Author here. Actually I doubt we'd have picked 27-bit addresses. That's about 134M addresses; that's less than the US population (it's about the number of households today?) and Europe was also relevant when IPv4 was being designed.

In any case, if we had chosen 27-bit addresses, we'd have hit exhaustion just a bit before the big telecom boom that built out most of the internet infrastructure that holds back transition today. Transitioning from 27-bit to I don't know 45-bit or 99-bit or whatever we'd choose next wouldn't be as hard as the IPv6 transition today.

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p_l 5 days ago | parent | next [-]

When 32 bits were chosen it was because it was deemed a temporary thing for an experimental protocol, so there was no need to invest into proposed 128bit addressing by IIRC Vint Cerf (or 160 bit addresses of ITU/ISO protocols).

After all, we were supposed to switch off IPv4 in 1990...

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Ekaros 6 days ago | parent | prev | next [-]

Might have ended up with 27-bit. If you do not really expect personal computer usage and just want to essentially make some proof of concept of interoperability which you will later upgrade or replace.

Maybe there would have been push to change at some point as there would have been real limits in place.

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windward 5 days ago | parent | prev | next [-]

>we'd have hit exhaustion just a bit before the big telecom boom that built out most of the internet infrastructure that holds back transition today

I think this does go both ways. It's hard to care about 3058, but it's nice that we started trying to solve y2k and 2038 while they were still merely painful. Wouldn't want a loop leading to a divide-by-zero in my warp drive.

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cchance 6 days ago | parent | prev | next [-]

why not 10 bit bytes and 40 bit addresses and nice 2 based metric based measures :)

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fc417fc802 6 days ago | parent [-]

If something is painful you aren't doing it often enough, right? So my (completely uninformed) idea would be 27 bit addresses that are only routable on the local LAN and then a second optional 27 bit address to route between LANs on the WAN. The effective 54 bit address space would have been more than large enough, and if you support modularly extending addresses like that then there's no reason not to keep going beyond the initial 2 by eating into the payload.

Being completely uninformed I have no idea how severe the negative consequences of this scheme would be for the efficiency of routing hardware but I assume it would probably be catastrophic for some reason or another.

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MindSpunk 6 days ago | parent [-]

That's very loosely how IPv6 works. Your ISP will typically assign your router a prefix and will route any address starting with that 56 or 64 bit prefix to you. Then devices on your network pick the remaining bits and they get their full address.

	▲	fc417fc802 6 days ago \| parent [-]
		Well IPv4 also used to work that way back before address exhaustion. What I'm describing isn't an arbitrary allocation of a subset of a single fixed bit width address but rather two (or more) entirely disjoint address spaces.

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mrheosuper 6 days ago | parent | prev [-]

Nothing NAT can't solve /s.