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/