One padding instead of the sum of bits

Question

The question in my homework at the university is why use one addition instead of the sum of bits in the TCP checksum. I can not find it in my book, and Google does not help. Any chance anyone can point me in the right direction?

Thanks Mike

Answer 1

Since this is a homework question, here is a tip:

Suppose you calculated the second checksum for the entire package, including the first checksum? Is there a mathematical expression that defines the result?

Answer 2

Probably the most important thing is that it does not depend on the end.

Endian LSB (, Intel). Endian LSB (, IBM). LSB 1 ), , 03 + 01 01 + 03: .

, , IP.

: http://www.netfor2.com/checksum.html