Nathan Ward wrote:
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.
Perhaps. However the 'default' you refer to is also not common to all vendors, however. I would be interested to know how many people (ISPs) do elect to use "bgp bestpath compare-routerid" on their Cisco equipment. I'd imagine smaller/less experienced ASNs probably do leave it, but I suspect one or two ISPs may well have changed it.
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.
Admittedly I haven't necessarily been near an IX recently, but I can't see bilateral going away fast - most people at APE seemed to prefer it when I had anything to do with configuring BGP. ihug's policy notwithstanding anyway.... There are IXs around that certainly enforce the behavior though, and it's one I have always wondered about for precisely this reason: the additional AS in the path introduces too many potential opportunities for the IX to be non-preferred in a default environment.... which is bad.
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.
Which is one of the things I checked before posting to start with :P.
Based on your assumptions, it appears that you're much more of an optimist than I.
The glass is merely twice as big as it should be. aj. -- Am I really losing my negativity? This cannot go on.