*> *> My point remains, a globally meaningful address is something that *> should only be applied when it is useful for that endpoint to *> be globally addressable. *>
That sounds like an appealing statement, but it hides the potential cost of giving up generality. Back when TCP/IP was young, the operating systems researchers in Computer Science departments had just found a new playpen -- distributed operating systems. They disdained TCP/IP, choosing to implement their OS mechanisms on "bare" Ethernets. Their statement was that a globally meaningful protocol is something that should be applied only when it is useful for the endpoints to be globally reachable. Since all their boxes were local, and for efficiency, they insisted on running directly over the link layer. (And BTW, there was only one link layer, Ethernet ;-)) We told them that the day would come when they would want the general connectivity of IP, but they were, as I said, disdainful. It took a few years for them the realize the error of their approach, but they did eventually. So there is a trade-off here. In general, I think one can say that the Internet has benefited hugely in the past from taking the approach of maximum flexibility whenever feasible. Bob Braden
