> During the days of the IPng directorate, quite a number of different > alternatives were considered. At one point, there was a compromise proposal > known as the "Big 10" design, because it was propounded at the Big Ten > Conference Center near O'Hare. One feature of it was addresses of length 64, > 128, 192, or 256 bits, determined by the high-order two bits. That deal fell > apart for reasons I no longer remember; SIPP was the heir apparent at that > point. Scott and I pushed back, saying that 64 bits was too few to allow for > both growth and for innovative uses of the address. We offered 128 bits as a > compromise; it was accepted, albeit grudgingly. The stateless autoconfig > design came later. > > --Steve Bellovin, http://www.cs.columbia.edu/~smb
This historical record finally made me understand why we have up to /128 prefixes with /128 addresses instead of what would suit best stateless autoconfig: up to /64 prefixes with /128 addresses. Rubens
