● 802.11标准定义了3种物理层通信技术，这3种技术不包括（62）。

试卷相关题目

• 1● 关于OSPF协议，下面的描述中不正确的是（61）。

  A.OSPF是一种链路状态协议

  B.OSPF使用链路状态公告（LSA）扩散路由信息

  C.OSPF网络中用区域1来表示主干网段

  D.OSPF路由器中可以配置多个路由进程

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• 2● 相同屏幕尺寸的显示器，点距为（60）的分辨率较高，显示图形较清晰。

  A.0.24mm

  B.0.25mm

  C.0.27mm

  D.0.28mm

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• 3● 传输一幅分辨率为640×480，6.5万色的照片（图像），假设采用数据传输速度为56kb/s.大约需要（59）秒钟。

  A.34.82

  B.42.86

  C.85.71

  D.87.77

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• 4● 按照国际电话电报咨询委员会CCITT的定义，（58）属于表现媒体。

  A.图象

  B.编码

  C.硬盘

  D.扫描仪

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• 5● RGB4:4:2表示一幅彩色图像可生成的颜色数是 (57) 种。

  A.256

  B.1024

  C.4096

  D.65536

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• 6● 关于Windows操作系统中DHCP服务器的租约，下列说法中错误的是（63）。

  A.默认租约期是8大

  B.客户机一直使用DHCP服务器分配给它的IP地址，直至整个租约期结束才开始联系更新租约

  C.当租约期过了一半时，客户机将与提供IP地址的DHCP服务器联系更新租约

  D.在当前租约期过去87.5%时，如果客户机与提供IP地址的DHCP服务器联系不成功，则重新开始IP租用过程

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• 7● 确定网络的层次结构及各层采用的协议是网络设计中（64）阶段的主要任务。

  A.网络需求分析

  B.网络体系结构设计

  C.网络设备选型

  D.网络安全性设计

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• 8● 在IPv4中，组播地址是（65）地址。

  A.A类

  B.B类

  C.C类

  D.D类

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• 9● WLANs are increasingly popular because they enable cost-effective connections among people，applications and data that were not possible，or not cost-effective, in the past. For example, WLAN-based applications can enable fine-grained management of supply and distribution （66） to improve their efficienty and reduce （67） . WLANs can also enable entirely new business processes．To cite but one example, hospitals are using WLAN-enabled point-of-care applications to reduce errors and improve overall（68）care．WLAN management solutions provide a variety of other benefits that can be substantial but difficult to measure. For example, they can protect corporate data by preventing（69）through rogue access points. They help control salary costs, by allowing IT staffs to manage larger networks without adding staff. And they can improve overall network mananement by integrating with customers' existing systems, such as OpenView and UniCenter. Fortunately, it isn’t necessary to measure these benefits to justify investing in    WLAN management solutions，which can quickly pav for themselves simolv by minimizinu time-consunlina（70）and administrative chores.

  A.chores

  B.chains

  C.changes

  D.links

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• 10● To compete in today's fast-paced competitive environment, organizations are increasingly allowing contractors, partners, visitors and guests to access their internal enterprise networks．These users may connect to the network through wired ports in conference rooms or offices, or via wireless access points．in allowing this open access for third parties, LANs become（71）. Third parties can introduce risk in a variety of ways from connecting with an infected laptop to unauthorized access of network resources to （72） activity. For many organizations,however, the operational complexity and costs to ensure safe third party network access have been prohibitive. Fifty-two percent of surveyed CISOs state that they currently use a moat and castle's security approach, and admit that defenses inside the perimeter are weak. Threats from internal users are also increasingly a cause for security concerns．Employees with malicious intent can launch（73）of service attacks or steal（74）information by snooping the network. As they access the corporate network, mobile and remote users inadvertently can infect the network with （75） and worms acquired from unprotected public networks．Hackers masquerading as internal users can take advantage of weak internal security to gain access to confidential information.

  A.damageable

  B.susceptible

  C.vulnerable

  D.changeable

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