Host A and B are communicating over a TCP connection, and Host B has

already received from A all bytes up through byte $126.$ Suppose Host A then sends three

segments to Host B back$-$to$-$back. The first, second and third segments contain $80,60,$ and $40$

bytes of data, respectively. In the first segment, the sequence number is $127,$ the source port

number is $302,$ and the destination port number is $80.$ Host B sends an acknowledgment

whenever it receives a segment from Host A$.$

a$.$ In the second and third segments sent from Host A to B$,$ what are the sequence

number, source port number, and destination port number for each of the segments?

b$.$ Assume all segments from A arrive B in order and correct. Assuming Host B sends

an acknowledgment whenever it receives a segment from Host A$,$ what is the

acknowledgment number, the source port number, and the destination port number of

each of the three acknowledgments sent from B to A$.$

c$.$ Assume that the first segment arrives, then the third segment, then the second

segment. What is the acknowledgment number, the source port number, and the

destination port number of each of the three acknowledgments sent from B to A$.$

d$.$ Assume that the second segment arrives first, then the first segment, then the third

segment. What is the acknowledgment number, the source port number, and the

destination port number of each of the three acknowledgments sent from B to A$.$

e$.$ Assume that the third segment arrives first, then the first segment, then the second

segment. What is the acknowledgment number, the source port number, and the

destination port number of each of the three acknowledgments sent from B to A$.$

f$.$ Suppose the three segments sent by A arrive in order at B$.$ The first acknowledgment

is lost and the second and third acknowledgments arrive after the first timeout

interval. Draw a timing diagram, showing these segments and all other segments and

acknowledgments sent. $($Assume there is no additional packet loss.$)$ For each segment

in your figure, provide the sequence number and the number of bytes of data; for each

acknowledgment that you add, provide the acknowledgment number.