200401_wlgcs_1.htm

参加全国网络工程师考试的参考资料

lang=EN-US>__(5)__</span>两部分。<span lang=EN-US><br>
</span>　　<span lang=EN-US>(1)A</span>．建立和释放连接<span class=GramE>　　　　　　</span><span
lang=EN-US>B</span>．透明地传输比特流<span lang=EN-US><br>
</span>　　<span class=GramE>　</span><span lang=EN-US> C</span>．在物理实体间传送数据帧　　<span
lang=EN-US>D</span>．发送和接收用户数据<span lang=EN-US><br>
</span>　　<span lang=EN-US>(2)A</span>．接口数据单元<span class=GramE>　　　　　　　</span><span
lang=EN-US>B</span>．服务数据单元<span lang=EN-US><br>
</span>　　<span class=GramE>　</span><span lang=EN-US> C</span>．协议数据单元<span
class=GramE>　　　　　　　</span><span lang=EN-US>D</span>．交互数据单元<span lang=EN-US><br>
</span>　　<span lang=EN-US>(3)A</span>．控制信息和用户数据<span class=GramE>　　　　</span><span
lang=EN-US>B</span>．接口信息和用户数据<span lang=EN-US><br>
</span>　　<span class=GramE>　</span><span lang=EN-US> C</span>．接口信息和控制信息<span
class=GramE>　　　　</span><span lang=EN-US>D</span>．控制信息和校验信息<span lang=EN-US><br>
</span>　　<span lang=EN-US>(4)A</span>．用户地址　　<span lang=EN-US>B</span>．网络地址　<span
lang=EN-US> C</span>．端口地址　　<span lang=EN-US>D</span>．网卡地址<span lang=EN-US><br>
</span>　　<span lang=EN-US>(5)A</span>．网络号和端口号<span class=GramE>　　　　　　</span><span
lang=EN-US>B</span>．网络号和主机地址<span lang=EN-US><br>
</span>　　<span class=GramE>　</span><span lang=EN-US> C</span>．超网号和子网号<span
class=GramE>　　　　　　</span><span lang=EN-US>D</span>．超网号和端口地址 </span><span
lang=EN-US style='mso-bidi-font-size:10.5pt;color:white'>(</span><span
style='mso-bidi-font-size:10.5pt;color:white'>此括号内不是试题部分。欢迎访问软件考试网<span
lang=EN-US>www.hbsoft.net)</span></span><span lang=EN-US style='font-size:10.5pt;
color:black'><o:p></o:p></span></p>

<p><span style='font-size:10.5pt;color:black'>　　<span lang=EN-US>●</span>物理层的电气特性有多种标准，其中<span
lang=EN-US>CCITT</span>的<span lang=EN-US>V.11</span>建议中规定<span lang=EN-US>__(6)__</span>。常用的<span
lang=EN-US>EIA RS-232</span>接口的电气特性与<span lang=EN-US>CCITT</span>的<span
lang=EN-US>__(7)__</span>兼容，在这种电路中，数据<span lang=EN-US>“1”</span>的接口电平规定为<span
lang=EN-US>__(8)__</span>。在<span lang=EN-US>RS-232</span>定义的接口线中，<span
lang=EN-US>__(9)__</span>表示计算机请求发送数据，<span lang=EN-US>__(10)__</span>表示计算机准备接收数据。<span
lang=EN-US><br>
</span>　　<span lang=EN-US>(6)A</span>．发送器采用非平衡方式工作，接收器采用平衡方式工作<span lang=EN-US><br>
</span>　　<span class=GramE>　</span><span lang=EN-US> B</span>．发送器采用平衡方式工作，接收器采用非平衡方式工作<span
lang=EN-US><br>
</span>　　<span class=GramE>　</span><span lang=EN-US> C</span>．发送器和接收器都采用非平衡方式工作<span
lang=EN-US><br>
</span>　　<span class=GramE>　</span><span lang=EN-US> D</span>．发送器和接收器都采用平衡方式工作<span
lang=EN-US><br>
</span>　　<span lang=EN-US>(7)A</span>．<span lang=EN-US>V.10</span>　　<span
class=GramE>　</span><span lang=EN-US> B</span>．<span lang=EN-US>V.11</span><span
class=GramE>　　　　</span><span lang=EN-US>C</span>．<span lang=EN-US>V.24</span><span
class=GramE>　　　　</span><span lang=EN-US>D</span>．<span lang=EN-US>V.28<br>
</span>　　<span lang=EN-US>(8)A</span>．<span lang=EN-US>-3</span>～<span
lang=EN-US>-15V</span>　<span lang=EN-US> B</span>．<span lang=EN-US>+3</span>～<span
lang=EN-US>+15V</span>　　<span lang=EN-US>C</span>．<span lang=EN-US>+5</span>～<span
lang=EN-US>+15V</span>　　<span lang=EN-US>D</span>．<span lang=EN-US>-5</span>～<span
lang=EN-US>-15V<br>
</span>　　<span lang=EN-US>(9)A</span>．<span lang=EN-US>DCD</span><span
class=GramE>　　　　</span><span lang=EN-US>B</span>．<span lang=EN-US>TD</span><span
class=GramE>　　　　　</span><span lang=EN-US>C</span>．<span lang=EN-US>RTS</span><span
class=GramE>　　　　</span><span lang=EN-US> D</span>．<span lang=EN-US>DSR<br>
</span>　　<span lang=EN-US>(10)A</span>．<span lang=EN-US>CTS</span>　　<span
class=GramE>　</span><span lang=EN-US> B</span>．<span lang=EN-US>DTR</span><span
class=GramE>　　　　</span><span lang=EN-US> C</span>．<span lang=EN-US>RD</span><span
class=GramE>　　　　　</span><span lang=EN-US>D</span>．<span lang=EN-US>RI <o:p></o:p></span></span></p>

