On Thu, 13 Mar 2008, David W. Hankins wrote:
I don't know why Leo thinks so, but even I can observe the "extra recurring support cost of having to work through two stacks with every customer that dials in" as being far greater than any technology costs in either single-stack scenario. The 'recurring' part is the real killer.
If the customer would be v6-only, I agree. If the customer is v4-only, I would posit that it's in most cases impossibleto get the customers upgraded to v6. I would also argue (based on my understanding) that translating or tunneling v4-only clients over v6-only network would cause pretty much equal or greater complexities as dual-stack. If the customer is dual-stack, I would agree that v6-only is simpler, but that gets back to the point of, "does the whole internet support v6 or is there alternative, reliable way to reach the rest?" As a result you will need to deal with v4 connectivity issues as well. NB: we have had dual-stack backbone for about 6 years and are not seeing major pain. Sure, v6-only would be even easier in the longer term, but as far as I've seen, the major transition issues are at the edges, not in the core network. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings