Patrick W. Gilmore wrote:
On Feb 4, 2009, at 6:56 PM, Scott Howard wrote:
On Mon, Feb 2, 2009 at 9:35 PM, Patrick W. Gilmore <patrick@ianai.net>wrote:
Except the RIRs won't give you another /48 when you have only used one trillion IP addresses.
Of course they will! A /48 is only the equivalent of 65536 "networks" (each network being a /64). Presuming that ISPs allocate /64 networks to each connected subscriber, then a /48 is only 65k subscribers, or say around a maximum of 200k IP addresses in use at any one time (presuming no NAT and an average of 3-4 IP-based devices per subscriber)
IPv4-style utilization ratios do make some sense under IPv6, but not at the address level - only at the network level.
First, it was (mostly) a joke.
Second, where did you get 4 users per /64? Are you planning to hand each cable modem a /64?
That was the generally accepted subnet practice last time I had a discussion about it on the ipv6-ops list. I'm not an ISP, but I have a /48 and each subnet is a /64. Some devices will refuse to work if you subnet smaller than a /64. (Yes, poorly designed, etc.) ~Seth