Network does have a natural order. You can make a routing decision faster when you get the most significant units first. If you get the least first, you have to wait for the entire address before you can route to it.

Oh cool - I never knew this was the reason why...

Thanks!

This is mostly irrelevant today though; the hardware is so much faster and memory so much more plentiful that handling is done by reading the full header (and often full packet) then making the routing or forwarding decision. You don't need to squeeze out every single cycle or save every single byte possible. You have so much headroom saving cycles or bytes makes no difference and you can't optimize enough to make significant BOM reductions by choosing cheaper chips while still offering features considered standard. Even if you could you'd be selling into an ultra-ultra-cheap market segment no one cares about (congrats, you made a $2 10Mbps router that can run on a coin cell battery).

That something doesn't make a big improvement doesn't mean that the improvement does not exist.

If I wanted to show where ordering truly does not matter, I would rather look at encoding schemes. Some versions of Ethernet use https://en.wikipedia.org/wiki/64b/66b_encoding , meaning that the smallest unit that can be read at once is 8 bytes. That removes the ordering from IPv4 addresses, but IPv6 can still get handled earlier by taking ordering into account.

Huh - I would have thought for higher speed stuff (say 40G+ ?) performance would still be an issue if you wanted to maintain wire speed - Especially driving multiple interfaces ?

I agree home/consumer stuff is just basicly coasting on 3-4 generation tech though. I ran cat-6 cable around the house hoping to get 10G sometime in my lifetime for less then the cost of a kidney...

>>Network has no natural order

"When the bytes which make up such multi-byte numbers are ordered from most significant byte to least significant byte, that is called "network byte order" or "big endian." (1)

Seems pretty straightforward MSB to LSB? which is what I learned way back in 'C' times...Did something change ?

1) https://datatracker.ietf.org/doc/html/draft-newman-network-b...