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

Mon Nov 29 16:41:27 UTC 2004

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>

> > 32bits ASN would thus just mean the end of BGP...
> >
> ULA will do much more damage than 32 bit ASNs.

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.

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.

Greets,
 Jeroen

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