Computer Networks

Hosts A and B are communicating over a TCP connection. Host B has already received from A all bytes up through byte 153 and A has received an ACK for all these bytes. Suppose Host A then sends three segments to Host B back-to-back. The first, second and third segments contain 60, 40, and 80 bytes of data respectively. In the first segment, the source port number is 503, 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 are the sequence number, source port number, and destination port number? b If the first segment arrives before the second and third segments, in the acknowledgement of the first arriving segment, what is the acknowledgement number, the source port number, and the destination port number? c If the third segment arrives before the first and second segments, in the acknowledgement of the first arriving segment, what is the acknowledgement number? d Suppose the three segments sent by A arrive in order at B. The first acknowledgement is lost and the second and third acknowledgements arrive after the first timeout interval. Draw a timing diagram, showing these segments and all other segments and acknowledgements 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 acknowledgement that you add, provide the acknowledgement number