第5章以太网1下列有关MAC地址的说法中哪一项正确？MAC地址由软件实施。
如果连接到WAN，网卡只需要MAC地址。
前三个字节用于供应商分配的OUI。
ISO负责MAC地址规范。
一个MAC地址包含6个字节。
前3个字节用于供应商标识，最后3个字节必须在同一OUI中分配唯一的值。
MAC地址在硬件中实施。
网卡需要使用MAC地址来通过LAN通信。
IEEE规范了MAC地址。
答案说明最高分值correctness of response 2points for Option30points for any other option22下列哪项是争用访问方法的特征？它比受控访问方法处理更多开销。
它具有跟踪介质访问次序的机制。
它属于非确定性方法。
它在介质使用率高的情况下能够轻松扩展。
争用方法具有不确定性，没有受控访问方法中遇到的开销。
因为设备不需要轮流访问介质，所以无需跟踪次序。
争用方法在介质使用率高的情况下无法很好地扩展。
答案说明最高分值correctness of response2points for Option30points for any other option23下列哪两种说法正确描述了以太网标准中逻辑链路控制子层的特点或功能？（请选择两项。
）逻辑链路控制在软件中实现。
逻辑链路控制在IEEE802.3标准中指定。
LLC子层直接与网卡驱动程序软件进行交互。
数据链路层使用LLC与协议簇的上层通信。
LLC子层负责定位和检索介质上和介质外的帧。
逻辑链路控制在软件中实施，能够让数据链路层与协议簇的上层协议通信。
网卡驱动程序软件直接与网卡上的硬件交互，可在MAC子层和物理介质之间传输数据。
逻辑链路控制在IEEE802.2标准中指定。
IEEE802.3是定义不同以太网类型的一组标准。
MAC（介质访问控制）子层负责定位和检索介质上和介质外的帧。
答案说明最高分值correctness of response Option1and Option4are correct.1point for each correct option.0points if more options are selected than required.24以太网帧中的前导码有何作用？作为数据的填充位用于同步计时用于标识源地址。
计算机类十大含金量证书考试时间近年来，计算机技术的飞速发展给求职竞争带来了新的挑战。
拥有一项含金量高的计算机类证书不仅可以增加求职竞争力，更有助于提升职业发展。
下面将介绍计算机类十大含金量证书的考试时间安排。
1. Cisco CCNA•考试时间：每天均可考试，预约时间灵活。
2. CompTIA A+•考试时间：建议提前预约，根据考试中心时间安排。
3. CEH（Certified Ethical Hacker）•考试时间：根据具体考试安排，一般在工作日进行。
4. AWS Certified Solutions Architect•考试时间：根据考试安排，可在全球各大考试中心进行考试。
5. PMP（Project Management Professional）•考试时间：需提前预约，根据考试中心时间安排。
6. ITIL Foundation•考试时间：根据考试安排，一般在工作日进行。
7. Microsoft Certified Solutions Expert (MCSE)•考试时间：建议提前预约，根据考试中心时间安排。
8. CISSP（Certified Information Systems Security Professional）•考试时间：根据具体考试安排，一般在工作日进行。
9. Google Certified Professional Cloud Architect•考试时间：需提前预约，具体时间安排根据考试中心而定。
10. VMware Certified Professional•考试时间：根据考试安排，可在全球各大考试中心进行考试。
不同的证书考试时间安排各有不同，建议考生根据自身时间和计划提前进行合理安排，并及时关注官方网站或考试中心的最新通知。
只有做好充分的准备和灵活的考试安排，才能顺利通过这些含金量高的计算机类证书考试，为自己的职业发展增添新的动力。
1对网络电缆采用的连接器不正确可能产生什么后果？会将数据转发到错误的节点。
通过该电缆传输的数据可能发生信号丢失。
将对该电缆中传输的数据采用不正确的信号方法。
该电缆中发送的数据所采用的编码方法将更改，用于补偿不当连接。
2大多数企业LAN 中的双绞线网络电缆使用哪种连接器？BNCRJ-11RJ-45F 型3在网络中传输数据时，物理层的主要作用是什么？创建信号以表示介质上每个帧中的比特为设备提供物理编址确定数据包的网络通路控制数据对介质的访问4数据传输的三种量度标准是什么？（选择三项）实际吞吐量频率幅度吞吐量串扰带宽5UTP 电缆的哪个特征有助于减少干扰的影响？屏蔽层中的金属编织包裹核心的反射涂层电缆中的线对绕绞外皮中的绝缘材料6XYZ 公司正在其数据网络中安装新的电缆。
下列哪两种类型是新架设时最常用的电缆？（选择两项）同轴4 类UTP5 类UTP6 类UTPSTP7使用什么设备可以检查安装的光纤是否存在错误并检查其完整性和介质性能？光注入器OTDRTDR万用表8以下哪项是单模光缆的特征？一般使用LED 作为光源因为有多条光通路，核心相对较粗价格比多模低一般使用激光作为光源9请参见图示。
哪种 5 类电缆用于在主机 A 和主机 B 之间建立以太网连接？同轴电缆全反电缆交叉电缆直通电缆10以下哪项被视为选择无线介质的优点？主机移动更方便安全风险更低减少干扰的影响环境对有效覆盖面积的影响更小11如果在网络中使用非屏蔽双绞线铜缆，导致线对内串扰的原因是什么？相邻线对周围的磁场使用编织线屏蔽相邻线对从电缆远端反射回来的电波因两个节点尝试同时使用介质而导致的冲突12哪种光纤连接器支持全双工以太网？13哪种电缆通常与光缆相关联？主干电缆水平电缆跳线电缆工作区域电缆14在可能存在电气危险或电磁干扰的LAN 安装中，主干布线建议使用哪种类型的介质？同轴光纤5e 类UTP6 类UTP15网络中什么时候使用直通电缆？通过控制台端口连接路由器时连接两台交换机时连接主机与交换机时连接两台路由器时16以下哪些特征描述的是光缆？（选择两项）不受 EMI 或RF I 影响。
ENetwork Chapter 5 - CCNA Exploration: Network Posted by Space on Sunday, May 10, 20091In an IPv4 environment, what information is used by the router to forward data packets from one interface of a router to another?**destination network addresssource network addresssource MAC addresswell known port destination address2What information is added during encapsulation at OSI Layer 3?source and destination MACsource and destination application protocolsource and destination port number**source and destination IP address3In a connectionless system, which of the following is correct?The destination is contacted before a packet is sent.**The destination is not contacted before a packet is sent.The destination sends an acknowledgement to the source that indicates the packet was received. The destination sends an acknowledgement to the source that requests the next packet to be sent.4Which IP packet field will prevent endless loops?type-of-serviceidentificationflags**time-to-liveheader checksum5Which portion of the network layer address does a router use to forward packets?host portionbroadcast address**network portiongateway address6Refer to the exhibit. Using the network in the exhibit, what would be the default gateway address for host A in the 192.133.219.0 network?192.135.250.1192.31.7.1192.133.219.0**192.133.219.17If the default gateway is configured incorrectly on the host, what is the impact on communications? The host is unable to communicate on the local network.**The host can communicate with other hosts on the local network, but is unable to communicate with hosts on remote networks.The host can communicate with other hosts on remote networks, but is unable to communicate with hosts on the local network.There is no impact on communications.8What is the purpose of a default gateway?physically connects a computer to a networkprovides a permanent address to a computeridentifies the network to which a computer is connectedidentifies the logical address of a networked computer and uniquely identifies it to the rest of the network**identifies the device that allows local network computers to communicate with devices on other networks9What type of routing uses information that is manually entered into the routing table?dynamicinterior**staticstandard10When the destination network is not listed in the routing table of a Cisco router, what are two possible actions that the router might take? (Choose two.)The router sends an ARP request to determine the required next hop address.