Host A and B are communicating over a TCP connection, and Host B has already received from A all bytes up throught byte 126. Suppose Host A then sends two segments to Host B back-to-back.

The first and second segments contain 80 and 40 bytes of datam 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 aknowledgment whenever it receives a segment from Host A.

a. In the second segment sent from Host A to B, what are the sequence number, source port number, and destination port number?

b. If the first segment arrives before the second segment, in the aknowlegment, of the first arriving segment, what is the aknowledgment number, the source port number, and the destination port number?

c. If the second segment arrives before the first segment, in the aknowledgment of the first arriving segment, what is the aknowledgment number?

d. Suppose the two segments sent by A arrive in order at B. The first aknowledgment is lost and the second aknowledgment arrives after the first timeout interval.

Draw a timing diagram, showing these segments and all other segment and aknowledgements sent. ( Assuming 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 aknowledement that you add, provide the aknowledgment number.

Text book-----Jim Kurose and Keith Ross,"Computer Networking - A Top-Down Approach", Addison-Wesley, Seventh Edition, 2017. ISBN-13: 978-0-13-359414-0