How does the TCP protocol ensure reliable data delivery between two devices?

TCP (Transmission Control Protocol) ensures reliable data delivery through several key mechanisms:

• Connection establishment (handshake): a three-way handshake (SYN, SYN-ACK, ACK) occurs before data transfer, guaranteeing both parties are ready.
• Segment numbering: each byte of data is numbered, allowing tracking of order and loss.
• Acknowledgments (ACK): the receiver sends acknowledgments upon receiving data; the sender retransmits data if acknowledgment is not received.
• Flow control: a sliding window mechanism regulates the transmission rate to prevent overwhelming the receiver.
• Error checking: a checksum is used to verify data integrity.

Example: if a data packet is lost in the network, the sender will not receive an acknowledgment and will resend the data, thus ensuring reliability.