*If* 2004/2005 is a realistic expectation for a full rollout, then *maybe*. The question becomes, is this realistic? I just don't think so.
Judging IP6's current status strictly in light of how far along the large to mid sized providers are, I'd be surprised if a full scale rollout was closer than five years out (which puts us at ~2007). Based on this, and Moore's Law, the BigIron you bought today will be a BigScrapHeap by then anyway.
IPv6 is already heavily deployed here in Japan. here are some numbers I've got: - there are at least 1200 /48 sites in Japan alone http://www.jp.ipv6.org/sitecount/ - there are at least 5 ISPs doing commercial services (you can call up marketing, fill up the form, and you're done) - there are 25+ ISPs doing experimental services Note that the US government required IPv6 in their purchase requirement for DARPA-funded network a couple of months ago. IPv6 will happen, and will deploy rapidly. My take as an operator is, you realliy should start sooner, and act proactively before customers asking for it. We operators need to gather operational experiences much earlier than customers (otherwise we can't make advice to the customers). By the time customers start asking for IPv6, we need a working backbone - we need to be prepared (or you'll lose your potential customer). itojun