disconnected autonomous systems

Adam Bechtel abechtel at inktomi.com
Wed Nov 13 20:53:52 UTC 2002

I don't know how much of it is ignorance, or resource constraints.  I've
worked with companies that have used disconnected AS's because they couldn't
justify multiple AS's and they needed to multihome in multiple isolated
locations.  I've also worked with companies that deliberately de-aggregate
prefixes due to link capacity issues.  Network operators have to balance
building an ideal network to what equipment, links, IPs and AS's they can
justify.  I personally rather see network operators de-aggregate and utilize
space efficiently as opposed to hoarding larger prefixes to make their
network appear like something it isn't.


-----Original Message-----
From: owner-nanog at merit.edu [mailto:owner-nanog at merit.edu]On Behalf Of
Ralph Doncaster
Sent: Wednesday, November 13, 2002 11:46 AM
To: nanog at merit.edu
Subject: disconnected autonomous systems

I've found there are many providers that have completely disconnected
autonomous systems.  For example Yipes (6517) uses L3 on the west coast
and Williams on the east coast. is advertised under their AS through WCG and is advertised under their AS through L3.

And the number of connected autonomous systems with de-aggregated
prefixes appears to be even more common than a disconnected AS.

It would seem that many (most?) network operators are just ignoring the
more vocal opinions on NANOG.


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