nanog mailing list archives

Re: Shim6 vs PI addressing


From: Owen DeLong <owen () delong com>
Date: Thu, 02 Mar 2006 13:31:35 -0800



--On March 2, 2006 9:37:12 AM -0500 Jared Mauch <jared () puck nether net>
wrote:

On Wed, Mar 01, 2006 at 03:01:22PM -0800, Owen DeLong 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 Tier69.net
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.

People who are doing that have not read the definition of the
term ASN and there is no reason that the community or public
policy should concern itself with supporting such violations
of the RFCs.  An AS is a collection of prefixes with a consistent
and common routing policy.  By definition, an AS must be a
contiguous collection of prefixes or it is not properly a
single AS.  Using the same ASN to represent multiple AS is
a clear violation.

It doesn't fit the RFC definition of AS.  Therefore, there is no
reason to support such usage on a continuing basis.  You violate
the RFC's you takes your chances.

      I guess all those root servers that use the same asn
but connect to different networks (anycast) should get shut down
quickly.

No... In the case of anycast, there is a consistent routing policy
for the address.  There are services that don't work because
of that routing policy, but, that's a decision of the service
provider in question.  However, they are using the equivalent
of one /32 per entire ASN, not one per site.

If they are advertising different prefixes from different sites
in an inconsistent manner using the same ASN, that is broken.
That's not what anycast does.

      This is a part of networking life today in the v4 space,
and without any current changes, it will (is) the same in v6
routing as there is nothing different except a few more bits 32 => 128.

Anycast is part of networking life today.  What you described initially
is _NOT_ how anycast works.

Owen

-- 
If it wasn't crypto-signed, it probably didn't come from me.

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