<p><span style='font-size:10.5pt;color:black'>　　<span lang=EN-US>●</span>非对称数字用户线<span
lang=EN-US>ADSL</span>是采用<span lang=EN-US>__(11)__</span>调制通过双绞线向用户提供宽带业务、交互式数据业务和普通电话服务的接入技术，其上行速率为<span
lang=EN-US>640Kb/s</span>～<span lang=EN-US>1Mb/s</span>，下行速率为<span lang=EN-US>1Mb/s</span>～<span
lang=EN-US>__(12)__</span>，有效传输距离为<span lang=EN-US>3</span>～<span lang=EN-US>5</span>公里。<span
lang=EN-US>ADSL</span>接入互联网的两种方式是：<span lang=EN-US>__(13)__</span>。<span
lang=EN-US><br>
</span>　　<span class=SpellE><span lang=EN-US>CableModem</span></span>又叫线缆调制解调器，它可以连接用户家中的<span
lang=EN-US>PC</span>机和<span lang=EN-US>__(14)__</span>网络。<span lang=EN-US>Cable
Modem</span>的最高上行速率可达<span lang=EN-US>__(15)__</span>，下行速率则更高，彻底解决了由于声音<span
lang=EN-US>/</span>图像传输而引起的阻塞。<span lang=EN-US><br>
</span>　　<span lang=EN-US>(11)A</span>．<span lang=EN-US>TDM</span>　　<span
class=GramE>　</span><span lang=EN-US> B</span>，<span lang=EN-US>FDM</span><span
class=GramE>　　　　</span><span lang=EN-US> C</span>．<span lang=EN-US>WDM</span><span
class=GramE>　　　　</span><span lang=EN-US> D</span>．<span lang=EN-US>CDM<br>
</span>　　<span lang=EN-US>(12)A</span>．<span lang=EN-US>8Mb/s</span>　　<span
lang=EN-US> B</span>．<span lang=EN-US>4Mb/s</span>　　<span class=GramE>　</span><span
lang=EN-US> C</span>．<span lang=EN-US>2Mb/s</span>　　<span class=GramE>　</span><span
lang=EN-US> D</span>．<span lang=EN-US>1.5Mb/s<br>
</span>　　<span lang=EN-US>(13)A</span>．固定接入和虚拟拨号　　<span class=GramE>　</span><span
lang=EN-US> B</span>．专线接入和<span lang=EN-US>VLAN</span>接入<span lang=EN-US><br>
</span><span class=GramE>　　　　</span><span lang=EN-US>C</span>．固定接入和<span
lang=EN-US>VLAN</span>接入　　<span class=GramE>　</span><span lang=EN-US> D</span>．专线接入和虚拟拨号<span
lang=EN-US><br>
</span>　　<span lang=EN-US>(14)A</span>．<span lang=EN-US>ATM</span>　　<span
class=GramE>　</span><span lang=EN-US> B</span>．<span lang=EN-US>PSTN</span><span
class=GramE>　　　　</span><span lang=EN-US>C</span>．<span lang=EN-US>HFC</span><span
class=GramE>　　　　</span><span lang=EN-US> D</span>．<span lang=EN-US>FRN<br>
</span>　　<span lang=EN-US>(15)A</span>．<span lang=EN-US>10Mb/s</span>　　<span
lang=EN-US>B</span>．<span lang=EN-US>2Mb/s</span>　　<span class=GramE>　</span><span
lang=EN-US> C</span>．<span lang=EN-US>1.5Mb/s</span>　　<span lang=EN-US> D</span>．<span
lang=EN-US>1Mb/s <o:p></o:p></span></span></p>

