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Sliding Window with cumulative ACK: delayed ACK

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• Sliding Window Example: duplicate (delayed) ACK Error
  • Sliding Window operation when an ACK frame is delayed:

    Sender: Send window = [0, 1, 2] Receiver: Receive window = [0, 1, 2] Example:

    Notes:

    The ACK 1 (for frame 0) is late Sender will retransmit the frame 0 The duplicate data frame 0 is discarded because Receiver window = [1,2,3] Data frame seq no = 0 0 ∉ [1,2,3] !!! So these sliding window will ensure: delivering data frames exactly once !!!