2 ms·

To illustrate the scale, 2^32: * is roughly equal to 4 300 000 000 (4e9, 4B) * it is also the maximum number of IPv4 addresses Going back to math class: * 2

To illustrate the scale, 2^32: * is roughly equal to 4 300 000 000 (4e9, 4B) * it is also the maximum number of IPv4 addresses Going back to math class: * 2^64 = 2^(32+32) = 2^32 * 2^32 = (4B) * (IPv4 Internet) So a single /64 IPv6 subnet can hold four billion IPv4 Internets worth of systems.

tsimionescu 5y ago
The point was whether 128 bit addresses are actually required - someone was claiming that 64 bit addresses would have also been exhausted, and I pointed out that the current strategy for handing out IPv6 is anyway using up the address space at a similar pace to the situation where we had a 64 bit address and were handing out /64 addresses to individual consumers. There were even some comments claiming certain ISPs are handing out /56 spaces to end consumers.
- throw0101a 5y ago
  Ethernet MACs have 48-bit addresses, and I don't think we've run out of those, and I also don't think is anyone is even worrying about running out of those, so 64-bit IP addresses probably would have been sufficient. But given all the drama with IPv6, I think it was reasonable to go with 128-bit addresses just so we don't have to go through all of this again. On a related note, messing up the assignment of IPv6 address was actually accounted for. If you look at any unicast address that's currently live, you'll see that it begins with a "2". This is because addresses are only being assigned from 2000::/3: * https://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xhtml https://www.iana.org/assignments/ipv6-address-space/ipv6-add... If, for some reason, we realize there's a mistake in how things were done with that space, it will be declared legacy/deprecated, and IANA will start over with addresses from 4000::/3. If that is screwed up, then 6000::/3 will be next, then 8000::/3, a000::/3, and finally c000::/3. So the Internet community has six tries to get IPv6 addressing correct.
  - deleted 5y ago
    [deleted]

tsimionescu 5y ago

The point was whether 128 bit addresses are actually required - someone was claiming that 64 bit addresses would have also been exhausted, and I pointed out that the current strategy for handing out IPv6 is anyway using up the address space at a similar pace to the situation where we had a 64 bit address and were handing out /64 addresses to individual consumers. There were even some comments claiming certain ISPs are handing out /56 spaces to end consumers.

throw0101a 5y ago
Ethernet MACs have 48-bit addresses, and I don't think we've run out of those, and I also don't think is anyone is even worrying about running out of those, so 64-bit IP addresses probably would have been sufficient. But given all the drama with IPv6, I think it was reasonable to go with 128-bit addresses just so we don't have to go through all of this again. On a related note, messing up the assignment of IPv6 address was actually accounted for. If you look at any unicast address that's currently live, you'll see that it begins with a "2". This is because addresses are only being assigned from 2000::/3: * https://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xhtml https://www.iana.org/assignments/ipv6-address-space/ipv6-add... If, for some reason, we realize there's a mistake in how things were done with that space, it will be declared legacy/deprecated, and IANA will start over with addresses from 4000::/3. If that is screwed up, then 6000::/3 will be next, then 8000::/3, a000::/3, and finally c000::/3. So the Internet community has six tries to get IPv6 addressing correct.
- deleted 5y ago
  [deleted]