2011_Midterm_1_sol

# B sends 5 acks they are 4 acks with sequence number 2

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Unformatted text preview: sends 5 data segments to Host B, and the 2nd segment (sent from A) is lost. In the end, all 5 data segments have been correctly received by Host B. a. How many segments has Host A sent in total and how many ACKs has Host B sent in total? What are their sequence numbers? Answer this question for all three protocols. b. If the timeout values for all three protocols are much longer than 5 * RTT, then which protocol successfully delivers all five data segments in shortest time interval? Solution: a. GoBackN: A sends 9 segments in total. They are initially sent segments 1, 2, 3, 4, 5 and later re-sent segments 2, 3, 4, and 5. B sends 8 ACKs. They are 4 ACKS with sequence number 1, and 4 ACKS with sequence numbers 2, 3, 4, and 5. Selective Repeat: A sends 6 segments in total. They are initially sent segments 1, 2, 3, 4, 5 and later re-sent segments 2. B sends 5 ACKs. They are 4 ACKS with sequence number 1, 3, 4, 5. And there is one ACK with sequence number 2. TCP: A sends 6 segments in total. They are initially sent segments 1, 2, 3, 4, 5 and later ECE374: First Midterm 5 r...
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## This test prep was uploaded on 03/06/2014 for the course ECE 374 taught by Professor Ganz during the Spring '08 term at UMass (Amherst).

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