<p><span style='font-size:10.5pt;color:black'>　　<span lang=EN-US>●</span>码是一些码字组成的集合。一对码字之间的海明距离是<span
lang=EN-US>__(16)__</span>，一个码的海明距离是所有不同码字的海明距离的<span lang=EN-US>__(17)__</span>。如果要检查出<span
lang=EN-US>d</span>位错，那么码的海明距离是<span lang=EN-US>__(1)__</span>。如果信息长度为<span
lang=EN-US>5</span>位，要求纠正<span lang=EN-US>1</span>位错，按照海明编码，需要增加的校验位是<span
lang=EN-US>__(19)__</span>。以太网中使用的校验<span class=GramE>码标准</span>是<span
lang=EN-US>__(20)__</span>。<span lang=EN-US><br>
</span>　　<span lang=EN-US>(16)A</span>．码字之间不同的位数　　<span class=GramE>　</span><span
lang=EN-US> B</span>．两个码字之间相同的位数<span lang=EN-US><br>
</span><span class=GramE>　　　　</span><span lang=EN-US>C</span>．两个码字的校验和之和　　<span
lang=EN-US> D</span>．两个码字的校验和之差<span lang=EN-US><br>
</span>　　<span lang=EN-US>(17)A</span>．平均值　　<span lang=EN-US>B</span>．最大值　　<span
class=GramE>　</span><span lang=EN-US>C</span>．最小值　　<span class=GramE>　</span><span
lang=EN-US>D</span>．任意值<span lang=EN-US><br>
</span>　　<span lang=EN-US>(18)A</span>．<span lang=EN-US>d-1</span>　　<span
class=GramE>　</span><span lang=EN-US> B</span>．<span lang=EN-US>d+1</span><span
class=GramE>　　　　</span><span lang=EN-US> C</span>．<span lang=EN-US>2d-1</span><span
class=GramE>　　　　</span><span lang=EN-US>D</span>．<span lang=EN-US>2d+l<br>
</span>　　<span lang=EN-US>(19)A</span>．<span lang=EN-US>3</span><span
class=GramE>　　　　</span><span lang=EN-US> B</span>．<span lang=EN-US>4</span><span
class=GramE>　　　　　</span><span lang=EN-US> C</span>．<span lang=EN-US>5</span><span
class=GramE>　　　　　</span><span lang=EN-US> D</span>．<span lang=EN-US>6<br>
</span>　　<span lang=EN-US>(20)A</span>．<span lang=EN-US>CRC-12</span>　　<span
lang=EN-US>B</span>．<span lang=EN-US>CRC-CCITT</span>　<span lang=EN-US> C</span>．<span
lang=EN-US>CRC-16</span>　　<span class=GramE>　</span><span lang=EN-US>D</span>．<span
lang=EN-US>CRC-32 </span></span><span lang=EN-US style='mso-bidi-font-size:
10.5pt;color:white'>(</span><span style='mso-bidi-font-size:10.5pt;color:white'>此括号内不是试题部分。欢迎访问软件考试网<span
lang=EN-US>www.hbsoft.net)</span></span><span lang=EN-US style='font-size:10.5pt;
color:black'><o:p></o:p></span></p>

