Hello, Ray, 2012-12-19 09:57, Ray Hunter <[email protected]> : ... > It seems to me with the benefit of hindsight that a fundamentally better > approach would have been to reserve many more bits in the IID, or in RA > PIO, to create mutually exclusive subspaces per assignment mechanism or > per class of assignment mechanism, but that train has probably left the > station long ago, and that now assigning a huge block of space for u=1 > g=1 exclusively for a tunnel protocol like 4rd is fundamentally unfair > and restrictive for future assignment mechanisms.
The proposal is precisely to use the only remaining unused pattern (u=g=1) as an escape mechanism FOR ALL future IID formats. (Among IIDs having u=g=1, 4rd is proposed to reserve only IIDs starting with 00000011, i.e. 1/64th of the left space.) In my understanding, this exactly what you are looking for in view of constraints of compatibility with past decisions. Note that, with the 4rd specification as is, the 4rd reserved pattern could even be 0000001100000000, i.e. 1/16384 of the left space. Hoping it clarifies, Regards, RD -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
