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RE: IXP hardware



continuing the barry and randy act ...

and three years ago, you were recommending layer three exchanges.
:-)

recent measurement has shown that the problem with route reflectors
is that they act as serious announcement amplifiers.  this seems to
be due to a trade-off made in some bgp implementations where it is
perceived as easier (and maybe more reliable, dunno) to allow many
duplicate announcements as opposed to spending the code and extra
processing to eliminate them.  we have frequent traces of 4-6
duplicate (in all attributes) announcements.  ugly!

route servers won't change the number of routes i receive.  they
just change the number of direct peers.  and, in doing so i get a
single point of failure for the whole exchange, and a bunch of
creaky software that has to be configured and maintained.  and
simple hacks to do route servers insert an AS in the middle, which
can, in some circumstances, defeat the exchange as the costly
international links might win the bgp routing tie-breaker.

but what's interesting is that, on a nice simple layer two
exchange, one can have
  o some peers who peer directly, the old-fashioned way
  o a route reflector for those who want to play with that
  o a route server for those who want to play with that

my memory is that you have something like a 17xx router which has
the memory for a dozen or more peers and is relatively inexpensive.

randy

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