Suppose Host A sends three TCP segments back to back to Host B over a TCP connection. The amounts of data in these three segments are 100B, 10B, and 50B from the first to the third segment respectively. Assume that the first segment’s sequence number (i. e., the sequence number of the first byte in the first segment) is 20. Suppose the second segment is lost but the other two segments arrive at B. Further assume that ACKs arrive safely back to A.
a. What are the sequence numbers of the second and the third segments?
b. What will be the ACK numbers that Host B sends to Host A?
c. Suppose the TCP reliability algorithm is using selective acknowledgments (i. e. TCP SACK). What will be the ACK (or NACK) numbers that Host B sends to Host A? Briefly explain.