On Thu, 21 Oct 2010 19:21:41 PDT, George Bonser said:
With v6, while changing prefixes is easy for some gear, other gear is not so easy. If you number your entire network in Provider A's space, you might have more trouble renumbering into Provider B's space because now you have to change your DHCP ranges, probably visit printers, fax machines, wireless gateways, etc. and renumber those, etc. And some production boxes that you might have in the office data center are probably best left at a static IP address, particularly if they are fronted by a load balancer where their IP is manually configured.
"If Woody had gone straight to a ULA prefix, this would never have happened..." If a site is numbering their internal IPv4 stuff to avoid having to renumber on a provider change, then why would they number their IPv6 stuff from provider space rather than ULA space? And remember - (a) IPv6 allows machine to easily support multiple addresses and (b) if you have a provider address and a ULA, changing providers only means renumbering a *partial* renumber of the hosts that require external visibility - your internal hosts can continue talking to each other on a ULA as if nothing happened. Sure beats the mayhem if your company buys an organization and the 1918 spaces the 2 groups use overlap... Yee-hah. ;)