6月份CCNA题库更新部分详解.docx

6月份CCNA题库更新部分详解1、Which three are characteristics of an IPV6 anycast address?(choose three)A.any-to-many communication modelB.delivery of packets to the group interface that is closest to the sending deviceC.one-to-many communication modelD.the same address for multiple devices in the groupE.one-to-nearest communication modelF.a unique IPV6 address for each device in the group答案 BDEA 多对多通信模型 B 数据包传送到该组接口，转发到最近的节点C 一对多通信模型D 同组中多个接口共用一个地址E 发送到任播地址的分组被转发到最近的端口（节点）F 组中每个节点有一个唯一的IV6地址（每台设备可以有一个以上的端口，所以用节点来表示）2、Which name describes an IPV6 host-enable tunneling technique that uses IPV4 UDP,does not require dedicated gateway tunnels,and can pass through existing IPV4 NAT gateways?A.dual stackB.dynamicC.TeredoD.Manual 6to4答案 CTeredo 是一项 IPv6/IPv4 转换技术，能够实现在处于单个或者多个 IPv4 NAT 后的主机之间的 IPv6 自动隧道。来自 Teredo 主机的 IPv6 数据流能够通过 NAT，因为它是以 IPv4 UDP 数据格式发送的。如果 NAT 支持 UDP 端口解析，那么它就支持 Teredo 。3、Which pairing reflects a correct protocol-and-metric relationship?A. OSPF and number of hops and reliabilityB. EIGRP and link costC. IS-IS and delay and reliabilityD. RIPv2 and number of hops答案 DA. OSPF与跳数和可靠性，实际ospf是通过接口宽带计算出花费值来度量的B. EIGRP与链路花费值，实际eigrp是以带宽、延时、负载、可靠性及MTU来度量的C. IS-IS与延迟和可靠性，实际is-is是以默认、延迟、开销、差错来度量的，主要用默认度量，相当于ospf的cost值度量D. RIPv2与跳数。RIPv2是以跳数来度量的，所以选D4、How are VTP advertisements delivered to switches across the network?A. anycast framesB. multicast framesC. broadcast framesD. unicast frames答案：B. anycast frames（任意广播帧），multicast frames（组播帧），broadcast frames（广播帧），unicast frames （单播帧）。通告将数据帧发送到一个多点广播地址（组播地址），以使所有相邻设备都能收到这些帧。5、Two switches are connected through a trunk link.which two commands show that there is a native VLAN mismatch on that link?(choose two)A. show interfaces interfaceB. show vlan briC. show interfaces interface switchportD. show interface trunkE. show interfaces vlan答案 CD题目要求能够查看到native vlan错误的例子。6、What is the result of issuing the frame-relay map ip 192.168.1.2 202 broadcast command?A. defines the source IP address that is used in all broadcast packets on DLCI 202B. defines the DLCI that is used for all packets that are sent to the 192.168.1.2 IP addressC. defines the destination IP address that is used in all broadcast packets on DLCI 202D. defines the DLCI on which packets from the 192.168.1.2 IP address are received答案 B题目是说， frame-relay map ip 192.168.1.2 202 broadcast 这条命令的作用翻译选项A source IP address，不是源IP，是目的IPB对所有发送到192.168.1.2的IP地址的数据包使用的DLCI为202的PVCC 使用广播包，不正确D从192.168.1.2接收到的数据包使用DLCI，不正确7、Which are three reasons that an organization with multiple branch offices and roaming users might implement a Cisco VPN solution instead of point-to-point WAN links?(choose three)A.reduced cost B.better throughputC.increased securityD.scalabilityE.reduced latencyF.broadband incompatibility答案：A C D. VPN为“虚拟专用网络”，被定义为通过一个公用网络（通常是因特网）建立一个临时的、安全的连接，是一条穿过混乱的公用网络的安全、稳定隧道。VPN特点：能够保证数据的私有性和安全性A 节约成本 B提高吞吐量 和链路带宽有关系C 增强安全性D 易扩展E减少潜在因素 F带宽不相容 没关系8、Which two Cisco IOS commands ,used in troubleshooting,can enable debug output to a remote location?(choose two)A.no logging consoleB.terminal monitorC.logging host ip-addressD.snmp-server enable traps syslogE.show logging | redirect flash: output.txt答案BEA用来停止向控制台发送信息B 是用来打开终端显示信息中心发送的调试/日志/告警信息功能C 指定日志到服务器D 是用来发送snmp traps 信息（snmp-server enable traps），syslog是单独配置的E 是用来查看日志重新定下文件9、Which two data intergrity algorithms are commonly used in VPN solutions?(choose two)A.HMAC-MD5B.RSAC.HMAC-SHA-1D.DH1E.DH2正确答案，选A和C：Message Digest Algorithm MD5（中文名为消息摘要算法第