Note: soryr for the previous message, I hit the wrong key and sent it by accident Hi Randy,
ok, i give. if ula address space is assigned/managed by registries, how is it actually different from pi space?
Basically ULA space has the same 'routability' as RFC1918 space, with the added benefit of less (or in case of ULA central: no) possibility for conflicting addresses when merging/connecting separate networks. PI space is expected to be routed globally (if the user of the space wants to).
if ipv6 space is effectively infinite (and we once thought ipv4 space was), then what is the use of ula address space? why not just assign vanilla ipv6 space?
At this moment there is no IPv6 PI space (yet) in the RIPE region. When there is PI space, there will maybe be recurring costs for it (RIPE policy proposal 2007-01 is in discussion now). ULA space is free to use and has a low possibility of conflicts, and ULA Central will probably have one-time fee and is globally unique. So the main reason will probably be cost... - Sander