Stop and wait in the presence of errors Let p the probability of an error in the transmission of a packet or in its acknowledgment S=Dr+2D。+D TA To the timeout interval X the amount of time that it takes to transmit a packet and receive its acK. This time accounts for retransmissions due to errors E凶]=S+TOP/(1-P), Eficiency=Dp/E凶] Where TO= DTp in a full duplex system To= Sin a half duplex systemStop and wait in the presence of errors Let P = the probability of an error in the transmission of a packet or in its acknowledgment S = DTP + 2D P + DTA TO = the timeout interval X = the amount of time that it takes to transmit a packet and receive its ACK. This time accounts for retransmissions due to errors E[X] = S + TO*P/(1-P), Efficiency = DTP/E[X] Where, TO = DTP in a full duplex system TO = S in a half duplex system