Why is the maximum ipv4 packet size 65535?

Question

Communication protocols

Why exactly 65535?
If mtu ethernet is usually 1500 so as not to take up a long channel, this is understandable, but why does ipv4 have exactly 65535 and not 1500 like the one in which it is encapsulated or not a different size?

Answer 1

By the fact that only 16 bits are allocated for the packet size. https://en.wikipedia.org/wiki/IPv4
2^16 is about 65k. It is physically impossible to specify a larger packet size.
Well, IP and Ethernet overlap a little. A single IP packet can be carried by multiple Ethernet (or non-ethernet) frames.