CCNA第二学期练习答案chapter3
计算机网络课后答案第三章
第三章 数据链路层习题3-02 数据链路层中的链路控制包括哪些功能？答：数据链路层中的链路控制功能有：（1）链路管理。
（2）帧定界。
（3）流量控制。
（4）差错控制。
（5）将数据和控制信息区分开。
（6）透明传输。
（7）寻址。
习题3-03考察停止等待协议算法。
在接收结点，当执行步骤（4）时，若将“否则转到（7）”改为“否则转到（8）”，将产生什么结果？答：“否则”是指发送方发送的帧的N （S ）和接收方的状态变量V （R ）不同。
表明发送方没有收到接收方发出的ACK ，于是重传上次的帧。
若“转到（8）”，则接收方要发送NAK 。
发送方继续重传上次的帧，一直这样下去。
习题3-06 信道速率为4kb/s 。
采用停止等待协议。
传播时延ms t p 20=,确认帧长度和处理时间均可忽略。
问帧长为多少才能使信道利用率达到至少50%。
解：根据下图所示停等协议中的时间关系：在确认帧长度和处理时间均可忽略的情况下，要使信道利用率达到至少50%必须使数据帧的发送时间等于2倍的单程传播时延。
即：p f t t 2= 已知：C l t f f =，其中C 为信道容量，或信道速率。
f l 为帧长（以比特为单位）。
所以得帧长16004.040002=⨯=⨯≥⨯=p f f t C t C l bit习题3-09试证明：当用n 个比特进行编号时，若接收窗口的大小为1，则只有在发送窗口的大小WT ≤2n-1时，连续ARQ 协议才能正确运行。
答：（1）显然 WT 内不可能有重复编号的帧，所以WT ≤2n 。
设WT=2n ；（2）注意以下情况：发送窗口：只有当收到对一个帧的确认，才会向前滑动一个帧的位置；接收窗口：只有收到一个序号正确的帧，才会向前滑动一个帧的位置，且同时向发送端发送对该帧的确认。
显然只有接收窗口向前滑动时，发送端口才有可能向前滑动。
发送端若没有收到该确认，发送窗口就不能滑动。
（3）为讨论方便，取n=3。
并考虑当接收窗口位于0时，发送窗口的两个极端状态。
CCNA2 题库
CCNA 2 - Chapter 11What is one advantage of using the cut-through switching method instead of the store-and-forward switching method?has a positive impact on bandwidth by dropping most of the invalid framesmakes a fast forwarding decision based on the source MAC address of the framehas a lower latency appropriate for high-performance computing applications*provides the flexibility to support any mix of Ethernet speeds2A network designer must provide a rationale to a customer for a design which will move an enterprise from a flat network topology to a hierarchical network topology. Which two features of the hierarchical design make it the better choice? (Choose two.)reduced cost for equipment and user trainingless required equipment to provide the same performance levelssimpler deployment for additional switch equipment*easier to provide redundant links to ensure higher availability*lower bandwidth requirements3What are two advantages of modular switches over fixed-configuration switches? (Choose two.)availability of multiple ports for bandwidth aggregationlower forwarding ratesneed for fewer power outlets*lower cost per switchincreased scalability*4Refer to the exhibit. Consider that the main power has just been restored. PC1 asks the DHCP server for IPv4 addressing. The DHCP server sends it an IPv4 address. While PC2 is still booting up, PC3 issues a broadcast IPv4 DHCP request. To which port will SW1 forward this request?to Fa0/1, Fa0/2, and Fa0/4 onlyto Fa0/1, Fa0/2, Fa0/3, and Fa0/4to Fa0/1 and Fa0/2 onlyto Fa0/1, Fa0/2, and Fa0/3 only*to Fa0/1 only5What is one function of a Layer 2 switch?forwards data based on logical addressinglearns the port assigned to a host by examining the destination MAC addressduplicates the electrical signal of each frame to every portdetermines which interface is used to forward a frame based on the destination MAC address*6Refer to the exhibit. Fill in the blank.There are ” 12” collision domains in the topology.7What is a collapsed core in a network design?a combination of the functionality of the access, distribution, and core layersa combination of the functionality of the access and core layersa combination of the functionality of the distribution and core layers*a combination of the functionality of the access and distribution layers 8What are two reasons a network administrator would segment a network with a Layer 2 switch? (Choose two.)to enhance user bandwidth*to eliminate virtual circuitsto create more broadcast domainsto isolate traffic between segments*to isolate ARP request messages from the rest of the networkto create fewer collision domains9Refer to the exhibit.How is a frame sent from PCA forwarded to PCC if the MAC address table on switch SW1 is empty?SW1 forwards the frame directly to SW2. SW2 floods the frame to all ports connected to SW2, excluding the port through which the frame entered the switch.SW1 floods the frame on all ports on the switch, excluding the interconnected port to switch SW2 and the port through which the frame entered the switch.SW1 floods the frame on all ports on SW1, excluding the port through which the frame entered the switch.