I don't know what will be said but I've wondered why they went to 128 bit addresses when 64 should have been "enough for anybody." Note 64 bit isn't double 32, but rather like 4 billion times more if my math isn't too far off.
Imagine having to type those addresses out by hand. Though skipped 0 are allowed, hex only helps a little. Not looking forward to that.
Back when IPv4 was put in place, they had no idea the net would become so important. Now they know, and so going all the way to 128 helps futureproof.
Also, look at the (though media over-hyped) Y2K thing. that was a case of "good enough" that ended up staying in production way beyond expectation.
Heck, there are companies out there selling devices that allow "old" industrial looms to load patterns from SD cards and such when they were originally designed to take floppies. This via a device that have a floppy cable connector at one end, a SD slot at the other, and fix inside a 5.25" or 3.5" drive bay.
Computational stuff seems to stay in use way longer than anyone imagined back when every year or so seemed to produce whole new architectures.
Right, futureproofing. But this is not like when hard disks were 512mb, then 2gb, then 4, and kept hitting very shortsighted limits.
We're surviving now with only minor discomfort on a 32 bit address space, and 64 is billions of times more space.
128 is just showing off for no obvious reason that I can see, besides looking like guids. The number approaches the number of atoms in the universe I believe. I'm guessing a universe-wide addressing system can wait a few years, haha.
There are 64 bits for the network prefix, and then 64 bits for devices on the network.
So you'll have a network like 2001:f4dc:2110::/64, and then you can allocate ::1, ::2, ::3. Real had to allocate by hand, right? Not really. Sure, billions of addresses go unused, but who cares? With expansion it's fine - you just write 2001:f4dc:2110::2.
If you had to write 2001:f4dc:2110:0000:0000:0000:0000:0002 then I would sympathise. But you don't.
The second 64 bits are reserved for future innovation. Ethernet nodes happen to populate it with tedious junk, but that forces ISPs to allocate a /64 per user as a bare minimum.
Over the coming years and decades, people will repurpose those bits to do interesting stuff at the network edge, without forklifting the entire Internet again.
Imagine having to type those addresses out by hand. Though skipped 0 are allowed, hex only helps a little. Not looking forward to that.