On 2/04/2007, at 3:32 PM, Alastair Johnson wrote:
Oldest path is configurable behavior - many people prefer the more deterministic lowest neighbor ID because it prevents neighbor triggered traffic switches.
But it's not disabled default. My bet is that most people don't really consider the pros/cons of each in great detail, and instead opt for just-make-it-go.
You're also assuming that all providers use the Route Servers and not bilateral peering; which is a risky assumption.
From what I've seen, bi-lateral peering across the IXes is becoming less and less common.
I'd generally assume anyone has a local_pref based on cost: ie:
(speaking of risky assumptions.. :-)
highest local_pref for customer (ie. "getting paid for") prefixes second highest for second lowest cost/efficiency (private peering) third highest for third lowest (public) fourth highest for transit (or other)
Which fixes any problems with AS_PATH length.
Of course, I've seen a lot of networks that don't do things that you and I take for granted, though :-)
You raise some valid points... except the prefix in question wasn't announced by any peer that I could see in any case, so there was no determination being made.
Yep, the APE looking glass doesn't show any announcements either. Based on your assumptions, it appears that you're much more of an optimist than I. -- Nathan Ward