North American Network Operators Group

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Re: long as path games?

  • From: Blaine Christian
  • Date: Tue Feb 01 11:04:36 2005

> so, 'dumb' but not 'invalid'... There might very well be networks (say not
> on the internet) where as-paths longer than 100 might be required. Saying:
> "they are invalid" isn't correct. Saying: "The use of as-path longer than
> 100 on today's Internet isn't helpful" is correct, or so say you and
> atleast blaine.

All I can honestly say is that I never saw valid advertisements > 100 used
on the Internet.  I can not think of a good use in the Internet provider
space for an AS that long but who knows what may happen in the future.  The
reason we set it to 100 was that we wanted to give plenty of room for
growth; realizing we were not going to be perfect about predicting future
needs.  We could have set it lower but 100 was a nice round number <grin>.

I stopped recording all advertisements a few months ago but I suspect we are
still sub 50 and I am sure someone on this thread probably has that info at
their finger tips.

Since the bug itself revolved around an 8 bit variable it may even be safe
to set things at 200.  If you are in a core role and you set the limit at
something like 254 you may have trouble prepending your AS as it could tip
you over the edge (WRT the potential for triggering that specific bug).

Regards and, I believe, congratulations Chris!


P.S. Nothing in the above constitutes a recommendation to apply
configurations to routers.  Use your own judgement and track your BGP table
for a few months before playing with these knobs.