Re: Networks ignoring prepends?

[Darrel Lewis <d () rrel me>]

> On Jan 22, 2024, at 6:53 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.

One might argue that the global routing system should allow for sites to signal their ingress traffic engineering 
preferences to remote sites in ways other than bloating the global routing table.  But that ship seems to have sailed.

Regards,

-Darrel