I’d bet that 47787 is a paying century link customer. As such, despite the ugliness of the path, CL probably local prefs everything advertised by them higher than any non-paying link. I’m willing to bet 1299 is peered and not paying CL.

It's almost as if you've done this before. :)

Community : 3356:3 3356:22 3356:100 ==> 3356:123 <++ 3356:575
3356:903 3356:2011 3356:11918 47787:1020
47787:3090 47787:3690 47787:30000
Cluster : 0.0.7.15 0.0.7.19
Originator Id : 4.69.181.14 Peer Router Id : 4.69.130.10
Fwd Class : None Priority : None
Flags : Used Valid Best IGP Group-Best
Route Source : Internal
AS-Path : 47787 47787 47787 47787 53356 11875 11875 11875

3356:123 = Customer

On Mon, Jan 22, 2024 at 5:45 PM Owen DeLong via NANOG <nanog@nanog.org> wrote:

I’d bet that 47787 is a paying century link customer. As such, despite the ugliness of the path, CL probably local prefs everything advertised by them higher than any non-paying link. I’m willing to bet 1299 is peered and not paying CL.

Sending bits for revenue is almost always preferable to sending bits for free, so…

Owen

> On Jan 22, 2024, at 12:37, William Herrin <bill@herrin.us> wrote:
>
> On Mon, Jan 22, 2024 at 10:19 AM James Jun <james.jun@towardex.com> wrote:
>> So, as a customer, you actually SHOULD be demanding your ISPs
>> to positively identify and categorize their routes using local-pref
>> and communities.
>
> Hi James,
>
> The best path to me from Centurylink is: 3356 1299 20473 11875
>
> The path Centurylink chose is: 3356 47787 47787 47787 47787 53356
> 11875 11875 11875
>
> Do you want to tell me again how that's a reasonable path selection,
> or how I'm supposed to pass communities to either 20473 or 53356 which
> tell 3356 to behave itself?
>
> Regards,
> Bill Herrin
>
>
> --
> William Herrin
> bill@herrin.us
> https://bill.herrin.us/