Book: Computer Networking A Top Down Approach

Chapter 3 EQ2:

UDP and TCP use 1s complement for their checksums. Suppose you have the following three 8- bit bytes: 01010111, 01110110, 01110101.

(a) What is the 1s complement of the sum of these 8-bit bytes? (Note that although UDP and TCP use 16-bit words in computing the checksum, for this problem you are being asked to consider 8-bit sums.) Show all work.

(b) With the 1s complement scheme, how does the receiver detect errors?

(c) Is it possible that a 1-bit error will go undetected? How about a 2-bit error?

Please Show Clear Work and Explanation!