*SW1 drops the frame because it does not know the destination MAC address.10Place the options in the following order:[+] appropriate for high performance computing applications[+] forwarding process can begin after receiving the destination address [+] may forward invalid frames[#] error checking before forwarding[#] forwarding process only begin after receiving the entire frame [#] only forward valid frames[+] Order does not matter within this group.[#] Order does not matter within this group.11What is a basic function of the Cisco Borderless Architecture distribution layer?aggregating Layer 3 routing boundaries*aggregating all the campus blocksacting as a backboneproviding access to the user12ABC, Inc. has about fifty hosts in one LAN. The administrator would like to increase the throughput of that LAN. Which device will increase the number of collision domains and thereby increase the throughput of the LAN?hubhostNICswitch*13What does the term “port density” represent for an Ethernet switch?the numbers of hosts that are connected to each switch portthe speed of each portthe memory space that is allocated to each switch portthe number of available ports*14Which type of transmission does a switch use when the destination MAC address is not contained in the MAC address table?anycastunicastbroadcast*multicast15What is a basic function of the Cisco Borderless Architecture access layer?aggregates Layer 3 routing boundariesprovides high availabilityaggregates Layer 2 broadcast domainsprovides access to the user*16What information is added to the switch table from incoming frames?source MAC address and incoming port number*destination MAC address and incoming port numberdestination IP address and incoming port numbersource IP address and incoming port number17Fill in the blank.A “converged” network is one that uses the same infrastructure to carry voice, data, and video signals.18An administrator purchases new Cisco switches that have a feature called StackPower. What is the purpose of this feature?It enables many switches to be connected with a special fiber-optic power cable to provide higher bandwidth.It enables the sharing of power among multiple stackable switches.*It enables many switches to be connected to increase port density.It enables many switches to be physically stacked in an equipment rack.It enables AC power for a switch to be provided from a powered patch panel.19Which switch form factor should be used when large port density, fault tolerance, and low price are important factors?fixed-configuration switchmodular switchstackable switch*rackable 1U switch20Refer to the exhibit. Fill in the blank.There are ” 5 ”CCNA 2 - Chapter 2Posted by beotron at 8:59 PM1. A static route that points to the next hop IP will have what administrative distance and metric in the routing table?• administrative distance of 0 and metric of 0• administrative distance of 0 and metric of 1• administrative distance of 1 and metric of 0• administrative distance of 1 and metric of 12. What address can be used to summarize networks 172.16.1.0/24, 172.16.2.0/24, 172.16.3.0/24, and 172.16.4.0/24?• 172.16.0.0/21• 172.16.1.0/22• 172.16.0.0 255.255.255.248• 172.16.0.0 255.255.252.03. The routers in the diagram use the subnet assignments shown. What is the most efficient route summary that can be configured on Router3 to advertise the internal networks to the cloud?• 192.1.1.0/26 and 192.1.1.64/27• 192.1.1.128/25• 192.1.1.0/23 and 192.1.1.64/23• 192.1.1.0/24• 192.1.1.0/25• 192.1.1.0/24 and 192.1.1.64/244. Refer to the exhibit. What is the significance of the /8 in the route to the 10.0.0.0 network?• It indicates that there are 8 hops between this router and the 10.0.0.0 network.• It represents the time, in milliseconds, it takes for a ping to reply when sent to the 10.0.0.0 network.• It indicates that there are 8 subnets in the destination network to which the router can forward packets.• It indicates the number of consecutive bits, from the left, in the destination IP address of a packet that must match 10.0.0.0 to use that route.5. Refer to the exhibit. How will packets destined to the 172.16.0.0 network be forwarded?• Router1 will perform recursive lookup and packet will exit S0/0.• Router1 will perform recursive lookup and packet will exit S0/1.