宁波大学计算机网络习题集

1.In communication links, transmission rate means： A、Bandwidth B、propagation speed C、process speed D、router delays 正确答案： A

2.All communication activities in Internet are governed by: A、Protocols B、WebMaster C、Client D、ChinaTelecom 正确答案： A

3.The center of internet structure is: A、Tier-1 ISPs B、Local ISPs C、Root DNS D、NAP 正确答案： A

4.When congest occur in network, which delay become large? A、propagation delay B、queuing delay C、transmission delay

D、processing delay 正确答案： B

5.The internet protocols not define： A、order of messages B、actions taken C、format D、price 正确答案： D

6.The internet protocols not define ： A、actions taken B、order of messages C、hacker D、format 正确答案： C

7.Which is not the types of protocol data unit in TCP/IP? A、frame B、datetime C、segment D、message 正确答案： B

8.Which is not a connected end system device in the internet? A、Mobile Phone

B、PC server C、PC workstation D、Router 正确答案： D

9.All communication activities in network are governed by : A、Protocols B、Servers C、Government D、Clients 正确答案： A

10.For Queueing delay,in which state, average queuing delay small: A、La/R =0.1 B、La/R =0.9 C、La/R > 1 D、La/R >10 正确答案： A

1应用层中的数据块常被称为: A、比特流 B、帧 C、分组 D、消息

正确答案： D

2在TCP/IP 层次协议中，传输层向应用层提供的接口是哪一个? A、Put B、Port C、Socks D、Socket 正确答案： D

3下列哪一组协议属于应用层协议？ A、ICMP,RARP,ARP B、FTP,SMIP,TELNET C、ARP,IP,UDP D、IP,TCP,UDP 正确答案： B

4在互联网WEB应用中以下哪一项扮演了控制角色? A、HTML语言 B、Web客户端 C、HTTP协议 D、Web服务器 正确答案： C

5下面哪一个特征是HTTP协议所不具备的: A、面向对象 B、客服机/服务器

C、无连接 D、无状态 正确答案： C

6IE8.0浏览器默认使用的超文本传输协议是哪一个版本? A、WEB 2.0 B、HTTP1.0 C、HTTP 1.1 D、HTTP 2.0 正确答案： C

7在HTTP协议中，每一个对象的地址都可以标识为： A、UDP B、UML C、UTP D、URL 正确答案： D

8HTTP需要浏览器在每一个请求中递交认证信息，这是因为HTTP协议的哪一个特性？ A、面向连接 B、无连接 C、分布式 D、无状态 正确答案： D

A、不可以 B、可以 C、不知道 D、不确定 正确答案：

4Http1.1中持续/流水线模式时，可以同时在一个socket中传输多个对象吗？ A、不可以 B、可以 C、不知道 D、不确定 正确答案： A

5安全性更好的HTTP协议标准是什么？ A、HTTP2.0 B、HTTPS C、HTML5 D、FLASH 正确答案： B

6互联网上哪个应用不属于WEB2.0？ A、SMS B、SNS C、BLOG D、FACEBOOK

正确答案： A

7Proxy服务器在实现上主要是利用了什么方法？ A、条件更新 B、条件请求 C、动态DNS D、动态IP 正确答案： B

8一个HTTP报文的大小可能是多大？ A、小于1480字节 B、小于64K字节 C、大于64K字节 D、理论上无限制 正确答案： D

9IE8浏览器下允许并发的连接数可能是多少？ A、1 B、2 C、4 D、8

正确答案： C

10下述哪个方法不能向服务器递交信息？ A、head B、get

C、put D、post 正确答案： A

1If you want to find the server of WWW.NBU.EDU.CN，select the DNS search type? A、Type=CName B、Type=NS C、Type=MX D、Type=A 正确答案： D

2Which type of DNS query can return name value of mail server associated with domain name? A、type=NS B、type=CNAME C、type=MX D、type=A 正确答案： C

3If you want to build a Content Distribution Networks，You can the DNS search type for alias： A、Type=CName B、Type=MX

C、Type=NS D、Type=A 正确答案： A

4If you want to find the auhoritative name server of domain NBU.EDU.CN，select the DNS search type? A、Type=CName B、Type=NS C、Type=MX D、Type=A 正确答案： B

