软考中级
根据下面的文字资料回答 71～75 题 connected by（ 1 ）or Hubs,which just move the bits from one network to an identical network. One layer up we find bridgas and swiehes,which operate at data link layer. They can accept （ 2 ） , examine the MAC address, and forward the fra
题目
根据下面的文字资料回答 71～75 题 connected by（ 1 ）or Hubs,which just move the bits from one network to an identical network. One layer up we find bridgas and swiehes,which operate at data link layer. They can accept （ 2 ） , examine the MAC address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer,we have touters that can connect two netwoks. If two networks have（ 3 ）network layer,the router may be able to translate between the packet formats. In the transport layer we find transport gateway, which cart interface between the two transport connections. Finally, in the application layer, application gateways translate message（ 4 ）. As an example,gateways between Internet e-mail and X.400 e-mail must （ 5 ）the e-mail message and change various header fields.
第6题：文中（ 1 ）处正确的答案是（ ）。
A．reapers
B．relays
C．connects
D．modems
参考答案和解析
网络可以用不同的设备互联。在物理层，用中继器或者集线器互联，这些设备只是在相同的网络之间传送比特串。在上面的数据链路层，可以使用网桥或者交换机，这些设备接收数据帧，检查MAC地址，并可以实瑰少量的协议转换，把数据帧转发到不同的网络中。在网络层，使用路由器连接两个网络。如果两个网络的网络层不同，路由器能够对分组格式进行转换。在传输层，使用传输网关，它可以在两个传输连接之间建立接口。最后，在应用层，应用网关实现消息语法之间的翻译。例如，在Internet邮件和X．400邮件之间的网关可以对邮件报文进行语法分析，对报文的各个头字段做出改变。
相似问题和答案
第1题：
根据下面的文字资料回答 71～75 题 The Simple Network Management Protocol(SNMP)is an （ 1 ）protocol that facilitates the exchange of management information between （ 2 ）．It is part of the Transmission Control ProtocoL/Internet Protocol(TCP/IP)protocol suite. SNMP enables network（ 3 ）to manage network performance，find and sole network problems，and plan for（ 4 ）．An SNMP managed network consists of three key components：managed devices，（ 5 ），and networkmanagement systems．
第6题：文中（ 1 ）处正确的答案是（ ）。
A．Physical Layer
B．Link Layer
C．Network Layer
D．Transport Layer
简单网络管理协议(SNMP)是一种传输屡的协议，利用它可以在不同的网络设备之间交换管理信息。它是TCP/IP协议簇的一部分。SNMP使网络管理员能够管理网络的性能，发现和解决网络中的问题并为网络网络扩张作规划。一个SNMP管理网络包括三个主要组件：管理设备，代理和网络管理系统。
第2题：
●Which is the second layer from the bottom in Open System Interconnection Reference Model? (71)．
(71) A. Application
B.Data link
C.Network
D.Session
第3题：
根据下面的文字资料回答 71～75 题In the following essay，each blank has fourchoices．Choose the best answer and write down on thean，swer sheet．
Microwave communication uses（ 1 ）frequency radio waves that travel instraighdine sthroughthe air．Because the waves cannot（ 2 ）with the curvature of the earth，they can be （ 3 ）onlyover short distance．Thus，microwave is a good（ 4 ）for sending data between bulldingsin a city or on a large college campus．For longer distances，the waves must berelayed by means of“dishes”or（ 5 ）．These can be installed on towers，highbuildings，and mountain tops．
第71题：文中（ 1 ）处正确的答案是（ ）。
A．high
B．10w
C．1ong
D．short
微波通信利用在空气中直线传播的高频无线电波通信，因为电磁波不能随着地球表面的曲度而弯曲，所以只能用来在短距离内传输。这样，微波就是一种在大楼之间或在大的大学校园里用来发送数据的优良介质。如果要进行更长距离的传输，电磁波必须通过蝶行卫星天线或普通天线中转。这些天线能够被安装在塔顶、高楼和山顶上。
第4题：
● Every valid character in a computer that uses even （71） must always have an even number of1bits.
（71）A. parity B. check C. test D. compare
● The maximum number of data that can be expressed by 8 bits is （72） .
（72）A. 64 B. 128 C. 255 D. 256
● Integration （73） is the process of verifying that the components of a system work together as described in the program design and system design specifications.
（73）A. trying B. checking C. testing D. coding
● GIF files are limited to a maximum of 8 bits/pixel, it simply means that no more than 256 colors are allowed in （74） .
（74）A. an image B. a file C. a window D. a page
● Computer （75） is a complex consisting of two or more connected computing units, it is used for the purpose of data communication and resource sharing.
（75）A. storage B. device C. network D. processor
第5题：
● An internet is a combination of networks connected by （71） . When a datagram goes from a source to a （72） , it will probably pass many （73） until it reaches the router attached to the destination network. A router receives a （74） from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available （75） is the optimum pathway?
