Robin,
IPv6 has been available in operating systems for at least 10 years, but in terms of adoption, it has been a spectacular failure. This long-standing pattern of lack of interest among end-users would have to be dramatically changed if IPv6 was to make the IPv4 routing scaling problem no longer a concern.
I have heard this many times before, and I would caution you, Robin, and this group to not go there for several reasons:
1. There is no serious Plan B. Any plan that came to be today likely couldn't be fielded. 2. Sometimes technologies arise before their time. This was certainly the case, for instance, with X.509, which was adopted by the ITU in 1988, and didn't see widescale deployment afterwards for nearly six years for a use that was not particularly envisioned by its creators. 3. This is really not all that germane to architectural discussions. The problems we are discussing will be present in any version of IP or anything else that has encoded hierarchy in their addresses and demands multiple presences in a network topology.
Eliot -- to unsubscribe send a message to rrg-request@psg.com with the word 'unsubscribe' in a single line as the message text body. archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg