● Networks can be interconnected by different devices. In the physical layer, networkscan be connected by （66） or hubs, which just move the bits from one network to anidentical network. One layer up we find bridges and switches, which operate at datalink layer. They can accept （67） , examine the MAC address, and forward the framesto a different network while doing minor protocol translation in the process. In thenetwork layer, we have routers that can connect two networks. 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 twotransport connections. Finally, in the application layer, application gatewaystranslate message （69） . As an example, gateways between Internet e-mail and X.400e-mail must （70） the e-mail message and change various header fields.

试卷相关题目

• 1● 以下不属于中间件技术的是 （65） 。

  A.Java RMI

  B.CORBA

  C.DCOM

  D.Java Applet

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• 2● 将双绞线制作成交叉线（一端按EIA/TIA 568A线序，另一端按EIA/TIA 568B线序），该双绞线连接的两个设备可为 （64） 。

  A.网卡与网卡

  B.网卡与交换机

  C.网卡与集线器

  D.交换机的以太口与下一级交换机的UPLINK口

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• 3● 许多网络通信需要进行组播，以下选项中不采用组播协议的应用是 （62） 。在IPv4中把（63） 类地址作为组播地址。

  A.VOD

  B.Netmeeting

  C.CSCW

  D.FTP

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• 4● 以太网100BASE-TX标准规定的传输介质是 （61） 。

  A.3类UTP

  B.5类UTP

  C.单模光纤

  D.多模光纤

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• 5● 下面描述正确的是 （60） 。

  A.数据仓库是从数据库中导入大量的数据，并对结构和存储进行组织以提高查询效率

  B.使用数据仓库的目的在于对已有数据进行高速的汇总和统计

  C.数据挖掘是采用适当的算法，从数据仓库的海量数据中提取中潜在的信息和知识

  D.OLAP技术为提高处理效率，必须绕过DBMS直接对物理数据进行读取和写入

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• 6●  The purpose of the requirements definition phase is to produce a clear, complete,consistent, and testable （71） of the technical requirements for the software product.During the requirements definition phase, the requirements definition team uses aniterative process to expand a broad statement of the system requirements into a completeand detailed specification of each function that the software must perform and each（72） that it must meet. The starting point is usually a set of high-level requirementsfrom the （73） that describe the project or problem.    In either case, the requirements definition team formulates an overall conceptfor the system and then defines （74） showing how the system will be operated, publishesthe system and operations concept document, and conducts a system concept review(SCR).Following the SCR, the team derives （75） requirements for the system from the highlevel requirements and the system and operations concept. Using structured orobject-oriented analysis, the team specifies the software functions and algorithmsneeded to satisfy each detailed requirement.

  A.function

  B.definition

  C.specification

  D.statement

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