• There is no matching interface associated with network 172.16.0.0 so packets will be dropped.• There is no matching interface associated with network 172.16.0.0 so packets will take gateway of last resort and exit out S0/2.6. A network administrator enters the following command into Router1: ip route 192.168.0.0255.255.255.0 S0/1/0. Router1 then receives a packet that is destined for 192.168.0.22/24. After finding the recently configured static route in the routing table, what does Router1 do next to process the packet? • drops the packet because the destination host is not listed in the routing table• looks up the MAC address of the S0/1/0 interface to determine the destination MAC address of the new frame• performs a recursive lookup for the IP address of the S0/1/0 interface before forwarding the packet• encapsulates the packet into a frame for the WAN link and forwards the packet out the S0/1/0 interface7. Refer to the exhibit. Given the output in the exhibit, how would a clock rate be determined for this link? • The rate would be negotiated by both routers.• A rate would not be selected due to the DCE/DTE connection mismatch.• The rate configured on the DTE determines the clock rate.• The rate configured on the DCE determines the clock rate.8. Refer to the exhibit. Which set of commands will configure static routes that will allow the WinterPark and the Altamonte routers to deliver packets from each LAN and direct all other traffic to the Internet? • WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2Altamonte(config)# ip route 0.0.0.0 0.0.0.0 s0/1• WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2Altamonte(config)# ip route 198.18.222.0 255.255.255.255 s0/1• WinterPark(config)# ip route 172.191.67.0 255.255.255.0 192.168.146.1• WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2• WinterPark(config)# ip route 172.191.67.0 255.255.255.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2Altamonte(config)# ip route 0.0.0.0 0.0.0.0 s0/09. Hosts on two separate subnets cannot communicate. The network administrator suspects a missing route in one of the routing tables. Which three commands can be used to help troubleshoot Layer 3 connectivity issues? (Choose three.)• ping• show arp• traceroute• show ip route• show interface• show cdp neighbor d etail10. Refer to the exhibit. A company network engineer is assigned to establish connectivity between the two Ethernet networks so that hosts on the 10.1.1.0/24 subnet can contact hosts on the 10.1.2.0/24 subnet. The engineer has been told to use only static routing for these company routers. Which set of commands will establish connectivity between the two Ethernet networks?• R1(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.1R2(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.2• R1(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.2R2(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.1• R1(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.2R2(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.1• R1(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.1R2(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.2• R1(config)# ip route 0.0.0.0 0.0.0.0 10.1.2.1R2(config)# ip route 0.0.0.0 0.0.0.0 10.1.1.111. Which of the following are displayed by the Router# show cdp neighbors command? (Choose three.) • load• platform• reliability• holdtime• local interface12. Refer to the exhibit. What two commands are required to provide connectivity between the192.168.1.0 and 10.0.0.0 networks without requiring recursive lookup? (Choose two.)• A(config)# ip route 10.0.0.0 255.0.0.0 s 0/1/0• A(config)# ip route 10.0.0.0 255.0.0.0 172.16.40.2• A (config)# ip route 10.0.0.0 255.0.0.0 s 0/0/0• B(config)# ip route 192.168.1.0 255.255.255.0 s 0/0/0• B (config)# ip route 192.168.1.0 255.255.255.0 172.16.40.1• B(config)# ip route 192.168.1.0 255.255.255.0 s 0/1/013. Refer to the exhibit. What two commands will change the next-hop address for the 10.0.0.0/8 network from 172.16.40.2 to 192.168.1.2? (Choose two.)