Advertising IP prefixes to the internet using BGP

Question

I am studying BGP at the moment.

From what I've learned, in order to participate in routing on the internet and use BGP, we need to register a public provider-independent IP address block and a public ASN from one of the RIRs like ARIN (if we exclude private ASNs, of course).

The question is, aren't most of the RIRs already out of IP addresses? If that's the case, how do we get a decent IP block that we can advertise using BGP that would also be provider-independent?

Thank you in advance for your help.

Answer 1

You're only looking at IPv4 I guess, all RIRs have more than enough IPv6 ranges available.

Most RIRs (maybe all by now) don't have any unused IPv4 ranges available anymore. But some do have a waiting list for when ranges become available, for example when a company goes out of business.

And there's always the option of buying or renting IPv4 space from other companies. There's a whole ecosystem dealing with this.

Answer 2

RIRs have long since run out of IPv4 addresses (between 2011 and 2019). You'd need to obtain a (pricey) IPv4 block on the open market.

IPv6 addresses are readily available from the RIRs, of course.