Some terms should be unified, e.g., "upstream" "upstream provider"; "Internet peer" "lateral peer" "peer"; etc.

On 26/10/2023 15:10, Tobias Fiebig wrote:
 > [..]
 >
>> The global limits seem to offer no real benefit in addition to
>> per-session limits. The referenced paper mentions Per-Origin AS
>> limits, not the per-Neighbor AS limits mentioned in the draft. This
>> also seems to be unimplementable, given that routers act
>> independently on prefixes they receive.
>
> I think there are two points in here:
> - The paper mentions per-origin, which i consider even more un-
>    implementable than per-neighbor, which is why I restricted it to
>    direct neighbors (similar to the idea of BCP38, that things 'should'
>    be fine if everyone filters their downstreams.)
> - Your implementability point is very valid.
>
> To address both points, it might make sense to move this to a softer
> recommendation to "Monitoring the global number of prefixes ingested
> from each peer/downstream, and alerting if that number increases too
> quickly" or something similar;

I think a recommendation for prefix limit monitoring and alerting for
all peers would be a good replacement of section 8.2.2.

Section 8.2.1 already mentions placing a prefix limit on upstreams, so
this should limit the risk of the attack described in 8.2.2 somewhat.
But it will have to be combined with monitoring, so that a customer AS
does not cut itself off if the BGP table on all of their upstreams
eventually grows too large.

Kind regards,
Martin