Re: filtering /48 is going to be necessary

[Owen DeLong <owen () delong com>]

On Mar 9, 2012, at 7:08 PM, George Bonser wrote:

> > Owen said:
> >
> > I'm not a big fan, either, but, I think that the concept of "be
> > conservative in what you announce and liberal in what you accept" has
> > to apply in this case. Since it is a common (quasi-)legitimate
> > practice, arbitrarily filtering it is ill-advised IMHO.
>
> While I agree in principle, 16 bits of disaggregation has the potential for a lot of mayhem and 32 bits (accepting 
> /64 from PA) would be catastrophic.  This would seem to be a case where upstream providers can assist the end user in 
> obtaining their own PI space if they wish to multihome.  It would be in the provider's interest as it would reduce 
> the number of potential complaints from customers concerning multihoming problems.
>
> I filter /32 from PA space and am currently filtering one route but since the aggregate it is from has the same next 
> hop and since I don't see the route from anyone else, I'm not worried about it.

I haven't heard anyone advocate accepting less than a /48. I think /48 is a reasonable "You must be this tall to ride" 
barrier.

Beyond that, YMMV.

Owen