On 2019-05-30 20:00 +0000, Mel Beckman wrote:
I’m sure we can find corner cases, but it’s clear that the vast ^^^^^ majority of BGP users are following the standard.
"Citation needed". :-) How is it clear that the vast majority are following this? I wouldn't be at all surprised if it *is* literally true; e.g, quite a lot of BGP users are probably single-homed and thus are forced to use private ASNs for talking BGP to their ISP; and lots of BGP users are also single-site, and don't engage in traffic engineering. But those cases are also not very interresting for this. It is more interresting to look at those that according to RFC 1930 *should* use multiple ASNs; how many of those *do* have separate ASNs for each group of prefixes with a "single and clearly defined routing policy", and how many *don't*? Any organization that has multiple sites with their own Internet connections, would then need an AS number for each site. How many people follow that? Can I get multiple ASNs from RIPE/ARIN/et.c for this case? (That's an honest question; the policies I found does mention sites or connected groups of networks, but they also mention organizations in a way that makes me wonder.) As others have mentioned, if you do traffic engineering by announcing prefixes with e.g. different BGP communities, or different amounts of ASN prefixing, you should according to RFC 1930 get a separate ASN for each unique combination of communities and ASN prefixing. Will RIPE/APNIC/et.c grant us multiple ASNs for that? I kind of suspect that we would be told to get lost if we requested 256 ASNs from RIPE for traffic engineering our /16 into 256 /24:s... /Bellman