5In client host, we need to config IP with: A、Root domain servers B、Top-level domain servers C、Authoritative DNS servers D、Local Name Server 正确答案： D

6Which domain name is wrong? A、cs.un.nl B、cs.keio.ac.jp C、eng.sun.com D、/com/sun/eng 正确答案： D

7In DNS,“I don’t know this name, but ask this server” means: A、authoritative name server B、recursive query C、Local name server D、iterated query 正确答案： D

8There is identification in DNS messages，which is a 16 bit number for query and reply to query uses ： A、same number B、number+1 C、number+8 D、number+16 正确答案： A

9Which is not the reason for decentralize DNS? A、single point of failure B、traffic volume

C、distant centralized database D、copy right 正确答案： D

10Which is wrong for DNS:

A、query and reply messages, both with same message format B、distributed db storing resource records (RR)

A、Delayed ACK. Wait up to 500ms for next segment. If no next segment, send ACK.

B、Immediately send single cumulative ACK, ACKing both in-order segments.

C、Immediately send duplicate ACK, indicating seq. # of next expected byte.

D、Immediate send ACK, provided that segment start at lower end of gap 正确答案： A

8How does TCP sender perceive congestion? A、Go Back to N B、delay event

C、Retransmission event D、Lost event 正确答案： D

9UDP is one of Internet transport-layer protocols, it has: A、No-frills extension of “best-effort” IP B、Connection setup C、Flow control D、Congestion control 正确答案： A

10In TCP, Retransmissions can be triggered by: A、Timeout events

B、Congestion control C、Duplicate datas D、Flow control 正确答案： A

1UDP不存在公平性，UDP有可能会压制TCP传输，TCP是应对这种压制可以采用多线程多连接传输。 正确答案： √

2TCP拆除连接要比建立连接多一次握手，是因为需要双向拆除并双向确认。 正确答案： √

3tcp可以提供流量控制，UDP的应用一定不能提供流量控制。 正确答案： ×

4在TCP协议中，传输的数据有没有优先级的设定，重传的数据包有优先发送权。

正确答案： ×

5TCP协议有拥塞控制策略，网络还会发生拥塞崩溃是因为同时存在UDP，而且TCP拥塞的推断有时间滞后等问题。 正确答案： √

6TCP协议如果双方一直没有收发信息，超过一定时间协议会强制关闭连接。 正确答案： ×

7TCP的ACK可以携带数据乱序和网络拥塞的信息。 正确答案： ×

8可以设计应用采用udp协议发送消息、tcp协议接受消息。 正确答案： ×

9UDP协议下网络拥塞会造成严重丢包。 正确答案： √

10用TCP发送数据时发送端发送数据的速度未知，不会出现接收端来不及接受的问题。 正确答案： ×

1Which is an Inter-AS routing protocols: A、ICMP: Interior ControlMessage Protocol B、IGRP: Interior Gateway Routing Protocol C、BGP: Border Gateway Protocol D、RIP: Routing Information Protocol 正确答案： C

2Which is not a common Intra-AS routing protocols: A、ICMP: Interior Control Message Protocol B、IGRP: Interior Gateway Routing Protocol C、OSPF: Open Shortest Path First D、RIP: Routing Information Protocol 正确答案： A

3Which protocol can assign the individing IP address to the host and router interfaces in its organization ?

A、DHCP B、NAT C、POP3 D、OSPF 正确答案： A

4In Internet Control Message Protocol, if ICMP Data send error then report to whom: A、Source B、Destination C、Route D、None 正确答案： A

5IP Reassembly(after fragmentation) will be in: A、NAT

B、destination node C、source node D、router 正确答案： B

6What is right in datagram network:

A、source address in packet determines next hop B、tag determines next hop

C、destination address in packet determines next hop

D、destination address and port in packet determines next hop 正确答案： C

7What’s a network ? From IP address perspective they can physically reach each other without intervening router and the device interfaces with:

A、same host part of IP address B、same network part of IP address C、same TCP port # D、same IP address 正确答案： B

8Queued datagram at front of router’s queue prevents others in queue from moving forward is:

A、Hops-of-the-List (HOL) blocking B、Head-of-the-List (HOL) blocking C、Hops-of-the-Line (HOL) blocking D、ead-of-the-Line (HOL) blocking 正确答案： B

