Suppose that we attempt to run the sliding window algorithm with SWS = RWS = 3 and with MaxSeqNum = 5. The Nth packet DATA[N]

thus actually contains N mod 5 in its sequence number field.

Give an example in which the algorithm becomes confused; that is, a scenario in which the receiver expects DATA[5] and accepts DATA[0]—which has the same transmitted sequence number—in its stead. No packets may arrive out of order. Note this implies MaxSeqNum ≥ 6 is necessary as well as sufficient.