Networks ignoring prepends?

Wed Jan 24 08:54:56 UTC 2024

BGP is more of a PDVP (Policy Distance Vector Protocol). Policy will always override Distance in BGP and is pretty much the key difference between an EGP and an IGP. 

Once you recognize that, the rest makes much more sense. 

Owen

> On Jan 23, 2024, at 14:29, William Herrin <bill at herrin.us> wrote:
> 
> On Tue, Jan 23, 2024 at 12:34 PM Niels Bakker <niels=nanog at bakker.net> wrote:
>> BGP, while a distance vector protocol, famously does not take
>> latency into account when making routing decisions.
> 
> Unless overridden, BGP takes -distance- into account where distance =
> AS path length.
> 
> Centurylink has overridden that with a localpref so that it DOES NOT
> take distance into account. Which rather defeats the function of a
> distance vector protocol.
> 
> Regards,
> Bill Herrin
> 
> 
> --
> William Herrin
> bill at herrin.us
> https://bill.herrin.us/