Problem we had in 1995...

IPv6 specification is out, but there's no codebase/testbed

"No codebase" means "high deployment hurdle"
IPv4 was deployed because it was bundled into BSD (and then other operating systems)
BSD served as the reference codebase

With IPv6, only spec is there, almost no code available

We don't really know if the IPv6 spec will work fine or not
Need to check if specification works right, by actual operational experiences

Our answer:
WIDE IPv6 backbone: IPv6 network operation, with real daily traffic
KAME project: IPv6 reference implementation for BSDs
TAHI project: IPv6 conformance/interop testing team
(USAGI project: IPv6 improvements for linux)