[dangerlibrary]

> Without IPv6 network sees an unsupported IPv4 packet and throws it away. You need something to convert IPv4 to IPv6.

Acknowledging my own ignorance here, assuming this sentence seemingly disregards my point, because this was a choice. The IPv6 standard chose to fix the header length at 40 bytes and operate differently from IPv4, but the standard could easily have said "We're re-using the IPv4 header format, except now addresses are variable-length up to 128 bits."

[Ekaros]

Because they also noticed that IPv4 has some design errors. So if you are anyway making something incompatible you can fix those and bring in new features.

IP packet having checksum that is also calculated on the hops remaining. Well, do you really really need that when most popular protocols TCP and UDP have also a checksum? So getting rid of it entirely is actually a smart move.

And then whole ARP, DHCP etc. Can we do something more sensible instead of that sort of thing. Different mindset, but reasonable attempt.