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 two segments to Host B back-to-back. The first and second segments contain 80 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.

3) If the second segment arrives before the first segment, in the acknowledgment of the first arriving segment, what is the acknowledgment number? [3 marks] 4) Suppose the two segments sent by A arrive in order at B. The first acknowledgment is lost and the second acknowledgment arrives 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, write the sequence number and the number of bytes of data and indicate the timeout interval; for each acknowledgment that you add, write the acknowledgment number. [6 marks] 5) Suppose the two segments sent by A arrive in order at B. The first acknowledgment is lost and the second acknowledgment arrives before 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, write the sequence number and the number of bytes of data and indicate the timeout interval; for each acknowledgment that you add, write the acknowledgment number. [4 marks]