A prefix is a prefix. A route is a prefix plus a next-hop. Your next hop for your PNI is different than your IX.
I don't believe I advocated running IX links hot. Financially, as an IX operator, I'd prefer that people ran all their bits over an IX and that all links were best kept below 10% utilization. ;-) Obviously I know that's not good engineering or fiscally responsible on the network's behalf. Just going to the extreme to support my point.
From: "Mark Tinka" <mark.tinka@seacom.mu>
To: "Mike Hammett" <nanog@ics-il.net>
Cc: nanog@nanog.org
Sent: Thursday, January 31, 2019 8:14:44 AM
Subject: Re: Calling LinkedIn, Amazon and Akamai @ DE-CIX NY
On 31/Jan/19 15:54, Mike Hammett wrote:
Not all routes are created equal. If you
have a PNI and an IX connection of equal capacity, obviously the
IX connection will fill up first given that there is more
opportunity there.
I think you meant to say not all "paths" are equal. Routes are
routes. Where they lead to is another matter.
The presence of a PNI does not preclude good governance of an
exchange point link. If you are going to (willingly or otherwise)
ignore the health of your public peering links over your private
ones (or vice versa), then I wish upon you all the hell you'll face
that comes with taking that position.
Our policy is simple - 50% utilized, you upgrade. Doesn't matter
what type of link it is; WDM Transport, IP, peering (public or
private), Metro, core backbone, protection paths, e.t.c. Choosing to
let your public peering links run hot because your "major" peers are
taken care of by the private links is irresponsible. Do a lot of
networks do it; hell yes, and for reasons you'd not think are
obvious.
Also, there are more moving parts in an
IX (and accompanying route servers), thus more to go wrong.
Agreed, but that's not the crux of this thread (even though it's one
of the reasons we do not relay solely on RS's).
Mark.