# EE444HW5 - LAN has total 8 stations(including A and B and a...

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EE 444 INTRODUCTION TO COMPUTER NETWORKS Spring 2009 HOMEWORK # 5 Deadline: May 8 2009 @ 23:59 (No late submission is allowed.) Posted on May 1 2009. Question # 1 The round-trip propagation delay for a 10Mbps link is 200msec. Total probability of error (probability that a data frame or an acknowledgement frame is in error) is 0.2. Assume that frame size is 1Kbits and acknowledgement and headers are negligible. (a) Which data link layer protocol would you use to maximize the efficiency? Specify its parameters if possible. Briefly explain your reasoning. (b) At least how many bits are required for the sequence number when the maximum data rate is achieved? (c) What is the maximum data rate? Clearly state any reasonable assumption you make, and explain your reasoning. Question # 2 Consider the network configuration in the following figure. The application running on Host A is sending data to Host B through a LAN and ACK frames from station B are sent over the point-to-point link. The
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Unformatted text preview: LAN has total 8 stations (including A and B) and a bandwidth of 1 Mbits/s. The MAC protocol running on the LAN is CSMA/CD. Hosts A and B are located at the farthest two points in the LAN with the one way propagation delay of 0.5 msec. The propagation delay on the point to point link from B to A is 0.2 msec. A and B use Selective Repeat (with 4 bit sequence numbers). The data link layer frames are 1.4Kbits long. The probability that the medium is successfully captured by any station is observed to be 0.385. What is the average bandwidth available to the network layer for this communication? Assume that there are no bit errors. Ignore all headers and size of ACK frames. Clearly state any reasonable assumption you make, and explain your reasoning. CSMA-CD LAN A B Point to point link from B to A...
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