<p><span style='font-size:10.5pt;color:black'>　　<span lang=EN-US>●ATM</span>网络的协议数据单元称为<span
lang=EN-US>__(21)__</span>。<span lang=EN-US>ATM</span>适配<span class=GramE>层分为</span>两个子层，这两个子层是<span
lang=EN-US>__(22)__</span>子层。<span lang=EN-US>__(23)__</span>是对应于<span
lang=EN-US>A</span>类业务的<span lang=EN-US>ATM</span>适配层，它提供的业务特点是<span
lang=EN-US>__(24)__</span>。如果要传送<span lang=EN-US>IP</span>数据报，则需要<span
lang=EN-US>__(25)__</span>业务的支持。<span lang=EN-US><br>
</span>　　<span lang=EN-US>(21)A</span>．<span class=GramE>帧　　　　</span><span
lang=EN-US>B</span>．信元<span class=GramE>　　　　</span><span lang=EN-US>C</span>．分组<span
class=GramE>　　　　</span><span lang=EN-US>D</span>，报文<span lang=EN-US><br>
</span>　　<span lang=EN-US>(22)A</span>．<span lang=EN-US>PMD</span>和<span
lang=EN-US>TC</span>　<span lang=EN-US> B</span>．<span lang=EN-US>PMD</span>和<span
lang=EN-US>SAR</span>　　<span lang=EN-US>C</span>．<span lang=EN-US>CS</span>和<span
lang=EN-US>SAR</span>　　<span lang=EN-US> D</span>．<span lang=EN-US>CS</span>和<span
lang=EN-US>TC<br>
</span>　　<span lang=EN-US>(23)A</span>．<span lang=EN-US>AALI</span>　　<span
class=GramE>　</span><span lang=EN-US>B</span>．<span lang=EN-US>AAL2</span><span
class=GramE>　　　　</span><span lang=EN-US>C</span>．<span lang=EN-US>AAL3</span><span
class=GramE>　　　　</span><span lang=EN-US>D</span>．<span lang=EN-US>AAL4<br>
</span>　　<span lang=EN-US>(24)A</span>．实时、恒定比特率、面向连接　<span lang=EN-US> B</span>．实时、可变比特率、面向连接<span
lang=EN-US><br>
</span><span class=GramE>　　　　</span><span lang=EN-US>C</span>．非实时、恒定比特率、无连接　<span
lang=EN-US> D</span>．非实时、恒定比特率、面向连接<span lang=EN-US><br>
</span>　　<span lang=EN-US>(25)A</span>，<span lang=EN-US>A</span>类　　<span
class=GramE>　</span><span lang=EN-US> B</span>．<span lang=EN-US>B</span>类<span
class=GramE>　　　　</span><span lang=EN-US> C</span>．<span lang=EN-US>C</span>类<span
class=GramE>　　　　</span><span lang=EN-US> D</span>．<span lang=EN-US>D</span>类<span
lang=EN-US> <o:p></o:p></span></span></p>

<p><span style='font-size:10.5pt;color:black'>　　<span lang=EN-US>●</span>动态主机配置协议<span
lang=EN-US>DHCP</span>是对<span lang=EN-US>BOOTP</span>协议的扩充，<span lang=EN-US>DHCP</span>与<span
lang=EN-US>BOOTP</span>的主要区别是<span lang=EN-US>DHCP</span>具有<span lang=EN-US>__(26)__</span>机制。<span
lang=EN-US>DHCP</span>协议支持的中继代理<span lang=EN-US>(Relay Agent)</span>是一种<span
lang=EN-US>__(27)__</span>，它可以在不同的网段之间传送报文。<span lang=EN-US>DHCP</span>具有多种地址分配方案，对于移动终端<span
lang=EN-US>(</span>比如笔记本电脑<span lang=EN-US>)</span>最适合的分配方案是<span lang=EN-US>__(28)__</span>。使用<span
lang=EN-US>Windows2000</span>操作系统的<span lang=EN-US>DHCP</span>客户机，如果启动时无法与<span
lang=EN-US>DHCP</span>服务器通信，它将<span lang=EN-US>__(29)__</span>因为<span
lang=EN-US>DHCP</span>报文是装入<span lang=EN-US>__(30)__</span>协议数据单元中传送的，所以它是不安全的。<span
lang=EN-US><br>
</span>　　<span lang=EN-US>(26)A</span>．动态地址绑定和租约　　<span class=GramE>　</span><span
lang=EN-US> B</span>．报文扩充<span lang=EN-US><br>
</span><span class=GramE>　　　　</span><span lang=EN-US>C</span>．配置参数提交<span
class=GramE>　　　　　　</span><span lang=EN-US> D</span>．中继代理<span lang=EN-US><br>
</span>　　<span lang=EN-US>(27)A</span>．使用<span lang=EN-US>DHCP</span>协议的路由器　　<span
lang=EN-US> B</span>．转发<span lang=EN-US>DHCP</span>报文的主机或路由器<span lang=EN-US><br>