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Re: 16 vs 32 bit ASNs [Re: BBC does IPv6 ;) (Was: large multi-siteenterprises and PI]

  • From: Owen DeLong
  • Date: Mon Nov 29 12:59:31 2004


--On Monday, November 29, 2004 5:41 PM +0100 Jeroen Massar <[email protected]> wrote:

On Mon, 2004-11-29 at 08:35 -0800, Owen DeLong wrote:

> Also, with 32bit ASN's, also expect upto 2^32 routes in your routing
> table when each and every ASN would at least send 1 route and of course
> there will be ASN's sending multiple routes.
>
Only if EVERY ASN were allocated and active.

*BUZZZ* ASN's are a globally unique resource, you not seeing it does not
mean that it is not in use. For that matter anything from a prefix to a
ASN that any of the RIR's hands out does not have to show up on the
public internet, it could even be used by a single company internally,
just like RFC1918 prefixes, or on a VPN etc.

<SNIP>
Duh... You're making my point for me. There won't be 2^32 routes from 1 route
per ASN unless ALL 2^32 ASNs are assigned.

Further, lots of ASNs get used for things that don't put routes in the global
table. (If I can't see it, it's not in the global table).

Which damage might that be? The prefixes are not supposed to be put in
the global routing table and even if people did, with 16bit ASN you only
allow 65536 routes, which is less than current IPv4... oops let's
disable repeat mode... also see my nice comment on 6to4, that is more
useful if you want a globally unique /48 for sure, that is if you really
'own' the IPv4 space of that prefix.


But, that "should" becomes a purely artificial barrier which will be
eliminated by market economics. Finally, with the limitations of
16 bit ASNs (which we will surpass regardless of reclamation), we won't
likely end up with 1 prefix per ASN.  The prefixes will be out there
regardless of the number of ASNs that end up originating them.


For that matter Ford and some other /8's are only 2002:13::/24, which is
the same size as the 6bone space that was handed out early on. Do also
realize that if this all becomes a peep-up and the RIR's (or actually
IANA) runs out of space that they can try all over 7 more times, *that*
is how much IPv6 space is available.


And?


Owen

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

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