Use of Default in the DFZ: banned in philly, see it now on the net!

Ren Provo ren.provo at
Tue Jun 23 23:11:56 UTC 2009

One point of clarity here.  Lightning talks are scheduled in a more spur of
the moment fashion than the traditional submission process for general
sessions.  We often schedule lightning talks around a topic with potential
to run short if Q&A isn't significant or we have a 15 minute gap before a
break.  Unfortunately that means dates, or times, have the potential to
shift and flexibility is required by the party presenting.  Randy was
offered an alternative as soon as it was discovered the original time slot
on Monday was not going to prove viable.  Options later in the meeting were
not chosen by Randy due to his schedule constraints.  If a specific date is
required on the NANOG agenda please consider submitting a presentation well
in advance of posted deadlines for the general sessions.  The NANOG PC does
consider comments made in the tool at when scheduling
the agenda.  Short duration presentations have been accepted well in advance
of the meeting for about a year now and we welcome interesting topics, much
like Randy details below.  We hope to see Randy back up at the microphone on
stage at future NANOG meetings.  Cheers! -ren

On Tue, Jun 23, 2009 at 3:51 PM, Randy Bush <randy at> wrote:

> due to nanog pc silliness, my lightning talk on $subject was not given
> in philly.  i had promised to report to nanog the results of our winter
> experiment which used as path poisoning.  here is the lightning talk i
> would have given.
> this is really meant to be a talk, so the slides can be a bit hard.
> on slide 6
>  /20 is the as path length of a /20, i.e. a 'normal' distribution,
>      as seen from bgp monitors at RV, RIS, and a jillion others
>  /25 is the as path length distribution we saw pinging from the /25
>  BGP is the as path length distribution we saw from RV/RIS
> i.e. BGP views are significantly skewed.  but most of us knew that.
> on slides 10 and 11, the categories stub, small isp, large isp are from
> a ucla study.  imiho, you should take them with a grain of salt.
> on 12, the reason for the funniness around 30 test points is because, we
> really wanted >= 30 test points in an AS.  so if we got close, we
> scanned harder to find them.
> please do check your as at <> and then actually
> look at your router config.  i found one of my routers still had a
> default from when i was bringing it up.
> randy

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