Michael, Michael.Dillon@btradianz.com wrote:
/64 was for stateless autoconfig (EUI-64). /48 was to make it easier for folks to move between ISPs. Since all allocations to end sites would be the same size, all that would need to change would be the upper 48 bits.
In particular, this means that moving between ISPs does not require you to change your internal network topology. Since topology changes can involve a lot of equipment purchase and rewiring, this levels the competitive field for IPv6 access services. You can design your network with the future in mind and then grow into your topology. That is not possible in today's IPv4 world where everybody is concerned with not wasting addresses.
I think it's worth clarifying that RIPE's IPv4 policy specifically states that one-to-one renumbering for valid assignments are fine. The relevant text can be found at: http://www.ripe.net/ripe/docs/ipv4-policies.html#assign_renumbering Individual ISPs may choose to be assign addresses in a more conservative way than is strictly required. Regards, -- leo vegoda Registration Services Manager RIPE NCC