• A(config)# no network 10.0.0.0 255.0.0.0 172.16.40.2• A(config)# no ip address 10.0.0.1 255.0.0.0 172.16.40.2• A(config)# no ip route 10.0.0.0 255.0.0.0 172.16.40.2• A(config)# ip route 10.0.0.0 255.0.0.0 s0/0/0• A(config)# ip route 10.0.0.0 255.0.0.0 192.168.1.214. What happens to a static route entry in a routing table when the outgoing interface is not available? • The route is removed from the table.• The router polls neighbors for a replacement route.• The route remains in the table because it was defined as static.• The router redirects the static route to compensate for the loss of the next hop device.15. A router has one static route to each destination network. Which two scenarios would require an administrator to alter the static routes that are configured on that router? (Choose two.)• The destination network no longer exists.• The destination network is moved to a different interface on the same router.• The path between the source and destination is upgraded with a higher bandwidth link.• A topology change occurs where the exi sting next-hop address or exit interface is not accessible.• The remote destination network interface has to be down for 15 minutes of maintenance.16. Why is it advisable to enter a next-hop IP address when creating a static route whose exit interface is an Ethernet network?• Adding the next-hop address eliminates the need for the router to do any lookups in the routing table before forwarding a packet.• In a multi-access network, the router cannot determine the next-hop MAC address for the Ethernet frame without a next-hop address.• Using a next-hop address in a static route provides a route with a lower metric.• In multi-access networks, using a next-hop address in a static route makes that route a candidate default route.17. The output of the Router# show interfaces serial 0/1 command displays the following:• Serial0/1 is up, line protocol is down.• What is the most likely cause for the line protocol being down?• Serial0/1 is shutdown.• There is no cable connecting the routers.• The remote rout er is using serial 0/0.• No clock rate has been set.18. Refer to the exhibit. Which static route should be configured on Router1 so that host A will be able to reach host B on the 172.16.0.0 network?• ip route 192.168.0.0 172.16.0.0 255.255.0.0• ip rou te 172.16.0.0 255.255.0.0 192.168.0.1• ip route 172.16.0.0 255.255.0.0 S0/0/1• ip route 172.16.0.0 255.255.0.0 S0/0/019. What two devices are responsible for converting the data from the WAN service provider into a form acceptable by the router? (Choose two).• the serial port of the router• a modem• a switch• the ethernet port of the router• a CSU/DSU device• a DTE device20. Which of the following is true regarding CDP and the graphic shown?• CDP running on Router D will gather information about routers A, B, C, and E.• By default, Router A will receive CDP advertisements from routers B and C.• If routers D and E are running different routing protocols, they will not exchange CDP information.• Router E can use CDP to identify the IOS running on Router B.21. Which two statements describe functions or characteristics of CDP? (Choose two.)• It starts up automatically and allows the device to detect directly connected neighbor devices that use CDP.• It operates at the network layer and allows two systems to learn about each other.• It creates a topology map of the entire network.• It allows systems to learn about each other even if different network layer protocols are configured.• It forwards advertisements about routes for faster convergence.22. Which piece of information is available from examining the output of the command show ip interface brief?• Interface speed and duplex• Interface MTU• Errors• Interface MAC address• Interface IP addressCCNA 2 - Chapter 31A network administrator is determining the best placement of VLAN trunklinks. Which two types of point-to-point connections utilize VLAN trunking? (Choose two.)between two switches that share a common VLANbetween a switch and a server that has an 802.1Q NIC*between a switch and a client PCbetween a switch and a network printerbetween two switches that utilize multiple VLANs*2What happens to a port that is associated with VLAN 10 when the administrator deletes VLAN 10 from the switch?The port automatically associates itself with the native VLAN. The port creates the VLAN again.The port goes back to the default VLAN.The port becomes inactive.