UNIVERSITY OF CALIFORNIA, DAVIS
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BERKELEY
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DAVIS
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IRVINE
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LOS ANGELES
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RIVERSIDE
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SAN DIEGO
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SAN FRANCISCO
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SANTA BARBARA
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SANTA CRUZ
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EEC 173A/ECS 152A-Computer Networks
Spring 2018
Homework #3 (due May 7, 2018)
Total: 100 points
1.(10 points)Stop-and-wait.(a)(4 pt.) What is the main short-coming of the stop-and-wait algorithm for error recovery? (b)(6 pt.) Given a 1.5 Mbps (Megabits per second) link with a 30 usec (microseconds) round-trip delay. With a frame size of 1KB (KiloBytes), what is the link utilization using the stop-and-wait algorithm? For simplicity, you can assume the acknowledgement packet is of negligible size, i.e., size 0. 2.(30 points)Performance of Stop & Wait, Go-Back-N, and Selective Repeat. Suppose the bandwidth on a point-to-point link to moon is 1 Mbps and the one-way propagation delay is 1 second. Assume that size of each packet is 125 bytes. Answer the following for each ARQ scheme: stop-and-wait, go-back-n and selective-repeat? (a)(9 pt.) Assuming that the link is error-free, what is maximum rate of transmission achievable from earth to moon? (Assume zero queuing delay, and assume zero transmission time for ACK packets). (b)(3 pt.) Assuming that the link is error-free, to keep the pipe full for efficiency, what should be
