【计算机类职业资格】网络管理员-计算机专业英语(二)及答案解析.doc

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1、网络管理员-计算机专业英语(二)及答案解析(总分：90.00，做题时间：90 分钟)一、单项选择题(总题数：9，分数：90.00)Traditional network layer packet forwarding relies on the information provided by network layer _ protocols, or static routing, to make an independent _ decisions at each hop within thenetwork. The forwarding _ is based solely on the d

2、estination _ IP address. All packets for thesame destination follow the same path across the network if no other equal-cost paths exist.Whenever a router has two equal-cost _ toward a destination, the packets toward the destinationmight take one or both of them, resulting in some degree of load shar

3、ing.（分数：10.00）(1).A. rotating B. routing C. transmission D. management（分数：2.00）A.B.C.D.(2).A. forwarding B. connecting C. routing D. killing（分数：2.00）A.B.C.D.(3).A. connecting B. window C. decision D. destination（分数：2.00）A.B.C.D.(4).A. anycast B. multicast C. broadcast D. unicast（分数：2.00）A.B.C.D.(5).

4、A. paths B. states C. systems D. connections（分数：2.00）A.B.C.D.A management domain typically contains a large amount of management information. Each individual item of _ information is an instance of a managed object type. The definition of arelated set of managed _ types is contained in a Management

5、Information Base(MIB) module. Many such MIB modules are defined. For each managed object type it describes, a MIB_ defines not only the semantics and syntax of that managed object type, but also the method ofidentifying an individual instance so that multiple _ of the same managed object type can be

6、distinguished. Typically, there are instances of each managed object _ within a managementdomain.（分数：10.00）(1).A. rotation B. switch C. management D. transmission（分数：2.00）A.B.C.D.(2).A. path B. object C. route D. packet（分数：2.00）A.B.C.D.(3).A. connection B. window C. module D. destination（分数：2.00）A.B

7、.C.D.(4).A. packets B. searches C. states D. instances（分数：2.00）A.B.C.D.(5).A. device B. state C. type D. packet（分数：2.00）A.B.C.D.We have already covered the topic of network addresses. The first _ in a block (in class A, B, and C) defines the network address. In classes A, B, and C, if the hosted is

8、all 1 s, the addressis called a direct broadcast address. It is used by a _ to send a packet to all hosts in a specificnetwork. All hosts will accept a packet having this type of destination address. Note that thisaddress can be used only as a _ address in an IP packet. Note also that this special a

9、ddressalso reduces the number if available hosted for each netid in classes A, B, and C.In classes A, B, and C, an address with all 1 s for the netid and hosted (32 bits) define a _ address in the current network. A host that wants to send a message to every other hosts can use this address as desti

10、nationaddress in an IP packet. However, a router will block a packet having this type of address to confine thebroadcasting to the _ network. Note that this address belongs to class E.（分数：10.00）(1).A. datagram B. function C. address D. service（分数：2.00）A.B.C.D.(2).A. router B. switch C. hub D. firewa

11、ll（分数：2.00）A.B.C.D.(3).A. source B. destination C. local D. remote（分数：2.00）A.B.C.D.(4).A. unicast B. multicast C. broadcast D. anycast（分数：2.00）A.B.C.D.(5).A. neighbor B. next C. remote D. local（分数：2.00）A.B.C.D.One of the main responsibilities of ICMP is to report _. Although technology has produced

12、increasingly reliable transmission media, errors still exist and must be handled. IP is an _ protocol. This means that error checking and error control are not a concem ofIP JCMP wasdesigned, in part, to compensate for this shortcoming. Howerver, ICMP does not _ errors, itsimply reports them. Error

13、correction is left to the higher-level protocols. Error messages arealways sent to the original _ because the only information available in the datagram aboutthe route is the source and destination 1P addresses. ICMP uses the source IP address to send theerror massage to the source of the _.（分数：10.0