*3Refer to the exhibit. Interface Fa0/1 is connected to a PC. Fa0/2 is a trunk link to another switch. All other ports are unused. Which security best practice did the administrator forget to configure?Configure all unused ports to a ‘black-hole’ VLAN that is not used f or anything on the network.Disable autonegotiation and set ports to either static access or static trunk.Change the native VLAN to a fixed VLAN that is distinct from all user VLANs and to a VLAN number that is not VLAN 1.All user ports are associated with VLANs distinct from VLAN 1 and distinct from the ‘black-hole’ VLAN.*4Which command is used to remove only VLAN 20 from a switch?no switchport access vlan 20delete flash:vlan.datno vlan 20*delete vlan.dat5A Cisco Catalyst switch has been added to support the use of multiple VLANs as part of an enterprise network. The network technician finds it necessary to clear all VLAN information from the switch in order to incorporate a new network design. What should the technician do to accomplish this task?Erase the startup configuration and reboot the switch.Erase the running configuration and reboot the switch.Delete the startup configuration and the vlan.dat file in the flash memory of the switch and reboot the switch.*Delete the IP address that is assigned to the management VLAN and reboot the switch.6What is the effect of issuing a switchport access vlan 20 command on the Fa0/18 port of a switch that does not have this VLAN in the VLAN database?VLAN 20 will be created automatically.*The command will have no effect on the switch.Port Fa0/18 will be shut down.An error stating that VLAN 20 does not exist will be displayed and VLAN 20 is not created.Which command displays the encapsulation type, the voice VLAN ID, and the access mode VLAN for the Fa0/1 interface?show mac address-table interface Fa0/1show interfaces Fa0/1 switchport*show interfaces trunkshow vlan brief8Place the options in the following order:- not scored -dynamic autononegotiatedynamic desirabletrunk9Port Fa0/11 on a switch is assigned to VLAN 30. If the command no switchport access vlan 30 is entered on the Fa0/11 interface, what will happen?Port Fa0/11 will be returned to VLAN 1.*VLAN 30 will be deleted.An error message would be displayed.Port Fa0/11 will be shutdown.What must the network administrator do to remove Fast Ethernet port fa0/1 from VLAN 2 and assign it to VLAN 3?Enter the no vlan 2 and the vlan 3 commands in global configuration mode. Enter the switchport trunk native vlan 3 command in interface configuration mode.Enter the switchport access vlan 3 command in interface configuration mode.*Enter the no shutdown in interface configuration mode to return it to the default configuration and then configure the port for VLAN 3.11Which two Layer 2 security best practices would help prevent VLAN hopping attacks? (Choose two.)Disable DTP autonegotiation on end-user ports.*Change the management VLAN to a distinct VLAN that is not accessible by regular users.Statically configure all ports that connect to end-user host devices to be in trunk mode.Change the native VLAN number to one that is distinct from all user VLANs and is not VLAN 1.*Use SSH for all remote management access.12In a basic VLAN hopping attack, which switch feature do attackers take advantage of?automatic encapsulation negotiationthe default automatic trunking configuration*an open Telnet connectionforwarding of broadcasts13A Cisco switch currently allows traffic tagged with VLANs 10 and 20 across trunk port Fa0/5. What is the effect of issuing a switchport trunk allowed vlan 30 command on Fa0/5?It allows only VLAN 30 on Fa0/5.*It allows a native VLAN of 30 to be implemented on Fa0/5.It allows VLANs 1 to 30 on Fa0/5.It allows VLANs 10, 20, and 30 on Fa0/5.14Refer to the exhibit. A frame is traveling between PC-A and PC-B through the switch. Which statement is true concerning VLAN tagging of the frame?No VLAN tag is added to the frame.