It goes without saying that all binary network protocols should document their byte order, and that if you're implementing a protocol documented as big endian you should use ntohl and friends to ensure correctness.

However if designing a new network protocol, choosing big endian is insanity. Use little endian, skip the macros, and just add

Assuming an 8-bit byte used to be a "vendor specific hack." Assuming twos complement integers used to be a "vendor specific hack." When all the 36-bit machines died, and all the one's complement machines died, we got over it.

That's where big endian is now. All the BE architectures are dying or dead. No big endian system will ever be popular again. It's time for big endian to be consigned to the dustbin of history.