Sequence Numbers WHEN ACKS AND RETRANSMISSION ARE USED, DUPLICATE COPIES OF A MESSAGE MAY BE RECEIVED. THE SENDER CAN'T DISTINGUISH A LOST MESSAGE FROM A LOST ACK. RECEIVER NEEDS TO RECOGNIZE AND DISCARD DUPLICATES. MESSAGES ARE NUMBERED BY SOFTWARE SO DUPLICATES CAN BE IDENTIFIED BY KEEPING LIST OF NUMBERS RECEIVED.

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This page is part of a section of lecture slides related to " Retransmission Techniques " within the topic "Data Delivery Obstacles". Other slides within this section and other sections of slides for the topic "Data Delivery Obstacles" can be accessed using the links below. Retransmission Techniques Acknowledgements and Retransmission Retransmissions and Timeouts Sequence Numbers Sequence Numbers (cont.) Message Reordering Reliability and Connections A Reliable Delivery Problem Cautious Generals Solving the General's Problem Solving the General's Problem (cont.) Connections Establishing Connections Persistent HTTP Connections Network Congestion Packet Loss and Congestion Congestion and Transmission Rate Congestion and TCP Connections Finding the Bottleneck Rate TCP Transmission Rate Adjustment Error Detecting Codes Damagaged Data Symbols and Meaning Interpreting Binary Symbols Evaluating Codes Error Detecting Codes Parity Codes for Error Detection Multiple Bit Errors Interleaved Transmission Error Correcting Codes Any Guesses? Digital Recording on Compact Discs Two-dimensional Parity Bits Spatial Interleaving