*A VLAN tag is added when the frame is accepted by the switch.A VLAN tag is added when the frame is forwarded out the port to PC-B.A VLAN tag is added when the frame leaves PC-A.15Refer to the exhibit. PC-A and PC-B are both in VLAN 60. PC-A is unable to communicate with PC-B. What is the problem?The native VLAN is being pruned from the link.The VLAN that is used by PC-A is not in the list of allowed VLANs on the trunk.*The trunk has been configured with the switchport nonegotiate command. The native VLAN should be VLAN 60.16What VLANs are allowed across a trunk when the range of allowed VLANs is set to the default value?All VLANs will be allowed across the trunk.*Only the native VLAN will be allowed across the trunk.The switches will negotiate via VTP which VLANs to allow across the trunk. Only VLAN 1 will be allowed across the trunk.17Under which two occasions should an administrator disable DTP while managing a local area network? (Choose two.)on links that should not be trunking*when connecting a Cisco switch to a non-Cisco switch*on links that should dynamically attempt trunkingwhen a neighbor switch uses a DTP mode of dynamic autowhen a neighbor switch uses a DTP mode of dynamic desirable18Open the PT Activity. Perform the tasks in the activity instructions and then answer the question.Which PCs will receive the broadcast sent by PC-C?PC-D, PC-E*PC-A, PC-B, PC-D, PC-EPC-A, PC-BPC-A, PC-B, PC-D, PC-E, PC-FPC-A, PC-B, PC-E19Which two statements are true about VLAN implementation? (Choose two.)The network load increases significantly because of added trunking information.Devices in one VLAN do not hear the broadcasts from devices in another VLAN.*The size of the collision domain is reduced.VLANs logically group hosts, regardless of physical location.*The number of required switches in a network decreases.20Refer to the exhibit. DLS1 is connected to another switch, DLS2, via a trunk link. A host that is connected to DLS1 is not able to communicate to a host that is connected to DLS2, even though they are both in VLAN 99. Which command should be added to Fa0/1 on DLS1 to correct the problem?switchport trunk allowed vlan add 99switchport trunk native vlan 66*switchport mode dynamic autoswitchport nonegotiate21Which switch feature ensures that no unicast, multicast, or broadcast traffic is passed between ports that are configured with this feature?switch port securityPVLAN protected port*ACLVLAN22Fill in the blank. Use the full command syntax.The ” show vlan brief” command displays the VLAN assignment for all ports as well as the existing VLANs on the switch.23Which three statements accurately describe VLAN types? (Choose three).An 802.1Q trunk port, with a native VLAN assigned, supports both tagged and untagged traffic.*A management VLAN is any VLAN that is configured to access management features of the switch.*A data VLAN is used to carry VLAN management data and user-generated traffic.Voice VLANs are used to support user phone and e-mail traffic on a network. VLAN 1 is always used as the management VLAN.After the initial boot of an unconfigured switch, all ports are members of the default VLAN.*24Which command should the network administrator implement to prevent the transfer of DTP frames between a Cisco switch and a non-Cisco switch?S1(config-if)# switchport mode trunkS1(config-if)# switchport mode accessS1(config-if)# switchport nonegotiate*S1(config-if)# switchport mode dynamic desirableS1(config-if)# switchport trunk allowed vlan noneCCNA 2 - Chapter 41What type of IPv6 address is required as a minimum on IPv6 enabled interfaces?staticglobal unicastlink-local*loopbackunique local2In order for packets to be sent to a remote destination, what three pieces of information must be configured on a host? (Choose three.)default gateway*hostnameDNS server addressDHCP server addressIP address*subnet mask*3What two pieces of information are displayed in the output of the show ip interface brief command? (Choose two.)MAC addressesLayer 1 statuses*IP addresses*next-hop addressesinterface descriptionsspeed and duplex settings4Place the options in the following order:next hopdestination networkmetric- not scored -administrative distanceroute timestamproute source protocol- not scored -5Which two items are used by a host device when performing an ANDing operation to determine if a destination address is on the same local network? (Choose two.)destination MAC addressnetwork numberdestination IP address*source MAC addresssubnet mask*6Refer to the exhibit. A network administrator issues the show ipv6 route command on R1. What two conclusions can be drawn from the routing table? (Choose two.)Packets that are destined for the network 2001:DB8:ACAD:2::/64 will be forwarded through Fa0/1.R1 does not know a route to any remote networks.