Consider a reliable data transfer protocol that uses only negative acknowledg- ments. Suppose the sender sends data only infrequently. Would a NAK-only protocol be preferable to a protocol that uses ACKs? Why? Now suppose the sender has a lot of data to send and the end-to-end connection experiences few losses. In this second case, would a NAK-only protocol be preferable to a protocol that uses ACKs? Why?
If the sender sends the data infrequently (occasionally), then the NAK-only protocol is not preferred. It is good to use the protocol that uses ACKs.
When the sender sends data frequently and the data loss rate is very less, then a NAK-only protocol is preferable to a protocol that uses ACKs.