Consider a transport protocol over a wide-area network. The protocol uses an error control scheme where every ACK (acknowledgment) carries the sequence number of the last in-sequence packet seen by the receiver (also called the cumulative acknowledgment).
(a) How can a sender use repeated (duplicate) ACKs to improve its detection of packet loss? Would you use a different number of repeated ACKs depending on whether the network is connectionless or connection-oriented? Explain.
(b) An extension to the basic scheme in part (a) is for each ACK from a receiver to carry, in addition to the cumulative acknowledgment, the sequence number of the packet that caused the ACK to be sent. Under this scheme, what do ACKs contain when a receiver receives packets with sequence numbers 5, 7, 8, 10? What should the sender do upon the receipt of each ACK? Does the additional information carried in each ACK help improve performance? If so, explain why