*The interface Fa0/1 is configured with IPv6 address2001:DB8:ACAD:A::12.*Packets that are destined for the network 2001:DB8:ACAD:2::54/128 will be forwarded through Fa0/0.The network FF00::/8 is installed through a static route command.7Refer to the exhibit. What is the purpose of the highlighted field in the line that is displayed from the show ip route command?It indicates that this is a directly connected route.It indicates that this route has been deleted from the routing table. It indicates that this route was learned via EIGRP.*It indicates that this is a default route.8Which two statements correctly describe the concepts of administrative distance and metric? (Choose two.)The metric varies depending which Layer 3 protocol is being routed, such as IP.A router first installs routes with higher administrative distances. The value of the administrative distance can not be altered by the network administrator.Routes with the smallest metric to a destination indicate the best path.* Administrative distance refers to the trustworthiness of a particular route.*The metric is always determined based on hop count.9What are two functions of a router? (Choose two.)It manages the VLAN database.It increases the size of the broadcast domain.It controls the flow of data via the use of Layer 2 addresses.It determines the best path to send packets.*It connects multiple IP networks.*10A packet moves from a host on one network to a device on a remote network within the same company. If NAT is not performed on the packet, which two items remain unchanged during the transfer of the packet from source to destination? (Choose two.)destination MAC addresssource ARP tablesource IP address*destination IP address*source MAC addressLayer 2 header11。
ccna第二学期练习答案
ERouting Chapter 1 - CCNA Exploration: 路由协议和概念 (版本1口令可用于限制对 Cisco IOS 所有或部分内容的访问。
请选择可以用口令保护的模式和接口。
（选择三项。
）VTY 接口控制台接口特权执行模式2路由器从相连的以太网接口收到消息后，会更改哪项报头地址，再将消息从另一个接口发送出去第 2 层源地址和目的地址3请参见图示。
网络管理员已经为路由器连接到直连网络的接口配置了如图所示的 IP 地址。
从路由器 ping 相连网络上的主机口之间相互 ping 都会遭到失败。
此问题最可能的原因是什么必须使用no shutdown命令启用接口。
4请参见图示。
主机 A ping 主机 B。
当 R4 收到对以太网接口的 ping 时，哪两块报头信息包括在内（选择两项。
）目的 IP 地址：目的 MAC 地址：5网络管理员刚把新配置输入 Router1。
要将配置更改保存到 NVRAM，应该执行哪一条命令Router1# copy running-config startup-config6您需要配置图中所示的串行连接，必须在 Sydney 路由器上发出以下哪条配置命令才能与 Melbourne 站点建立连接（选择三Sydney(config-if)# ip addressSydney no shutdownSydney(config-if)# clock rate 560007请参见图示。
从路由器的运行配置输出可得出什么结论显示的命令决定了路由器的当前运行情况。
8请参见图示。
在主机 2 连接到 LAN 上的交换机后，主机 2 无法与主机 1 通信。
导致此问题的原因是什么主机 1 和主机 2 位于不同的网络中。
9输入以下命令的作用是什么R1(config)# line vty 0 4R1(config-line)# password check123R1(config-line)# login设置通过 Telnet 连接该路由器时使用的口令10以下哪一项正确描述了路由器启动时的顺序加载 bootstrap、加载 IOS、应用配置11加载配置文件时的默认顺序是怎样的NVRAM、TFTP、CONSOLE12请参见图示。
CCNA考试自测题第3卷及答案
CCNA考试自测题第3卷及答案下面的问题将帮助你评价你在本章中学习到的内容。
仔细阅读所有的选项，因为正确答案可能多于1个。
选择每个问题中所有的正确答案。
1) The service provided by IPX is (IPX提供的服务是)：A. Guaranteed deliveryB. DatagramC. Connection-orientedD. Sequenced2) The Transport Control field in the IPX header holds what information? (IPX报头中的传输控制字段保留何种信息)？A. The age of the packet.B. Protocol typeC. Router hop countD. Level of service required.3) What is the length of an IPX network number (IPX网络编号的长度是多少)？A. 16 bitsB. VariableC. 48 bitsD. 32 bits4) In the IPX address 0102.0000.8045.1700, what is the node address ( 在I P X地址0 1 0 2 . 0 0 0 . 8 0 4 5 . 1 7 0 0中，节点地址是多少)？A. 1700B. 0102.0000.8045C. 0102.0000D. 0000.8045.1700A. It is the address of a NetWare print serverB. It is an internal network addressC. The included socket number is 0001D. Nothing6) The Checksum field in the IPX header is normally set to (IPX报头中的校验和字段通常设置为)：A. A checksum of the entire IPX packetB. A checksum of the IPX header fields onlyC. 0xFFFFD. 