計(jì)算機(jī)網(wǎng)絡(luò)第二次平時(shí)考試

1、計(jì)算機(jī)網(wǎng)絡(luò)平時(shí)考試試題（帶答案）一、選擇題1In the Ethernet frame structure, the Data field carries the ( ).A.IP datagram B.segment C.frame D.message2The units of data exchanged by a link-layer protocol are called ( ).A. Frames B. SegmentsC. Datagrams D. bit streams3The SYN segment is used for ( ).A.TCP connection setup

2、B.TCP flow controlC.TCP congestion control D.Closing a TCP connection4The ( ) is a worldwide computer network, that is, a network that interconnects millions of computing devices throughout the world. A. Internet B. Intranet C. switch net D. television net5The units of data exchanged by a link-layer

3、 protocol are called ( ).A. Frames B. SegmentsC. Datagrams D. bit streams6In Address：,（ ） indicates “host name”.A. www B. uzz C. edu D. cn 7. In the following options, which belongs to the network core? ( )A. end systems B. routers C. clients D. servers8The Internets connection-oriented service has

4、a name, it is ( ).A.TCP B.UDP C.TCP/IP D.IP9There are two fundamental approaches to building a network core, ( ) and packet switching.A. electrical current switching B. circuit switchingC. data switching D. message switching10A ( ) protocol is used to move a datagram over an individual link.A. appli

5、cation-layer B. transport-layerC. network-layerD. link-layer11Services provided by transport layer include ( ).A.HTTP and FTP B.TCP and IP C.TCP and UDP D.ICMP 12, the network address for this network is ( ).A.48 B. 50 C. D. 13IP belongs to ( ).layer? A.transport

6、 B.network C.data link D. physical 14Which of the following is correct? ( )A. No two adapters have the same MAC address.B. MAC broadcast address is FF-FF-FF-FF-FF-FF.C. A portable computer with an Ethernet card always has the same MAC address, no matter where the computer goes. ( ).D. All of the abo

7、ve15How many bits specify the IP protocol version in a datagram? ( ).A.1 bit B.2 bits C.4 bits D.8 bits16In the following applications, which one is a loss-tolerant application? A E-mail B file transfer C instant messaging D real-time audio18The Internet mail system has three components which they a

8、re ( ).A.user agent, SMTP, POP3 B.SMTP, POP3, IMAPC.user agent, SMTP, IMAP D.user agent, SMTP, mail server19DNS means ( ).A.Data Name System B.Data National SystemC.Domain Name System D.Domain National System2024”, where the /24 notation, sometimes known as a ( ).A. Subnet mask B. Networking address

9、C. Host addressD. None of above21Which of the following is not intra-AS routing protocol? ( )A. RIP B. OSPF C. IGRP D.BGP 22IP ad, the network address for this network is ( ).A. B. 50 C. D. 23IP Data-grams are rarely larger than ( ).A. 1500 bytes B. 65535 bytes C.500 bytes D

10、.1024 bytes24Which of the following is correct? ( )A. No two adapters have the same MAC address.B. MAC broadcast address is FF-FF-FF-FF-FF-FF.C. A portable computer with an Ethernet card always has the same MAC address, no matter where the computer goes. D. All of the above25Which of the following i

11、s not belonging to channel partitioning protocols? ( )A.CSMA B.FDM C.CDMA D.TDM26. MAC address is ( ) bits long.A.32 B.48 C.128 D.6427The Internets connection-oriented service has a name, it is ( ).A.TCP B.UDP C.TCP/IP D.IP28In the LAN, ( ) protocol dynamically assign IP addresses to hosts.A.DNS B.A

12、RP C.DHCP D.IP29Which layer provides host-to-host services? ( ).A. transport B. network C. data link D. physical30DHCP protocol is a four-step process: DHCP request. DHCP ACK. DHCP server discovery. DHCP server offer(s). The correct sequence is ( )A. B. C. D.31In the Ethernet frame structure, the CR

13、C field is ( ) bytes.A.2B.4C.8D.3232Transport-layer protocols run in ( ).A.Servers B.Clients C.Routers D.End system33The maximum amount of data that can be grabbed and placed in a segment is limited by the( ).A. Maximum segment size (MSS)B. MTUC. ChecksumD. Sequence number34The internets network lay

14、er provides a single service-that is ( ).A. Reliable data transfer B. Flow controlC. Congestion control D. Best-effort-service35There are 6 flag fields. Which one is to indicate that the receiver should pass the data to the upper layer immediately? ( )A. PSH B. URG C. ACK D. RST36ICMP is used for (

15、).A. Reliable data transfer B. Error reporting C. Flow control D.Congestion control37The FIN segment is used for ( ).A. TCP connection setup B. TCP flow controlC. TCP congestion control D. Closing a TCP connection38A transport-layer protocol provides for logical communication between ( ).A. Applicat

16、ion processesB. Hosts C. RoutersD. End systems39Port numbers scope is ( ) to ( ). A. 0, 1023 B. 0, 65535 C. 0, 127 D. 0,2554024”, where the /24 notation, sometimes known as a( ).A. Subnet maskB. Networking addressC. Host addressD. None of above二、判斷題1In CSMA/CD, one node listens to the channel before

