[157911] in North American Network Operators' Group
Re: What is BCP re De-Aggregation: strict filtering /48s out of /32
daemon@ATHENA.MIT.EDU (Michael Smith)
Wed Nov 14 18:32:02 2012
From: Michael Smith <mksmith@mac.com>
In-reply-to: <CAP-guGWryM-uj6yaxf1-ZnJp8z6x7=9wcowYnB=Lf366ftcUsw@mail.gmail.com>
Date: Wed, 14 Nov 2012 15:31:44 -0800
To: William Herrin <bill@herrin.us>
Cc: "nanog@nanog.org" <nanog@nanog.org>, Michael Smith <mksmith@mac.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Nov 14, 2012, at 1:50 PM, William Herrin <bill@herrin.us> wrote:
> On Wed, Nov 14, 2012 at 3:10 PM, Michael Smith <mksmith@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.
>
Again, I thought the discussion was about PI, not PA. I don't announce any PA.
> 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.
>
You have great confidence in the immutability of design and the description thereof.
Mike
