How does the TCP/IP Protocol handle error recovery and retransmission of lost packets?

The TCP/IP protocol handles error recovery and retransmission of lost packets through a mechanism called Automatic Repeat Request (ARQ).

When a sender transmits a packet, it assigns a sequence number to it. The receiver acknowledges the receipt of each packet by sending an acknowledgment (ACK) packet back to the sender. If the sender does not receive an ACK within a certain timeout period, it assumes that the packet was lost and retransmits it.

TCP/IP uses a selective repeat ARQ mechanism, where the sender keeps a copy of each transmitted packet until it receives an ACK for that packet. If the sender does not receive an ACK within the timeout period, it retransmits only the lost packet instead of retransmitting all the packets in the window.

To ensure reliable delivery, TCP/IP also implements a sliding window mechanism. The sender can transmit multiple packets without waiting for an ACK for each packet. The receiver maintains a buffer to store out-of-order packets and delivers them to the upper layers in the correct order.

Furthermore, TCP/IP uses checksums to detect errors in the received packets. The receiver calculates the checksum of the received packet and compares it with the checksum value sent by the sender. If there is a mismatch, the receiver discards the packet and requests the sender to retransmit it.

Overall, the TCP/IP protocol provides error recovery and retransmission of lost packets through the use of sequence numbers, acknowledgments, selective repeat ARQ, sliding window mechanism, and checksums. This ensures reliable and accurate data transmission over the network.