This leads to the first (and I think most urgent problem) taking a look at the rate ASN's a assigned nowadays. In rough numbers there're about 10.000 ASN not being visible in the routing table. And like someone else already mentioned in the 'multi-homing v6' discussion, how many of the newly handed out ASN are really required for multihoming ?
There are a thousand ways in which an ASN used for multihoming between two upstreams will fail to appear in RIS or routeviews. If anybody is really serious about figuring out what is going on, then they will do a REAL research project using telephone and email to contact the human beings who know the facts behind the use of these ASNs. No doubt some of those human beings will confirm that an ASN is no longer in use, but many others will point out how their ASN is in use even if it is invisible to crude 3rd party probing technology.
During my years in ISP networking bussiness I've more than once come upon a network with fake entries and customers/potential customers multihoming to one upstream and asking for an ASN request with a second upstream being 1/50th to 1/10th of the primary bandwidth to satisfy requirements.
Sounds to me like a live circuit plus a failover circuit. Some people call this good engineering.
These setups I'm almost sure don't need an ASN.
If they were engineered to use BGP then they definitely do NEED an ASN. If you are saying that they should be engineered differently, then I have to ask you to move your discussion to RIPE's "ISP Engineering rules" working group because you have gone beyond IP addressing policy.
So first point to consider when talking 'needless' resources is: how to possibly limit the number of multihoming-ASN handed out to the ones really needed and how to move people to hand them back when no longer needed ?
No, actually the first point to consider is whether or not recovering every last "missing" ASN will solve the ASN shortage problem. People did consider this and the answer was NO. Therefore, the focus has been on making longer ASNs rather than recovering the few missing ones.
Although in v4 world, RFC1918 & NAT are a fine thing to conserve address space, but forcing their use would be dictating others how to operate their network.
I suppose that you don't believe in dictating how people should operate their networks? What about how people should engineer their networks? --Michael Dillon