14、0）(1).A. numbers B. functions C. strings D. Errors（分数：2.00）A.B.C.D.(2).A. reliable B. unreliable C. available D. Unavailable（分数：2.00）A.B.C.D.(3).A. correct B. conduct C. produce D. Connect（分数：2.00）A.B.C.D.(4).Auser Bdestination Csource DProgram（分数：2.00）A.B.C.D.(5).Adatagram Bframe Cservice DProtocol

15、（分数：2.00）A.B.C.D.The presentation layer is concerned with the _ and semantics of the information exchanged between two systems. The processes in two systems are usually exchanginginformation in the form of character _, numbers, and so on. The information should bechanged to bit _ before being transm

16、itted. Because different encoding systems, thepresentation layer is responsible for _ between these different encoding methods. Thepresentation layer at the sender changes the information from its sender-dependent format into acommon format. The presentation layer at the receiving machine changes th

17、e common format intoits _ dependent format.（分数：10.00）(1).A. frequency B. syntax C. dialog D. format（分数：2.00）A.B.C.D.(2).A. numbers B. functions C. strings D. codes（分数：2.00）A.B.C.D.(3).A. systems B. characters C. layers D. streams（分数：2.00）A.B.C.D.(4).A. capability B. interoperability C. reliability D

18、. dependability（分数：2.00）A.B.C.D.(5).A. receiver B. user C. server D. customer（分数：2.00）A.B.C.D.A transport layer protocol has several responsibilities, One is to create a process-to-process (program-to-program) communication; TCP uses port _ to accomplish this. Anotherresponsibility of a transport la

19、yer protocol is to create a _ and error-control mechanism atthe transport level. TCP uses a sliding _ protocol to achieve flow control. It uses theacknowledgment packet, time-out, and retransmission to achieve _ control. The transportlayer is also responsible for providing a connection mechanism for

20、 the application program. Theapplication program sends _ of data to the transport layer. It is the responsibility of thetransport layer at the sending station to make a connection with the receiver.（分数：10.00）(1).A. numbers B. connection C. diagrams D. resources（分数：2.00）A.B.C.D.(2).A. procedure B. fu

21、nction C. route D. flow（分数：2.00）A.B.C.D.(3).A. path B. window C. frame D. diagram（分数：2.00）A.B.C.D.(4).A. packet B. time C. error D. phase（分数：2.00）A.B.C.D.(5).A. ports B. streams C. packets D. cells（分数：2.00）A.B.C.D.Both bus and tree topologies are characterized by the use of multipoint _. For the bus

22、, all stations attach, through appropriate hardware _ known as a tap, directly to alinear transmission medium, or bus. Full-duplex operation between the station and the tap allowsdata to be transmitted onto the bus and received from the _. A transmission from anystation propagates the length of the

23、medium in both directions and can be received by all other_. At each end of the bus is a _, which absorbs any signal, removing it from thebus.（分数：10.00）(1).A. medium B. connection C. token D. resource（分数：2.00）A.B.C.D.(2).A. processing B. switching C. routing D. interfacing（分数：2.00）A.B.C.D.(3).A. tre

24、e B. bus C. star D. ring（分数：2.00）A.B.C.D.(4).A. routers B. stations C. servers D. switches（分数：2.00）A.B.C.D.(5).A. tap B. repeat C. terminator D. concentrator（分数：2.00）A.B.C.D.For _ service, we need a virtual-circuit subnet. Let us see how that works. The idea behind virtual circuits is to avoid havin

25、g to choose a new _ for every packet sent. Instead,when a connection is established, a route from the _ machine to the destination machine ischosen as part of the connection setup and stored in tables inside the _. That route is used forall traffic flowing over the connection, exactly the same way t

26、hat the telephone system works.When the connection is released, the virtual circuit is also terminated. With connection-orientedservice, each packet carries an _ telling which virtual circuit it belongs to.（分数：10.00）(1).A. connectionless B. connection-oriented C. datagram D. telegram（分数：2.00）A.B.C.D

