1. Textbook (8th edition) problem 3 (page.287) (25 points, 5 points for each subproblem)

P3. UDP and TCP use 1s complement for their checksums. Suppose you have

the following three 8-bit bytes: 01010011, 01100110, 01110100. What is the

Is 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. Why is it that UDP takes

the Is complement of the sum; that is, why not just use the sum? With the Is

complement scheme, how does the receiver detect errors? Is it possible that a

1-bit error will go undetected? How about a 2-bit error?