[KomoD]

> could probably have been made smaller

A lot of reserved ranges could've been made smaller, 127.0.0.0/8 is JUST loopback, that's over 16 million ips just for loopback! 0.0.0.0/8 is also just absurd

224.0.0.0/4 and 240.0.0.0/4 are also crazy... over 500 million ips.

I probably wouldn't care about it if we didn't have ipv4 exhaustion (which is in my opinion is at least partially the US govt's fault, because they're hoarding 200+ million ips)

[kaliszad]

More than 40 years later it can seem so. But with these you were basically able to just check the first byte, perhaps it was an optimization of some sort. Reserving ~1/8 of the available address space for other use cases or future needs is reasonable and not out of line. The ASCII encoding also uses just 7/8 of a byte to encode letters and thanks to this we were able to make UTF-8 compatible enough. IPv4 could have been 48 bit just like the MAC and we wouldn't have this conversation. Nowadays a /48 prefix (in IPv6) is basically the smallest we hand out.

Of course, we could've used /80 as the smallest possible prefix for auto-negotiation, leaving more room for playing with prefixes but it is what it is. Nobody sane will wait another 20-25 years before any kind of change is widespread in all the stacks. Even less people will care about the reserved/multicast space, 0/32 or 127.0.0.0/24 because it is so much work for little benefit as it will never be supported by all the legacy systems that care about IPv4 since for them there is no IPv6. We should all concentrate on IPv6 and get on with the colossal migration. Even HN supports IPv6 as of this year!