North American Network Operators Group

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Re: Anycast 101

  • From: Paul Vixie
  • Date: Fri Dec 17 16:59:52 2004

> > as i said the other day, "all power tools can kill."  if you turn on
> > PPLB and it hurts, then turn it off until you can read the manual or
> > take a class or talk to an expert.  PPLB is a link bundling technology.
> > if you turn it on in non-parallel-path situation, it will hurt you, so,
> > "don't do that."
> Yes, per packet load balancing will cause reordering, and if that's an 
> issue you shouldn't use it.  But if with pplb packets end up at two 
> different hosts, that's not the fault of the people who invented per 
> packet load balancing or the people who turned it on, but the fault of 
> the people giving the same address to two different hosts.

since i already know that Iljitsch isn't listening, i'm not interested in
debating him further.  i would be interested in hearing from anybody else
who thinks that turning on pplb in a eyeball-centric isp that has multiple
upstream paths is a reasonable thing to do, even if there were no anycast
services deployed anywhere in the world.  at the moment i am completely
certain that turning on pplb would be an irrational act, and would have a
significant performance-dooming effect on a client population behind it,
and that the times when pplb would actually be useful and helpful are very
limited, and that anycast doesn't even enter into the reasons why doing as
Iljitsch paints would be a bad idea.

but my mind is open, if anyone can speak from experience on the matter.
Paul Vixie