James R. Cutler wrote:

Cost of operating v4/v6 combined for some time includes, among other things:

1. Help Desk calls resulting from confused customers wanting configuration help. 2. Memory for Routing Information for IPv4 plus IPv6. 3. Help Desk calls resulting from errors by confused engineers trying to work both protocols on too many devices. 4. Cost of documentation and training for Help Desk personnel. 5. Cost of "Linksys WRT54G-IP6" or equivalent because of increased memory and programming requirements. 6. Cost of software maintenance for network core router software -- didn't we just go through getting rid of DECnet, SNA, IPX/SPX, and AppleTalk because of this, among other reasons?? 7. Marketing cost of being perceived as "obsolete". 8. Opportunity cost due to more complex delivery configurations slowing down sales. 9. Cost of "IP Naming and Addressing Management" due to multiple protocol complexity -- didn't we just go through getting rid of DECnet, SNA, IPX/SPX, and AppleTalk because of this, among other reasons??

Let us not forget that network vendors are now capitalising on the requirement to purchase expensive licensing for such features as native IPv6 routing and 6PE, on their mid to high end kit. I dont feel this sort of behaviour is helpful, I can understand asking for licensing fees for L2VPN/L3VPN technologies since these are products that service providers can levvy a reasonable charge for, but to charge for IPv6 routing capability alone, at the time where the discussion of which has never been so serious, leaves a bit of a bad taste in one's mouth. Dave.