How does the TCP protocol confirm the successful receipt of data packets?

The TCP protocol confirms successful data receipt using acknowledgments (ACK). When the receiver gets a data packet, it sends back a special message to the sender — an acknowledgment containing the number of the next expected byte (ACK number). This means that all bytes up to this number have been successfully received.

If the sender does not receive an acknowledgment within a certain time, it retransmits the packet, assuming that the data was lost or corrupted.

Thus, TCP ensures reliable data delivery by using:

• Byte sequence numbering (sequence numbers)
• Acknowledgments (ACK)
• Timeouts and retransmissions

This guarantees that data will reach the receiver without loss and in the correct order.