North American Network Operators Group

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Re: classful routes redux

  • From: Stephen Sprunk
  • Date: Mon Nov 07 14:40:29 2005

Thus spake <[email protected]>
One way to visualize this is to imagine the Internet
as a cloud. At the core of the cloud are the core
providers and at the edge of the cloud are the end
user organizations, many of which appear to be
singly homed. However, hidden behind this edge is
a thin layer which represents a private internet.
It also connects many networks but it does *NOT*
exchange traffic with the public Internet. All the
networks connected to these private internets are
also connected to the public Internet but they
implement strict traffic separation policies
internally. In some cases, this is an air gap but
these days it is often a bunch of firewalls.
And let's not forget that various parts of that "thin layer" connect to each other in something approaching a partial mesh with no transitive reachability.

While I doubt that it's anywhere near enough to account for all the "MIA" ASNs, nor do we have any way of knowing for sure, but many of those folks cannot get by with private ASNs for those networks for the same reason they can't use RFC1918 space. Others give in and use static routes and double-NATs.


Stephen Sprunk "Stupid people surround themselves with smart
CCIE #3723 people. Smart people surround themselves with
K5SSS smart people who disagree with them." --Aaron Sorkin