9NAT router must replace outgoing datagrams with:

A、(source IP address, port #) to (NAT IP address, new port #) B、(source IP address, port #) to (NAT IP address, 3128)

C、(source IP address, port #) to (Source IP address, new port #) D、(source IP address, port #) to (Source IP address, 3128)

C、When a host makes a DNS query, query is sent to its Root DNS server D、distributed database implemented in hierarchy of many name servers 正确答案： C

1When ftp server receives file command, which opens the 2nd TCP connection for file tranfer: A、server or client B、server and client C、client D、server 正确答案： A

2Ftp Client obtains authorization over control connection on port： A、20 B、21 C、25 D、110 正确答案： B

3Which APP protocol use separate control and data connections on to port:

A、Email 110 and 25 B、Ftp 21 and 20 C、Http 80 and 808

D、Telnet 25 and 1025 正确答案： B

4FTP client browses remote directory by sending commands over: A、IP connection B、UDP connection C、data connection D、control connection 正确答案： D

5Which application is usually based on UDP and TCP protocol? A、Network Games B、FTP Download C、Sending E-mail D、Web Browsing 正确答案： A

6在下面列出的TCP/IP命令中，哪一个可以被用来远程登录主机？ A、telnet B、ftp C、login D、tftp 正确答案： A

7In which, FTP data connect can initiation from port 20 on server to hight port on client?

A、Passive FTP B、Active FTP C、SFTP D、TFTP 正确答案： B

8In which, FTP data connect can initiation from high port on client to high port on server? A、Active FTP B、Passive FTP C、SFTP D、TFTP 正确答案： B

9Which is not a sample commands that sent as ASCII text over control channel in FTP? A、USER B、PASS C、LIST D、HEAD 正确答案： D

10Which is not a Sample return codes in FTP? A、304 B、331

C、125 D、425 正确答案： A

1If you want to find the mail server of domain NBU.EDU.CN，select the DNS search type? A、Type=MAIL B、Type=NS C、Type=MX D、Type=A 正确答案： C

2Which is wrong for SMTP:

A、SMTP use two separated connections for outgoing mails B、SMTP server uses CRLF.CRLF to determine end of message C、SMTP requires message (header & body) to be in 7-bit ASCII D、SMTP uses persistent connections 正确答案： A

3Which is not a email application protocol? A、SMNP B、SMTP C、IMAP D、POP3

正确答案： A

4In MIME, Msword is one subtypes of Content-Type: A、Text B、Application C、Image D、Doc 正确答案： B

5In email protocol, which will not be used? A、MINE

B、QP(Quote-Printable) C、Base64 D、CDNS 正确答案： D

6For send email via SMTP, it requires message (header & body) to be in: A、octet-stream B、8-bit ASCII C、7-bit ASCII D、Ziped 正确答案： C

7Which one is a right email address? A、wang$163.com B、wang102&163.com

C、wang#sina.com.cn D、Wang@sina.com.cn 正确答案： D

8Which element are not in Mail Servers:

A、Mailbox contains incoming messages for user

B、Message queue of outgoing (to be sent) mail messages C、SMTP protocol between mail servers to send email messages D、NAT device for outgoing mails 正确答案： D

9Which is not a major components? A、user agents B、mail servers C、simple mail transfer D、gmail 正确答案： D

10SMTP uses TCP to reliably transfer email message from client to server with port: A、21 B、25 C、75 D、110 正确答案： B

1In P2P file sharing, which is easy to shut down by law: A、Query flooding B、decentralized directory C、centralized directory D、pure Clinet/Server 正确答案： C

2In P2P file sharing, in which the group leaders can get overloaded: A、centralized directory B、Query flooding C、decentralized directory D、Pure Clinet/Server 正确答案： C

3C/S, P2P and _____ are three types of application architectures. A、B/S

B、Hybrid of C/S and P2P C、User to user

D、Command and Conquer 正确答案： B

4Which is not a network end system architecture model: A、Client/Server B、Peer-Peer

C、End-End

D、Hybrid Client/Server and Peer-Peer 正确答案： C

5The problems with centralized directory of P2P not include: A、Copyright infringement B、Performance bottleneck C、Bootstrap node needed D、Single point of failure 正确答案： C

6The problems with decentralized directory of P2P maybe: A、Copyright infringement B、Performance bottleneck C、Bootstrap node needed D、Single point of failure 正确答案： C

7In centralized directory of P2P, the disadvantages of approach maybe: A、complex protocol B、bootstrap node needed C、single point of failure

D、group leaders can get overloaded 正确答案： C

8Query flooding is fully distributed，it means：

A、no distributed server B、no central server C、no IP needed D、no water 正确答案： B

9Which one is wrong in P2P decentralized directory?

