-----Original Message----- From: Tim Durack [mailto:tdurack@gmail.com] Sent: Monday, January 25, 2010 14:03 To: TJ Cc: nanog@nanog.org Subject: Re: Using /126 for IPv6 router links
<<snip>>
2^128 is a "very big number." However, from a network engineering perspective, IPv6 is really only 64bits of network address space. 2^64 is still a "very big number."
An end-user assignment /48 is really only 2^16 networks. That's not very big once you start planning a human-friendly repeatable number plan.
An ISP allocation is /32, which is only 2^16 /48s. Again, not that big.
Once you start planning a practical address plan, IPv6 isn't as big as everybody keeps saying...
I didn't realize "human friendly" was even a nominal design consideration, especially as different humans have different tolerances for defining "friendly" :) I (continue to) maintain that: *) 2^16 is still a pretty good size number, even allowing for aggregation / summarization. *) If you are large enough that this isn't true - you should (have) request(ed) more, naturally - each bit doubles your space ... /TJ