North American Network Operators Group
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Re: Has PSI been assigned network 1?

  • From: Vadim Antonov
  • Date: Fri Apr 21 20:45:38 1995 
Karl, you obviously do not understand what global networking
and policy routing mean.

Right today we nearly killed all Internet by _not_ doing
paranoid filtering on ANS route announcements (well we
couldn't do it because of certain contractual obligations).

ANS had trouble with generating configuration for ENSS 147,
so they simply dropped all routes at our MAE-East+ box
without filtering they usually do,  which would be fine if we
didn't do some upgrades at ICM, which involved changing
preferences in ICM-SL routing, to the effect that SL started
preferring AS 690 as path to many European networks. It resulted
in SprintLink -> Europe traffic being moved from SL->ICM FDDI
connection to SL->ENSS(147)->ANS core->Dante path; which at
the daytime grew and turned out be enough to overload ENSSes
along the path.

This resulted in ENSS 147 delaying BGP keealives for so long
that MAE-E peers (including SprintLink) were dropping
their BGP sessions, only to reset them later.  Since that
causes route caches being flushed all _other_ ciscos were
falling back to switching by CPU, became overloaded and
started dropping their BGP sessions.  Which resulted
in snowball of real massive routing flap.

I imagine how Internet would work if everybody listened to
the enlightened advice of our esteemed sage:

>Fascistic filtering breaks connectivity.
>
>So you trade a *risk* of broken connectivity for KNOWN broken connectivity?
>
>Sounds like a poor trade to me, and one which, undertaken consciously and
>with knowledge of the repercussions, leaves you with being less than a full
>Internet connectivity provider.
>
>After all, if you're filtering perfectly valid announcements then you are,
>by definition, not providing connectivity to the "whole Internet" to the
>best of your ability, are you?

Sorry, Karl.  Internet is lucky that people who run most big networks
know better than to wait for shit to happen.  In the system as large
as Internet shit happens permanently.  Somewhere, in the most
unxpected places.

If you persist in your dislike of filtering i guess i'll purely
accidentally misconfigure a static route, so it will be the the same
as your backbone address.  RS won't save you.

This is a joke, of course.

--vadim