AS PATH limits

Ken Chase math at
Fri Dec 22 23:04:16 CST 2017

Push harder on upgrading. "Dec 30" is my earliest window I got from my customer
after previously pushing with previous events (didnt help that Cogent said "yeah
we agree these are silly, we'll be filtering more aggressively" -- this time it
snuck in from the less busy side of our network).

It's not even going to be service impacting, if we do everything correctly,
but *who knows for sure* :) Course more long path events occurring ARE service
impacting more than the risk during upgrade, so go figure.

Customers! Cant live with em, cant afford to live without em!

Nonetheless, I do think that backbones should be filtering ridiculous AS paths
just as a matter of course. Everyone fix their own stuff, and everyone help
the next guy downstream by stomping on sillyness. Generally been an internet mindset
that I've seen since even before the great renaming...


On Fri, Dec 22, 2017 at 05:50:36PM -0500, William Herrin said:
  >On Fri, Dec 22, 2017 at 5:45 PM, Nick Hilliard <nick at> wrote:
  >> William Herrin wrote:
  >> > The AS path lengths we're talking about are unreasonable.
  >> "unreasonable" is a peculiar word to use here :-)
  >> It's the internet and you can't expect other people not to do silly
  >> things from time to time.  This is a known problem and it isn't even the
  >> first time it's been discussed on nanog-l.
  >> If you've been hit with a known service-affecting problem that can
  >> easily recur without warning and which will be service affecting if it
  >> hits again, common sense suggests that it would be a good idea to
  >> upgrade to a version of code which isn't affected.
  >Well, that's a brilliant platitude, but what do you do when it breaks over
  >and over until the other guy upgrades?
  >William Herrin ................ herrin at  bill at
  >Dirtside Systems ......... Web: <>

Ken Chase - math at Guelph Canada

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