[arin-ppml] Multihomed Microallocations

William Herrin bill at herrin.us
Tue Aug 4 17:05:24 EDT 2009

On Tue, Aug 4, 2009 at 4:48 PM, Kevin Kargel<kkargel at polartel.com> wrote:
> The only way (to my understanding and as I was told last week) to get a
> fully functional redundancy model without LOTS of silly router tricks is for
> the customer to have their own ASN.  When they have their own ASN I could
> de-aggregate what I allocate to them, but once they have their own ASN
> anyway then the 'might as well have their own netblock' comes in to play.

Technically there is one additional way but it has all the
disadvantages of the customer using his own ASN plus an extra couple.
The customer can advertise his route to you using a private ASN. You
then strip the private ASN from the route so that it leaves your
network with your ASN as the origin. He does the same with his other
ISP, so the addresses originate from that network apparently from the
other ISP's ASN. As a result you have a route in the table apparently
from two different ASN's but really from a private ASN sitting behind
both of them.

Not a lot of folks do this. The only real gain from it is that it
preserves the customer's anonymity to limited degree while still
allowing them to multihome. It does not allow aggregation or keep any
routes out of the table.

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

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