Re: Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market

[William Herrin via NANOG <nanog () lists nanog org>]

On Wed, Oct 28, 2026 at 12:43 PM Patrick W. Gilmore via NANOG
<nanog () lists nanog org> wrote:
> For Josephina’s elucidation: Most networks will send traffic over
> free peering before transit, even if peering is much high latency.
> In fact, they are unlikely to even know the transit link is lower latency
> as they will not even check. In their defense, peering is typically
> equal or even lower latency, but not always.

Hi Patrick,

Close but not exactly. Most optimize for revenue, then cost. And when
they're done with that, they might deign to look at the length of the
BGP AS path. Only a few pay attention to latency, loss or hop count at
all.

Revenue: does one of our customers announce a route to that IP
address? We don't care how bad that route is; use it.

Cost: does one of our free peers announce a route to that IP address?
Prefer it over an upstream transit we have to pay for.

It's always fun when one of the ISPs decides the best route from
Seattle to Seattle is via New York City just because that's how their
money happens to flow.

Regards,
Bill Herrin


-- 
For hire. https://bill.herrin.us/resume/
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