云南大学软件学院计算机网络原理期中试卷王世普

云南大学2015至2016学年上学期软件学院2014级

《计算机网络原理》期中考试试卷(闭卷)答案

满分：100分 考试时间：100分钟 任课教师：王世普

第一题答题卡：

小题号12345678910回 答BDDBABCAAC

第二题答题卡：

小题号12345回 答×√√××一、选择题(项1分，共0分请将选择结果填入第一题答题卡)1).

(1)2．A GIF image is sent as email ,What is the content-type (2) .

(2)A．multipart/mixedB．multipart/image

C．image/JPEGD．image/gif

3．A user want to send some forms(表单) Web server using HTTP protocol, the request line method is (3) .

(3)A．GETB．PATCHC．MOVED．POST

4．If a TCP segment carries data along with an acknowledgment, this technology is called (4)4)’s help

5．TCP is a () ransport layer protocol that ensure data to be exchanged reliably by() requires set up connection before data exchanged by ( 7 )-way handshaking.

()A．connectionB．connectionlessC．joinD．disconnection

()A．datagramsB．acknowledgementsC．dataD．segment

()A．oneB．twoC．threeD．four

6A user requests a Web page that consists of a basic HTML file and 5 JPEG image files. dtrans denoting the time to transfer a file. The total time is (8) to request the Web page in Nonpersistent connections mode?

(8)6(2RTT+ dtrans)B. 2RTT+6 dtransC. RTT+6 dtransD.6(RTT+ dtrans)

7．Host A sends a TCP segment (Seq = 1, ACK = 111) to host B and Host B replies with a TCP segment (Seq = 111, ACK = 81). The payload length of the TCP segment from host A to host B is ( 9 ) .

(9)A80 bytes.B．81 bytes.C．82 bytes.D．unknown

8．As a data packet moves from the lower to the upper layers, header are (10)10)、(问题1分，共5分的打“√”错误的“×”，请判断填入二题答题卡)1. The DNS defines a distributed, hierarchical database that provides only hostname to IP address mappings. ( × )

2. In SR protocol, sender only resends pkts for which ACK not received. ( √ )

3．the send window maximum size of GBN protocol is equal to 2k-1.( √ )

4．The UDP header checksum is recomputed at every routers.( × )

5．Suppose that the last SampleRTT in a TCP connection is equal to 1 sec. Then Timeout for the conn