What is BCP re De-Aggregation: strict filtering /48s out of /32 RIR minimums.

Wed Nov 14 21:50:43 UTC 2012

On Wed, Nov 14, 2012 at 3:10 PM, Michael Smith <mksmith at mac.com> wrote:
> I guess I'm confused.  I have a /32 that I have broken up
> into /47's for my discrete POP locations.  I don't have a
> network between them, by design.  And, I won't
> announce the /32 covering route because there is
> no single POP that can take requests for the entire
> /32 - think regionalized anycast.
>
> So, how is it "worse" to announce the deaggregated
> /47's versus getting a /32 for every POP?  In either
> case, I'm going to put the same number of routes into the DFZ.

Hi Michael,

If you announce an ISP /32 from each POP (or an end-user /48, /47,
etc) then I know that a neutral third party has vetted your proposed
network configuration and confirmed that the routes are disaggregated
because the network architecture requires it. If you announce a /47
from your ISP space, for all I know you're trying to tweak utilization
on your ISP uplinks.

In the former case, the protocols are capable of what they're capable
of. Discrete multihomed network, discrete announcement. Like it or
lump it.

In the latter case, I don't particularly need to burn resources on my
router half a world away to facilitate your traffic tweaking. Let the
ISPs you're paying for the privilege carry your more-specifics.

Regards,
Bill Herrin

-- 
William D. Herrin ................ herrin at dirtside.com  bill at herrin.us
3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004