27、.(2).A. processor B. device C. route D. terminal（分数：2.00）A.B.C.D.(3).A. source B. route C. destination D. host（分数：2.00）A.B.C.D.(4).A. connections B. resources C. bridges D. routers（分数：2.00）A.B.C.D.(5).A. address B. identifier C. interface D. element（分数：2.00）A.B.C.D.An internet is a combination of ne

28、tworks connected by _. When a datagram goes from a source to a _, it will probably pass many _ until it reaches the routerattached to the destination network. A router receives a _ from a network and passes it toanother network. A router is usually attached to several networks. When it receives a pa

29、cket, towhich network should it pass the packet? The decision is based on optimization: Which of theavailable _ is the optimum pathway?（分数：10.00）(1).A. modems B. routers C. switcher D. computers（分数：2.00）A.B.C.D.(2).A. user B. host C. city D. destination（分数：2.00）A.B.C.D.(3).A. destinations B. routers

30、 C. packets D. computers（分数：2.00）A.B.C.D.(4).A. destination B. resource C. packet D. source（分数：2.00）A.B.C.D.(5).A. pathways B. routers C. diagrams D. calls（分数：2.00）A.B.C.D.网络管理员-计算机专业英语(二)答案解析(总分：90.00，做题时间：90 分钟)一、单项选择题(总题数：9，分数：90.00)Traditional network layer packet forwarding relies on the inform

31、ation provided by network layer _ protocols, or static routing, to make an independent _ decisions at each hop within thenetwork. The forwarding _ is based solely on the destination _ IP address. All packets for thesame destination follow the same path across the network if no other equal-cost paths

32、 exist.Whenever a router has two equal-cost _ toward a destination, the packets toward the destinationmight take one or both of them, resulting in some degree of load sharing.（分数：10.00）(1).A. rotating B. routing C. transmission D. management（分数：2.00）A.B. C.D.解析：(2).A. forwarding B. connecting C. rou

33、ting D. killing（分数：2.00）A. B.C.D.解析：(3).A. connecting B. window C. decision D. destination（分数：2.00）A.B.C. D.解析：(4).A. anycast B. multicast C. broadcast D. unicast（分数：2.00）A.B.C.D. 解析：(5).A. paths B. states C. systems D. connections（分数：2.00）A. B.C.D.解析：A management domain typically contains a large a

34、mount of management information. Each individual item of _ information is an instance of a managed object type. The definition of arelated set of managed _ types is contained in a Management Information Base(MIB) module. Many such MIB modules are defined. For each managed object type it describes, a

35、 MIB_ defines not only the semantics and syntax of that managed object type, but also the method ofidentifying an individual instance so that multiple _ of the same managed object type can bedistinguished. Typically, there are instances of each managed object _ within a managementdomain.（分数：10.00）(1

36、).A. rotation B. switch C. management D. transmission（分数：2.00）A.B.C. D.解析：(2).A. path B. object C. route D. packet（分数：2.00）A.B. C.D.解析：(3).A. connection B. window C. module D. destination（分数：2.00）A.B.C. D.解析：(4).A. packets B. searches C. states D. instances（分数：2.00）A.B.C.D. 解析：(5).A. device B. state

37、 C. type D. packet（分数：2.00）A.B.C. D.解析：We have already covered the topic of network addresses. The first _ in a block (in class A, B, and C) defines the network address. In classes A, B, and C, if the hosted is all 1 s, the addressis called a direct broadcast address. It is used by a _ to send a pac

38、ket to all hosts in a specificnetwork. All hosts will accept a packet having this type of destination address. Note that thisaddress can be used only as a _ address in an IP packet. Note also that this special addressalso reduces the number if available hosted for each netid in classes A, B, and C.I

39、n classes A, B, and C, an address with all 1 s for the netid and hosted (32 bits) define a _ address in the current network. A host that wants to send a message to every other hosts can use this address as destinationaddress in an IP packet. However, a router will block a packet having this type of

