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诚信应考,考试作弊将带来严重后果！ 华南理工大学期末考试 《 Computer Networks 》A试卷 注意事项：1. 考前请将密封线内填写清楚； 2. 所有答案请直接答在试卷上(注：选择题答案请填入题目前面的表格中)； 3．考试形式：闭卷； 4. 本试卷共五大题，满分100分, 考试时间120分钟。 题 号 1 2 3 4 5 总分 得 分 评卷人 1. Select the correct choice. (30 scores, every one is 2 scores) NO. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 solution (1) It is the architecture for TCP/IP protocol stack, which one below doesn’t belong to the application layer ( )? A. TELNET　 B.ICMP　　C. POP　　D. SMTP (2) Why do HTTP, FTP, SMTP and POP3 run on top of TCP rather than UDP? ( ) A. Reliable data transfer B. Throughput C. Real-time D. Security (3) Suppose Host A wants to send a file to Host B, there are three links between A to B, and the rates of the three links are respectively R1=2 Mbps, R2= 1Mbps, and R3= 4 Mbps. If no any other traffic in the network, what is the throughput for the file transfer? ( ) A. 2 Mbps B. 1 Mbps C. 4 Mbps D. 7Mbps (4) Suppose an application generates chunks of 120 bytes of data every second, and each chunk gets encapsulated in a TCP segment and then an IP datagram(no options fields).What percentage of each datagram will contain application data? ( ) A. 80% B. 75% C. 60% D.25% (5) The job of delivering the data in a transport-layer segment to the correct socket is called ( ). A. Demultiplexing B. Multiplexing C. TDM D. FDM (6) Consider sending a 999 byte datagram into a link that has an MTU of 500 bytes , ( ) A. 2 fragments are created with offset field value 0,500, respectively B. 3 fragments are created with offset field value 0, 480, 960, respectively C. 3 fragments are created with offset field value 0, 60, 120, respectively D. None of these above (7) About the encapsulation relationships of segment、datagram and frame, which of the following is correct? ( ) A. Segment is encapsulated within the frame, and the frame is encapsulated within the datagram. B. Datagram