3 ms·
The RIPE guidelines at [0] line up with what I've heard as justification before: basically, /64 is the smallest you can go without lots of manual configuration
by cfallin 7y ago
The RIPE guidelines at [0] line up with what I've heard as justification before: basically, /64 is the smallest you can go without lots of manual configuration (the way that SLAAC auto-assigns addresses from Ethernet MACs or random bytes only works when the host part of the address is 64 bits). There may be valid technical reasons to want > 1 subnet at a customer site.
And finally, the space is huge -- an ISP would typically get a /32 at least (Whois says that Comcast is using a /26 just for the Bay area), so if every customer gets a /60, that's 2^28, or 256M, delegations. (With the /26, Comcast could hand out 16 billion /60 delegations to their SFBA subscribers.)
[0] https://www.ripe.net/publications/docs/ripe-690#4--size-of-end-user-prefix-assignment---48---56-or-something-else- https://www.ripe.net/publications/docs/ripe-690#4--size-of-e...