I feel your pain Bill, but from a slightly different angle.  For years the large CDNs have been disregarding prepends.  When a source AS disregards BGP best path selection rules, it sets off a chain reaction of silliness not attributable to the transit AS's.  At the terminus of that chain are destination / eyeball AS's now compelled to do undesirable things out of necessity such as:
  1) Advertise specifics towards select peers - i.e. inconsistent edge routing policy & littering global table
  2) Continuing to prepending a ridiculous amount anyway
Gotta wonder how things would be if everyone just abided by the rules.

What 'rule' are you asserting is being broken here? 

 

On Mon, Jan 22, 2024 at 9:56 PM Jeff Behrns via NANOG <nanog@nanog.org> wrote:
> > William Herrin <bill@herrin.us> wrote:
Until they tamper with it using localpref, BGP's default behavior with prepends does exactly the right thing, at least in my situation.

I feel your pain Bill, but from a slightly different angle.  For years the large CDNs have been disregarding prepends.  When a source AS disregards BGP best path selection rules, it sets off a chain reaction of silliness not attributable to the transit AS's.  At the terminus of that chain are destination / eyeball AS's now compelled to do undesirable things out of necessity such as:
  1) Advertise specifics towards select peers - i.e. inconsistent edge routing policy & littering global table
  2) Continuing to prepending a ridiculous amount anyway
Gotta wonder how things would be if everyone just abided by the rules.