A、Each peer is either a group leader or assigned to a group leader B、Group leader tracks the content in all its children C、Peer queries other peers

D、Group leader may query other group leaders 正确答案： C

10which one is wrong in P2P with centralized directory？ A、peer is decentralized, B、file transfer is decentralized

C、locating content is highly centralized D、locating content is highly decentralized 正确答案： D

1邮件发送方显示邮件已经发送成功，可是有的时候接受方却没有接受到邮件，那是因为显示的仅仅为客户端发送到自己的SMTP服务器成功了。 正确答案： √

2邮件传输过程可以省略中间服务器的转发，可否直接传输到对方的邮件服务

器。

正确答案： √

3书上说http方式是一个请求、一个封装、一个对象进行传送的，而我们平时通过浏览器发邮件时可以同时发送多个附件，这是矛盾的。 正确答案： ×

4EMAIL传输文件时，可以区分文件类型，文本文件使用TCP/IP协议传输，视频文件使用UDP协议传输，这样传输速度会更快。 正确答案： ×

5有时在QQ邮箱发送邮件，会挺久后才显示在发送中，可是文件本身并不大呀，这是因为邮件服务器的排队发送的队列可能比较长。 正确答案： √

6邮件服务器之间的邮件传送使用SMTP协议，客户端往邮件服务器发送邮件采用POP3协议。 正确答案： ×

7SMTP要求必须在提供了账户名和密码之后才可以登录 SMTP 服务器，这就可以彻底防止那些垃圾邮件。 正确答案： ×

8IMAP协议可以阅读邮件，但是不可以发送邮件，邮件客户端发送邮件必须用SMTP。 正确答案： √

9Base64的编码方式不能解决繁体汉字的邮件处理。 正确答案： ×

D、NAP 正确答案： A

19In which network, propagation delay maybe greater then queuing delay？

A、Fiber Network B、Wire LAN

C、Satellite Network D、WIFI Network 正确答案： C

20In MIME, Msword is one subtypes of Content-Type: A、Text B、Application C、Image D、Doc 正确答案： D

二、 多选题（题数：10，共 20 分） 1A system view of the Internet include: A、Millions of connected computing devices B、Communication links C、Circuit D、Routers E、Protocols

正确答案： ABDE

2Which are the problems with centralize DNS? A、single point of failure B、traffic volume

C、distant centralized database D、stateless

E、maintenance not easy 正确答案： ABCE

3Which Method types are in HTTP/1.0: A、GET B、POST C、HEAD D、PUT

正确答案： ABC

4How do connect end systems to edge router: A、Network of relationships B、Mobile access networks C、Institutional access networks D、Residential access networks 正确答案： BCD

5What are the major components of email? A、user agents

B、mail servers

C、simple mail transfer protocol D、mail store protocols E、mail access protocols 正确答案： ABCE

6In Client-server architecture, clients can be: A、Communicate directly with each other B、Have dynamic IP addresses C、Intermittently connected D、Communicate with server 正确答案： BCD

7In Client-server architecture, server can be: A、Always-on host B、Permanent IP address C、Server farms for scaling D、Initalize connection to client 正确答案： ABC

8Application-layer protocol defines： A、Types of messages exchanged B、Syntax of message types C、Semantics of the fields

D、Rules for when and how processes send& respond to messages

E、Port number of servers 正确答案： ABCD 9

In which Queuing delay state, more “work”arriving than can be serviced, average delay is infinite?

R=link bandwidth (bps) L=packetlength (bits) a=averagepacket arrival rate A、La/R ~ 0.1 B、La/R ~ 0.2 C、La/R ~ 1.1 D、La/R ~ 1.2 E、La/R ~ 2.0 正确答案： CDE 10Web caching can：

A、Reduce response time for client request. B、Reduce traffic on an institution’s access link. C、Result in Providers to effectively deliver content D、Guarantee QOS 正确答案： ABC

三、 判断题（题数：10，共 20 分）

1With SMTP, it is possible to send multiple mail messages over the same TCP connection.