**The router discards the packet.The router forwards the packet toward the next hop indicated in the ARP table.The router forwards the packet to the interface indicated by the source address.**The router forwards the packet out the interface indicated by the default route entry.11What are the key factors to consider when grouping hosts into a common network? (Choose three.) gateways**purposephysical addressingsoftware version**geographic location**ownership12What is a component of a routing table entry?the MAC address of the interface of the routerthe destination Layer 4 port numberthe destination host address**the next-hop address13Which intermediary devices could be used to implement security between networks? (Choose two.) **routerhubswitch**firewallaccess pointbridge14What are three common problems with a large network? (Choose three.)too few broadcasts**performance degradation**security issueslimited management responsibility**host identificationprotocol compatibility15Refer to the exhibit. All devices shown in the exhibit have factory default settings. How many broadcast domains are represented in the topology that is shown?3**45781116Which three statements are true about routes and their use? (Choose three.)If no route to the destination network is found, the packet is returned to the previous router.**If the destination network is directly connected, the router forwards the packet to the destination host.If multiple network entries exist for the destination network, the most general route is used to forward the packet.**If no route exists for the destination network and a default route is present, the packet is forwarded to the next-hop router.**If the originating host has a default gateway configured, the packet for a remote network can beforwarded using that route.If a host does not have a route manually configured for the destination network, the host will drop the packet.17Refer to the exhibit. A network administrator is troubleshooting a connectivity problem and needs to determine the address that is used to forward network packets out the network. Using the netstat -r command, the administrator would identify which address as the address to which all hosts send packets that are destined for an outside network?10.10.10.26127.0.0.1**10.10.10.610.10.10.1224.0.0.018Refer to the exhibit. A network administrator notices that there are too many broadcasts on the network. What two steps can the network administrator take to resolve this problem? (Choose two.) **Replace S2 with a router.Place all servers on S1.Disable TCP/IP broadcasts.**Subnet the 192.168.0.0 /24 network.Disable all unused interfaces on the switches.19Refer to the exhibit. The network in the exhibit is fully operational. What two statements correctly describe the routing for the topology that is shown? (Choose two.)**192.168.0.2 is the next-hop address that is used by R3 to route a packet from the 10.0.0.0 network to the 172.16.0.0 network.10.0.0.1 is the next-hop address that is used by R1 to route a packet from the 192.168.12.0 network to the 10.0.0.0 network.192.168.0.1 is the next-hop address that is used by R1 to route a packet from the 192.168.12.0 network to the 172.16.0.0 network.172.16.0.1 is the next-hop address that is used by R3 to route a packet from the 10.0.0.0 to the 172.16.0.0 network.**192.168.0.1 is the next-hop address that is used by R2 to route a packet from the 172.16.0.0 network to the 192.168.12.0 network.192.168.0.2 is the next-hop address that is used by R2 to route a packet from the 172.16.0.0 network to the 192.168.12.0 network.20What two characteristics are commonly associated with dynamic routing protocols? (Choose two.) require no device configuration**provide routers with up-to-date routing tablesrequire less processing power than static routes require**consume bandwidth to exchange route informationprevent manual configuration and maintenance of the routing table21What statement describes the purpose of a default route?A host uses a default route to transfer data to another host on the same network segment.A host uses a default route to forward data to the local switch as the next hop to all destinations.A host uses a default route to identify the Layer 2 address of an end device on the local network. **A host uses a default route to transfer data to a host outside the local network when no other route to the destination exists.。
