[151029] in North American Network Operators' Group
Re: filtering /48 is going to be necessary
daemon@ATHENA.MIT.EDU (Owen DeLong)
Sat Mar 10 01:52:28 2012
From: Owen DeLong <owen@delong.com>
In-Reply-To: <596B74B410EE6B4CA8A30C3AF1A155EA09D0C786@RWC-MBX1.corp.seven.com>
Date: Fri, 9 Mar 2012 22:48:31 -0800
To: George Bonser <gbonser@seven.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mar 9, 2012, at 7:08 PM, George Bonser wrote:
>> Owen said:
>>=20
>> 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.
>=20
> 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.
>=20
> 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
