3. [Points: 3X1, 2] 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 is 302, and the destination port number is 80. Host B sends an acknowledgement whenever it receives a segment from Host A. (a) In the second segment sent from Host A to B, what is the sequence number, source port number, and destination port number? (b) If the first segment arrives before the second segment, in the acknowledgement of the first arriving segment, what is the acknowledgement number, the source port number, and destination port number? (c) If the second segment arrives before the first segment, in the acknowledgement of the first arriving segment, what is the acknowledgement number? (d) Suppose the two segments sent by A arrive in order at B. The first acknowledgement is lost and the second acknowledgement arrives after the first time-out interval. Draw a timing diagram, showing these segments and all other segments and acknowledgements 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 acknowledgement that you add, provide the acknowledgement number