On Sat, 17 Jan 2004, Keith Moore wrote: > > The residential users don't need to have a globaly unique IP address. > > That's like saying residential telephone users don't need to have a > phone number at which they can be reached. (after all, the purpose of > their residential phones is to call businesses for the purpose of > obtaining services, right?) No, its not at all like saying that. Its like saying that residential phone users don't need a globally unique circuit facilities assignment (CFA) number. Indeed, most residential telephone users aren't aware of that number, even though they have one. The globably unique telephone number is more comparable to the email address, or the instant message id. I contact you at moore@xxxxxxxxxx, not your IP address. And when I call your phone number, computers (telephone switches) figure out the physical switch port number to route the call to. I don't need to know that number; That number doesn't need to be unique. Indeed, its quite possible that your phone number might even replace your email address as your globally unique identifier. And thus it might not matter whether IP is even used at all. One could connect to that phone number via TDM switched circuits, via Voice over IP, via Voice over Frame Relay, or via some other yet-to-be-invented method. That connection could be voice, email, instant messaging, web, etc. I don't want to go into the merits of this, but only to use this as an example that IP addresses don't necessarilly need to be globally unique, so long as there exists other globably unique identifiers and gateways between different kinds of networks. > There are lots of apps that would be valuable to residential users if > residential users had reachable IP addresses. check the status of your > alarm system, or your roast in the oven, or your freezer's inventory. > Grab a picture from your baby-cam while you're out for dinner and have > left the kid with the baby sitter. Reset the thermostat if you're > going to be out of town longer than you thought. Do all of these from > your portable phone/PDA which is running guess what? -- IPv6. Sure, but these are servers; servers that many residential use contracts prohibit except at additional cost. And like email, such services can be implemented without static ip addresses by 'pushing' data up to a web or application server. Certainly, IPv6 could enable some things that aren't possible without it, and could provide more implementation and design choices to the application developers. I don't dispute that. But this is not free. There are practical costs associated with this. > IPv6 will eventually replace IPv4, but it's misleading to think of IPv6 > as just a replacement for IPv4. By the time IPv6 replaces IPv4, we > won't recognize the IPv6 network as something that resembles what the > IPv4 network is used for today. Even though the underlying technology > is very similar, IPv6 is really a new kind of network, one that enables > things that were really never possible with IPv4 on a large scale. I agree. But like Cobol, technically better solutions aren't always adopted, and even when they are adopted, the inferior solutions often don't go away for a long time. --Dean