（71）
A. modems
B. routers
C. switches
D. computers
（72）
A. user
B. host
C. city
D. destination
（73）
A. destinations
B. routers
C. packets
D. computers
（74）
A. destination
B. resource
C. packet
D. source
（75）
A. pathways
B. routers
C. diagrams
D. calls
第6题：
根据下面的文字资料回答 71～75 题 In the following essay．each blank has four choices．Choose the best answer and write down on the answer sheet．
Spread spectrum simply means that data is sent in（ 1 ）pieces over a number of the discrete frequencies available for use at any time in the specified range．Devices using（ 2 ） spread spectrum(DSSS)communicate by splitting each（ 3 ）of data into several parts and sending them concurrently on different（ 4 ），DSSS uses a lot of the available（ 5 ），about 22 megahertz(MHz)．
第71题：文中（ 1 ）处正确的答案是（ ）。
A．small
B．high
C．low
D．long
的设备相互之间通信是通过把每个字节的数据分成几个部分在不同的频率上同时传送。直序扩频使用了大约22 Mb的有效带宽。
第7题：
根据下面的文字资料回答 71～75 题 In the following essay，each blank has four choices．Choose the most suitable one from the four choices and write down in the answer sheet．A（ 1 ）is basically an end point of a communication link between two applications.Sockets that extend over a network connect two or more applications running on separate computer sat tached to the network．Asocket（ 2 ）twoaddresses：（ 3 ）．Sockets providea （ 4 ）communication channel between one or more systems.There are stream and datagram sockets separately using TCP and（ 5 ）．
第6题：文中（ 1 ）处正确的答案是（ ）。
A．program
B．UDP
C．socket
D．TCP
第8题：
根据下面的文字资料回答 72～76 题 （ 1 ）is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed-length bit string．
（ 2 ）is a protocol that most USENET machines nOW use it to allow news articles to propagate from one machine to another over a reliable connection．
（ 3 ）is an approach preferred by cable TV providers．In this solution the fiber terminates at an optoelectrical converter and the final segment is a shared coaxial cable．
（ 4 ）is a device used to connect two separate network that use different communication protocol．
（ 5 ）is a digital-to-digital polar encoding method in which the signal level is always either positive or negative．
第6题：文中（ 1 ）处正确的答案是（ ）。
A．MD
B．RSA
C．DES
D．MIB
MD是一种单向的在利用任意长度的文本来计算固定长度的字符串的功髓；NNTP是一种非常流行的新闻机制协议，现在我们利用它通过可靠的连接传播新的文章；HFC是一种更受有线电视提供商欢迎的接入方法，利用这种方法，光纤中止于广电转换器，最后一段通过共享式同辅电缆传输；网桥是一种用来涟接两个采用了不同通信协议的网络的设备；非零编程(NRZ)是一种数字编码技术，在它的编码中要么正电平要么负电平。
第9题：
Every valid character in a computer that uses even(71)must always have an even number of 1 bits．(71)
A．parity
B．check
C．test
D．compare
解析：计算机中采用偶校验的每个字符一定含有偶数个1。
第10题：
●Networks can be interconnected by different devices．In the physical layer，networks can be connected by (66) or Hubs，which just move the bits from one network to an identical network．One layer up we find bridgas and swiehes,which operate at data link layer．They can accept (67) ，examine the MAC address，and forward the frames to a different network while doing minor protocol translation in the process．In the network layer，we have routers that can connect two netwoks．If two networks have (68) network layer，the router may be able to translate between the packet formats．In the transport layer we find transport gateway，which can interface between the two transport connections．Finally，in the application layer，application gateways translate message (69) ．As an example，gateways between Internet e-mail and X．400 e-mail must (70) the e-mail message and change various header fields．
(66) A．reapers
B．relays
C．connects
D．modems
(67) A．frames
B．bytes
C．packages
D．cells
(68) A．special
B．dependent
C．similar
D．dissimilar
(69) A．syntax
B．semantics
C．languages
D．format
(70) A．analyze
B．pairs
C．delete
D．create
【解析】网络可以用不同的设备互联。在物理层，用中继器或者集线器互联，这些设备只是在相同的网络之间传送比特串。在上面的数据链路层，可以使用网桥或者交换机，这些设备接收数据帧，检查MAC地址，并可以实现少量的协议转换，把数据帧转发到不同的网络中。在网络层，使用路由器连接两个网络。如果两个网络的网络层不同，路由器能够对分组格式进行转换。在传输层，使用传输网关，它可以在两个传输连接之间建立接口。最后，在应用层，应用网关实现消息语法之间的翻译。例如，在Internet邮件和X．400邮件之间的网关可以对邮件报文进行语法分析，对报文的各个头字段做出改变。