-
> downgrade-bgp-
> community/refs/heads/main/nos/junos.txt__;!!Mak6IKo!IOVZQT4Lf7E7zL5MWS
> bICpNXJnyzuaVs2NnLxqdQJftUH3NI3k00Ws0VNddwQDb250bo4F95RdUFgnqM$
>
> For context, remainder of QoS config would look something to:
> https://urldefense.com/v3/__https://p.ip.fi/Nott.txt__;!!Mak6IKo!IOVZQT4Lf7E7
> zL5MWSbICpNXJnyzuaVs2NnLxqdQJftUH3NI3k00Ws0VNddwQDb250bo4F95Rb4
> m1HQV$
>
>
>
> --
>   ++ytti
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