Go-Back-N and Selective Repeat are two data transmission protocols. Go-Back-N allows the sender to transmit multiple packets before receiving ACKs, but retransmits all packets after the lost packet when an error occurs. Selective Repeat retransmits only the packet with errors, avoiding unnecessary retransmissions. It uses buffers to store packets for potential retransmission, handling errors more efficiently than Go-Back-N when delays or data rates are high.