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Many reasons why 128-bit addresses are great: - No more tradeoff between number of networks vs hosts, vastly simplifying planning in large networks. (/64 subne

by zeroxfe 11y ago

Many reasons why 128-bit addresses are great: - No more tradeoff between number of networks vs hosts, vastly simplifying planning in large networks. (/64 subnets gives you 10^19 networks each with effectively an infinite number of hosts.) - Security/privacy. Try port-scanning a /64 subnet -- let me know when you're done. (BTW, that was just one network.) - Host addresses can be encoded in the lower 64 bits, which allows for all kinds of efficiencies, like stateless autoconfiguration. - ULA, which allows you to reserve a site-local (non-Internet-routable) address space, without an external registry, and with very high probability of global uniqueness. (Remember the time your company acquired that other company, and had to merge their 10.0.0.0/8 with yours?) - Global unicast is a /3, which means if we screwed something up, we still have 7 more attempts (each with 10^37 addresses.) The thing with having more bits is that it allows you to do more interesting things, without the pressures of scarcity.

ploxiln 11y ago
Limitations are good. See the currently highly-rated top-level comment: "why can't every server get a /48 so I can perpetrate the most ridiculous waste of address space imaginable?" The idea of 128-bit address space seems to be that people can waste it like crazy and there will still be plenty for centuries to come. But that underestimates people's ingenuity in coming up with nifty things they could do if they wasted even more address space, and with no obvious reason not to they'll do it, until we're back in the same situation. Really, one day people will be wanting a /32 so they can do something nifty, and then it'll become a common thing, and the situation will seem oddly familiar... 10 years ago I played graphically rich instant-response video games on a desktop computer with 512mb ram and 128mb video ram (and fairly powerful cpu and gpu for the time). I knew that in the coming years more memory and processing power would enable ever more detailed visuals. But I didn't know that I would use significantly more system and gpu memory than that, just to read email in a browser tab. Because why not I guess...
ChuckMcM 11y ago
You forgot the one where you could use them as two 9bit/55bit fixed point numbers representing latitude and longitude and have your IP address identify where you are to within a couple of microns :-). And computers have gotten so fast and memory so large and storage so cheap that nobody cares. I get it. During the IPV6 discussions at IETF people kept saying "but 64 bits is just twice as big as our current space, we'll run out in no time" and I kept saying "No its 4 billion times bigger". It is water under the bridge. At some point I'm going to sit down and reason out the cost of 128 versus 64 bits (which is the inverse of 'why they are great' but more 'why they aren't great') but since I never expect that I'll get a chance to design network protocols at that level again its really just a hobby for me.
- gonzo 11y ago
  > and have your IP address identify where you are to within a couple of microns Well, on Earth, yeah. But not in space.

by zeroxfe 11y ago

ploxiln 11y ago

Limitations are good. See the currently highly-rated top-level comment: "why can't every server get a /48 so I can perpetrate the most ridiculous waste of address space imaginable?" The idea of 128-bit address space seems to be that people can waste it like crazy and there will still be plenty for centuries to come. But that underestimates people's ingenuity in coming up with nifty things they could do if they wasted even more address space, and with no obvious reason not to they'll do it, until we're back in the same situation. Really, one day people will be wanting a /32 so they can do something nifty, and then it'll become a common thing, and the situation will seem oddly familiar... 10 years ago I played graphically rich instant-response video games on a desktop computer with 512mb ram and 128mb video ram (and fairly powerful cpu and gpu for the time). I knew that in the coming years more memory and processing power would enable ever more detailed visuals. But I didn't know that I would use significantly more system and gpu memory than that, just to read email in a browser tab. Because why not I guess...

ChuckMcM 11y ago

You forgot the one where you could use them as two 9bit/55bit fixed point numbers representing latitude and longitude and have your IP address identify where you are to within a couple of microns :-). And computers have gotten so fast and memory so large and storage so cheap that nobody cares. I get it. During the IPV6 discussions at IETF people kept saying "but 64 bits is just twice as big as our current space, we'll run out in no time" and I kept saying "No its 4 billion times bigger". It is water under the bridge. At some point I'm going to sit down and reason out the cost of 128 versus 64 bits (which is the inverse of 'why they are great' but more 'why they aren't great') but since I never expect that I'll get a chance to design network protocols at that level again its really just a hobby for me.

gonzo 11y ago
> and have your IP address identify where you are to within a couple of microns Well, on Earth, yeah. But not in space.