正确答案： √

2If a POP3 client does not send the dele command, copies of the messages that theclient has retrieved remain in the mail server. 正确答案： √

3The Date: header in the HTTP response message indicates when the object in the response was last modified. 正确答案： √

4邮件服务器之间的邮件传送使用SMTP协议，客户端往邮件服务器发送邮件采用POP3协议。 正确答案： ×

5IMAP协议可以阅读邮件，但是不可以发送邮件，邮件客户端发送邮件必须用SMTP。 正确答案： √

6DNS lookups often involve a combination of recursive and iterative queries. 正确答案： √

7有时在QQ邮箱发送邮件，会挺久后才显示在发送中，可是文件本身并不大呀，这是因为邮件服务器的排队发送的队列可能比较长。 正确答案： √

8Base64的编码方式不能解决繁体汉字的邮件处理。 正确答案： ×

9The Date: header in the HTTP response message indicates when the

object in the response was last modified. 正确答案： √

10Itis possible for a mail client to send e-mail messages over HTTP rather than SMTP. 正确答案： √

1在TCP/IP协议簇的层次中，解决不同计算机的进程之间通信问题是在（ ） A、网络层 B、应用层 C、接口层 D、传输层 正确答案： D

2What is FSM in Reliable data transfer? A、Feedback Shift Mark B、Frequency Shift Manage C、Finite state machines D、Foreign Service machines 正确答案： C

3One of Internet transport-layer protocols is TCP, it provider services A、Access control

B、Reliable, in-order delivery C、Delay guarantees

D、Bandwidth guarantees 正确答案： B

4In GBN,when receiver receive a out-of-order packet,then discard and re-ACK the packet with: A、lowest in-order port # B、highest in-order port # C、lowest in-order sequence # D、highest in-order sequence # 正确答案： D

5RDT Handle duplicates, sender adds what to each packet: A、Phone number B、Socket number C、Sequence number D、TTL value 正确答案： C

6In RDT Approachs, which is designed for performance: A、ACK or NAK B、sequence # C、pipeline D、checksum 正确答案： C

7In RDT protocol, which can increase the use of physical resources:

A、Checksum B、ACK C、Pipeline D、Timer 正确答案： C

8In channel with bit errors, RDT recover from errors need: A、AMD B、ARQ C、ARP D、ACKs 正确答案： D

9In RDT Approachs, which is designed for bit error: A、checksum B、pipeline C、sequence # D、ACK or NAK 正确答案： A

10UDP协议能够提供的服务是： A、流量控制 B、拥塞控制 C、连接管理 D、端到端传输

正确答案： D

1TCP Flow Control is a speed-matching service for:

A、keep the send rate large then the sender application's drain rate B、keep the send rate large then the receiving application's drain rate C、matching the send rate to the sender application's drain rate D、matching the send rate to the receiving application's drain rate 正确答案： D

2Which one is not the mechanism of TCP Congestion Control: A、Conservative after timeout events B、slow start C、FIFO D、AIMD 正确答案： C

3Which event will not be in TCP Receiver:

A、Arrival of segment that partially or completely fills gap

B、Arrival of out-of-order segment higher-than-expect seq. # . No gap detected.

C、Arrival of in-order segment with expected seq #. One other segment has ACK pending.

D、Arrival of in-order segment with expected seq #. All data up to expected seq # already ACKed.

正确答案： B

4Which of the following measures the time from one segment transmission to ACK receipt: A、largest RTT B、estimation RTT C、sample RTT D、double RTT 正确答案： C

5In the mechanism of TCP Congestion Control, AIMD means: A、after input/must decrease

B、additive increase/multiplicative decrease C、after increase/must decrease D、additive input/multiplicative decode 正确答案： B

6In today's internet, the approaches towards congestion control is A、End-End congestion control

B、Network-assisted congestion control C、Step-By-Step congestion control D、Qos 正确答案： A

7In event of TCP Receiver, when arrival of in-order segment with expected seq #. All data up to expected seq # already ACKed, then:

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