Re: Setting sensible max-prefix limits

[Steve Lalonde <steve () enta net>]

On 18 Aug 2021, at 10:33, Lars Prehn <lprehn () mpi-inf mpg de <mailto:lprehn () mpi-inf mpg de>> wrote:
> As I understand by now, it is highly recommended to set a max-prefix limit for peering sessions. Yet, I can hardly 
> find any recommendations on how to arrive at a sensible limit.
>
> I guess for long standing peers one could just eyeball it, e.g., current prefix count + some safety margin. How does 
> that work for new peers? Do you negotiate/exchange sensible values whenever you establish a new session? Do you rely 
> on PeeringDB (if available)? Do you apply default values to everyone except the big fishes?
>
> Apart from your peers, do you also apply a limit to your transit sessions?

We always use PeeringDB data and refuse to peer with networks not in PeeingDB ( I think there are only 2 exceptions ) 
Automation keeps the max_prefix numbers up to date. 

Our transits we use data from the weekly routing table reports and allow some expansion room.

So far this works for us

Regards

Steve