Shim6 vs PI addressing

David Barak thegameiam at
Fri Mar 3 02:54:31 UTC 2006

--- Jared Mauch <jared at> wrote:
> 	I think you're missing that some people do odd
> things with their IPs as well, like have one ASN and
> 35
> different sites where they connect to their upstream
> all with the same ASN.  This means that their 35
> offices/sites
> will each need a /32, not one per the entire asn in
> the table.

No, that's an argument for a /32 and a bunch of /48
allocations heard by a single provider, who's getting
paid to carry them, but are not advertised to the rest
of the Internet.

> 	And they may use different carriers in different
> cities.  Obviously this doesn't fit the definition
> that some have
> of "autonomous system", as these are 35 different
> discrete networks
> that share a globally unique identifier of sorts.

Well, wait a minute - what would these people do
TODAY?  Some build tunnel backbones, some use one ASN
per city, some do "allowas-in" or other things of that
nature.  I would venture to say that most medium to
large enterprises don't use straight-Internet with no
VPN of any kind to support their enterprise backbones
anymore, simply for security reasons.  

My argument still stands - if having an ASN is equated
with having a routable netblock, then each of those
cases results in the enterprise being able to pass
packets, and only the "one ASN per city" approach
requires multiple netblocks.


David Barak
Need Geek Rock?  Try The Franchise:

Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 

More information about the NANOG mailing list