40、address to confine thebroadcasting to the _ network. Note that this address belongs to class E.（分数：10.00）(1).A. datagram B. function C. address D. service（分数：2.00）A.B.C. D.解析：解析 我们已经讲述了有关网络地址的内容。第一种块地址(A 类、B 类和 C 类)定义了网络地址。在 A 类、B 类和 C 类地址中，如果主机 ID 部分都是“1”，这种地址叫作直接广播地址。通常被路由器用于把分组发送给某特定网络中的所有主机。所有主机

41、都接收具有这种目标地址的分组。值得注意的是，这种地址只能在 IP 分组中被用作目标地址。此外，这种特殊地址也减少了每一个 A 类、B 类和 C 类网络 ID中可用的主机 ID 数量。在 A 类、B 类和 C 类地址中，如果所有网络 ID 和主机 ID 部分(32 位)全为“1”，则这种地址定义了当前网络中的广播地址。一个主机如果想要发送报文给每一个其他主机，则可以使用这个地址作为 IP 分组的目标地址。然而，路由器通常会阻挡具有这种地址的分组，以限制向本地网络的广播。注意，这类地址属于 E 类地址。(2).A. router B. switch C. hub D. firewall（分数：2.

42、00）A. B.C.D.解析：(3).A. source B. destination C. local D. remote（分数：2.00）A.B. C.D.解析：(4).A. unicast B. multicast C. broadcast D. anycast（分数：2.00）A.B.C. D.解析：(5).A. neighbor B. next C. remote D. local（分数：2.00）A.B.C.D. 解析：One of the main responsibilities of ICMP is to report _. Although technology has p

43、roduced increasingly reliable transmission media, errors still exist and must be handled. IP is an _ protocol. This means that error checking and error control are not a concem ofIP JCMP wasdesigned, in part, to compensate for this shortcoming. Howerver, ICMP does not _ errors, itsimply reports them

44、. Error correction is left to the higher-level protocols. Error messages arealways sent to the original _ because the only information available in the datagram aboutthe route is the source and destination 1P addresses. ICMP uses the source IP address to send theerror massage to the source of the _.

45、（分数：10.00）(1).A. numbers B. functions C. strings D. Errors（分数：2.00）A.B.C.D. 解析：解析 ICMP 的其中一项职责是报告错误，虽然技术导致了日益可靠的传输介质，但是错误依然存在并需要小心处理。IP 协议是一个不可靠的协议。这意味着错误检查和错误控制不是 IP 协议的关注焦点。ICMP 的设计是为了部分地弥补这一不足。然而，ICMP 不纠正错误，仅仅报告错误。纠错通常是留给更高层的协议。错误消息总是发送到原始的来源，因为数据报中关于路由唯一可用的信息是源 IP 地址和目的IP 地址。ICMP 使用源 IP 地址来发送错误信

46、息到数据报的源地址。(2).A. reliable B. unreliable C. available D. Unavailable（分数：2.00）A.B. C.D.解析：(3).A. correct B. conduct C. produce D. Connect（分数：2.00）A. B.C.D.解析：(4).Auser Bdestination Csource DProgram（分数：2.00）A.B.C. D.解析：(5).Adatagram Bframe Cservice DProtocol（分数：2.00）A. B.C.D.解析：The presentation layer i

47、s concerned with the _ and semantics of the information exchanged between two systems. The processes in two systems are usually exchanginginformation in the form of character _, numbers, and so on. The information should bechanged to bit _ before being transmitted. Because different encoding systems

48、, thepresentation layer is responsible for _ between these different encoding methods. Thepresentation layer at the sender changes the information from its sender-dependent format into acommon format. The presentation layer at the receiving machine changes the common format intoits _ dependent format.（分数：10.00）(1).A. frequency B. syntax C. dialog D. format（分数：2.00）A.B. C.D.解析：解析 表示层关注两个系统之间信息交换的语法和语义。两个系统中通常是以字符串和数字等形式交换信息。传输前必须将信息转换成比特流。因为在不同的编码系统中，表示层负责这些不同的编码方式之间的互操作性。在发送端的表示层把信息的发送者相关格式转换为通用格式。在接收机