Re: Networks ignoring prepends?

[James Jun <james.jun () towardex com>]

On Wed, Jan 24, 2024 at 08:16:56AM -0800, William Herrin wrote:
> On Wed, Jan 24, 2024 at 8:11???AM James Jun <james.jun () towardex com> wrote:
> > You (AS11875) have an operational need for good connectivity
> > into 3356 but, you made a poor purchasing decision by buying
> > IP transit for 11875 from a provider who has 10-AS path into
> > 3356 instead of <=3 AS path. You've done a _bad_ job here
> > in selecting an inferior pathway into 3356, and what you
> > SHOULD have done is to select an IP transit provider who
> > has an optimal AS-path into 3356 to meet your operational
> > need of having good connectivity into 3356.
>
> Sophistry. I buy IP transit from 3 providers, one of which has a 3 AS
> path to 3356.

Again you omit context.

We've already established as per the RFC, that calculation of degree of preference takes precedence over and overrides 
AS_PATH (Phase 1 decision).  

Therefore, let's rephrase what you've just said above:

You're buying IP transit from 3 providers, two of which are configured with the following known constraints:

- 20473 who buys from 1299, who has lower degree of preference into 3356, as 1299 and 3356 are interconnection (could 
be settlement-free or paid-peer) peering partners.
- 53356 who buys from 47787 as a prioritized downstream customer, and then 47787 too subsequently connects into 3356 as 
a prioritized downstream customer.

It's obviously clear that 53356 path you've bought has a priority ticket into 3356 no matter how inferior or long its 
AS_PATH may be, and the solution is right in front of you.  Next.

James