Open letter to Level3 concerning the global routing issues on June 12th

Sat Jun 13 14:16:18 UTC 2015

On Sat, 13 Jun 2015, Mark Tinka wrote:

> For peering and customers, we set a default prefix limit value for IPv4
> and IPv6. We only change this if the peer/customer informs us that they
> will announce a lot more than what we've configured. We add some % to
> cover for "sudden" growth, but not too much to impact the network.
>
> For customers, we add prefix lists and AS_PATH filters as mandatory.
>
> I'm sure others do the same. It would be good if we all did.
>
> I know the largest transit providers tend to be more relaxed for various
> reasons. Some rely on filters generated by IRR entries, others don't.
>
> A lot more work is needed, indeed. It's not 2008 anymore...

At my previous job (regional ISP with a decent amount of BGP-speaking 
downstream customers), we did prefix and AS-PATH filtering on all customer 
sessions.  The only thing lacking at that time (1997-2004) was a decent 
way to automate changes - everything was pretty manual.  That said, it 
kept issues caused by customers leaking routes back to us down to pretty 
much nil.

jms