17、 transmitting. T2In C/S architecture, client has a fixed well-known address. F3In P2P architecture, peers communicate with each other directly. T4Each TCP connection is closed after the server sending one object.5There are four steps in DHCP, the DHCP server can complete DHCP response.F6In full-dupl

18、ex transmission(s), the nodes at both ends of a link may transmit packets at the same time. T7DNS resolves hostnames for hosts anywhere in the Internet. T8ARP resolves an IP address to a MAC address. T9In the broadcast packet of DHCP DISCOVER，source IP address is .0. T10The routing algorithm running

19、 within an autonomous system is called an intra-AS routing protocol. F11In CSMA/CD, one node listens to the channel before transmitting. TT12All of the Ethernet technologies provide connection-oriented reliable service to the network layer. F 13A router receives a packet, in which TTL=0, and the pac

20、ket will be dropped. T14. Datagram networks are circuit-switched networks, and virtual-circuit networks are packet-switched networks. F15ARP resolves an IP address to a MAC address. T16If the traffic intensity is close to zero, the average queuing delay will be close to zero. T17A router receives a

21、packet, in which TTL=0, and the packet will be dropped. T18The adapter is also called as NIC. T19Consider CRC error checking approach, the four bit generator G is 1011, and suppose that the data D is 10101010, then the value of R is 010. F20Hubs can interconnect different LAN technologies. F三、填空題1.

22、Common Channel multiplexing technology includes _FDM_、_TDM_、_WDM_、_CDM_.2NIC works in _data link_ layer of Internet.3. _network_ layer provides host-to-host services, and _transport_ layer provides process-to-process services.4MAC address is _48_ bits, and IPV4 has a 32_ bit address.5The data transm

23、ission delay include: _propagation delay_、_transmission delay_、processing delay and queuing delay.6The port number used by HTTP is _80_；The port number used by SMTP is _25_；The port number used by DNS is _53_.7在TCP連接建立過(guò)程中，客戶端向服務(wù)器發(fā)送一個(gè)連接請(qǐng)求的TCP報(bào)文，其中包含連接的初始序列號(hào)v和一個(gè)窗口大小，服務(wù)器收到報(bào)文后，向客戶端發(fā)送一個(gè)請(qǐng)求確認(rèn)的報(bào)文，其中包含它選擇的初始

24、序列號(hào)w確認(rèn)號(hào)為_(kāi)V+1_，和一個(gè)窗口大小。四簡(jiǎn)答題1比較TCP協(xié)議和UDP協(xié)議之間的異同點(diǎn)。2比較分組交換和電路交換之間的優(yōu)缺點(diǎn)。3簡(jiǎn)述HTTP代理服務(wù)器的作用。4數(shù)據(jù)鏈路層的三個(gè)基本問(wèn)題是什么？簡(jiǎn)單論述一下。5簡(jiǎn)述兩種DNS服務(wù)器查詢方式。6簡(jiǎn)單論述CSMA/CD的工作原理。7. 簡(jiǎn)述TCP的三次握手協(xié)議。五、應(yīng)用題1一個(gè)自治系統(tǒng)有5個(gè)局域網(wǎng)，其連接圖如圖所示，LAN2LAN5的主機(jī)數(shù)為：93，147，23，20。該自治系統(tǒng)分配到的IP地址快為199.138.118/23。試給出每一個(gè)局域網(wǎng)的地址塊（包括前綴）。（10分）24x31，接收方收到的數(shù)據(jù)是否是正確的？（請(qǐng)寫(xiě)出判斷依據(jù)及推演過(guò)程

25、）（5分）3用Ethereal工具捕獲到如下數(shù)據(jù)包，請(qǐng)根據(jù)圖的內(nèi)容回答如下問(wèn)題。（8分）（1）本次應(yīng)用基于應(yīng)用層的_協(xié)議，基于傳輸層的_協(xié)議。（2）上圖中，數(shù)據(jù)包133是一個(gè)_數(shù)據(jù)包，134是一個(gè)_數(shù)據(jù)包，135是一個(gè)_數(shù)據(jù)包。（A. 連接接受 B. 連接確認(rèn) C. 連接請(qǐng)求）（3）查看Packet Detail窗口信息，可以看出：133數(shù)據(jù)包的源端口號(hào)為_(kāi)，目的端口號(hào)為_(kāi)，表示這是一個(gè)從_到_的數(shù)據(jù)包（填寫(xiě)Client或者Server）。（4）此數(shù)據(jù)包的傳輸層首部長(zhǎng)度為_(kāi)字節(jié)，其中固定首部長(zhǎng)度為_(kāi)字節(jié)，標(biāo)識(shí)字段都有URG、ACK、PSH、RST、SYN、_共六種，其中數(shù)據(jù)包136的控制字段應(yīng)為_(kāi)=1 &&_=1。4有如下的四個(gè)/24地址塊，試進(jìn)行最大可能的聚合。，。（8分）5現(xiàn)有五個(gè)站分別連接在三個(gè)局域網(wǎng)上，并且用兩個(gè)透明網(wǎng)橋連接起來(lái)，如下圖所示。每一個(gè)網(wǎng)橋的兩個(gè)