Private ASN space

[Jimmy Kyriannis]

At 12:37 AM -0400 7/20/99, Craig Metz wrote:
>  Would someone kindly remind me what the reserved-for-private-use ASNs are?
>
>  I need an ASN for use with my 6Bone routers (my == me, not NRL), and getting
>a "real" one is well outside my budget. Barring constructive objections, I'd
>like to claim one of the private ones for this purpose.
>
>									-Craig

In a nutshell, it means that "reserved-for-private-use ASNs" are reserved
for internal use on an enterprise network, but may not be used on the
Internet at large.  To the Internet, an enterprise has only one ASN that's
advertised to all routers on the backbone.  However, a problem arises when
some large networks use an EGP (such as BGP) internally to aggregate large
routing tables and establish routing policies between sections of the
network.  When used internally with the enterprise, some BGP configurations
require multiple ASNs to be used in order to achieve certain functionality.
Hence, a dilemma: an enterprise has only one ASN, yet may need more than
one to achieve certain routing topologies within.  This is solved through
the use of these private ASNs; they can be used safely within an enterprise
network, however, may not be used for reachability advertisements to the
Internet at large.

Sorry if this slightly of-topic, but hopefully answers the question raised.


Jimmy