Networks ignoring prepends?

Tue Jan 23 17:03:09 UTC 2024

>
> 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 at nanog.org>
wrote:

> > > William Herrin <bill at 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.
>
>
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