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Q: How does TCP ensure reliable data transmission?

A: TCP uses several mechanisms to ensure reliable data transmission:

  1. Sequence Numbers and Acknowledgements: Each TCP segment is assigned a sequence number. The receiver sends an ACK (acknowledgement) to confirm receipt. If the sender does not receive an ACK, it retransmits the segment.
  2. Sliding Window: This flow control mechanism prevents the sender from overwhelming the receiver. The receiver advertises a window size, and the sender can only send data up to that limit before receiving an ACK.
  3. Timeout and Retransmission: A timer is set for each sent segment. If an ACK is not received before the timer expires, the sender assumes the segment was lost and retransmits it.
  4. Congestion Control: TCP uses algorithms to detect network congestion and dynamically adjust the sending rate to prevent network collapse.