07) If an IPX node is configured to use the Ethernet_802.2 encapsulation, which other machines can it communicate with directly (without going through a router) on the same network (如果一个I P X节点配置为使用E t h e r n e t _ 8 0 2 . 3封装，它可以和相同网络上其他哪一个设备直接通信(不经过路由器) )？A. Machines running any encapsulationB. Machines running either Ethernet_802.2 or Ethernet_802.3C. Machines running Ethernet_IID. Machines running Ethernet_802.28) To run multiple encapsulations on a single physical interface, a router has to (为在一个物理接口上运行多个封装，路由器必须)：A. Use a different network number for each encapsulationB. Use subinterfaces, not secondary networksC. Enable NLSP routingD. Use an access list9) Which protocol does a workstation use to locate a server providing a particular type of service (工作站使用哪一个协议来找到提供特定类型服务的服务器)？B. NCPC. SAPD. EIGRP10) Periodic SAP updates are sent by (定期S A P更新由谁发出)：A. Routers and serversB. NetWare servers onlyC. Workstations and routersD. Workstations only11) The RIP protocol is used by (RIP协议由谁使用)？A. Routers onlyB. Servers onlyC. Workstations, servers, and routersD. Print servers12) Which command which must be given first to enable IPX (在启用I P X时，必须首先给出哪一个命令)？A. CISCO(CONFIG)#ENABLE IPX ROUTINGB. cisco>ipx routingC. cisco(config-if)#ipx routing onD. cisco(config)#ipx routing13) Which of the following allow you to use multiple IPX networks on a single physical interface (下面哪一个允许你在单个物理接口上使用多个I P X网络)？A. Secondary networksB. Dynamic frame typesC. Subinterfaces14) Which IOS command allows you to view the router’s internal SAP database (哪一个I O S 命令允许你查看路由器的内部S A P数据库)？A. SHOW SERV E R SB. show ipx serversC. serversD. ipx servers15) Which of the following kinds of information do you need to collect before you can configure IPX using IOS (你需要在用I O S配置I P X之前搜集下面各种信息中的哪一个)？A. The number of NetWare servers on the networkB. The encapsulations in useC. IPX network numbersD. The IPX address of another router16) What does this command do:CISCO(CONFIG-IF)#IPX NETWORK 3 (这个命令的作用是什么：C I S C O ( C O N F I G -IF)#IPX NETWORK3)：A. Nothing. It is incomplete.B. Sets up a static route to Network 3C. Configures IPX Network 3 on this interface with the default frame typeD. Nothing. The router is in the wrong configuration mode.17) What does this IOS command do?IPX ROUTE 4 5.0000.8004.4563 FLOAT I N G - S TATIC (这个I O S命令的作用是什么I P X ROUTE 45.0000.8004.4563 FLOAT I N G - S TAT I C )？A. Configures 4 static routesB. Configures static SAP entries for servers of type 4D. Says that to get to network 5, you must go via network 418) In the command IPX ROUTE 4 5.0000.8004.4563 FLOAT I N G - S TATIC, what does the F L O AT I N G - S TATIC keyword on the end mean? ( 在命令IPX ROUTE 45.0000.8004.4563F L O AT I N G.S TAT I C中，最后的F L O AT I N G.S TA T I C意味着什么)？A. Set all static routes to floatingB. Allow this route to be overridden by a route received dynamicallyC. Apply this route to all network numbers from 1 to 4D. Lock this route so that it cannot be changed19) The IPX MAXIMUM-PATHS command does what (IPX MAXIMUM.PAT H S命令的作用是什么)？A. Allows IOS to share traffic to a given network over multiple pathsB. Allows a slow link to be used as a backup for a faster oneC. Sets the maximum number of router hops a packet can travelD. Sets the maximum number of interfaces IPX can be configured on20) Which command is used to show a concise list of the configured IPX interfaces (哪一个命令用于显示配置的I P X接口上的简明列表)？A. SHOW CONFIGB. show ipx interfaceC. show ipx interface briefD. show interface21) If two devices are plugged into the same physical network, but are using diff e r e n t encapsulations, what it required before they can communicate (如果在相同的物理网络中加入了两个设备，但是使用不同的封装，在它们通信之前需要完成什么)？A. A cross-over cableB. A repeaterC. A router configured for the appropriate encapsulations22) When does a workstation normally send a GNS request (工作站一般在什么时候发出G N S请求)？A. When trying to communicate with another workstationB. When trying to locate the nearest routerC. When it needs to send a SAP updateD. When trying to locate a server at initialization23) How many router hops does a GNS request travel (一个G N S请求经过多少个路由器跳)？A. 16B. NoneC. 4D. Unlimited24) In a SAP update packet, what does the Server Address field contain (在S A P更新数据包中，服务器地址字段中包含什么)？A. The network the server is onB. The server’s node numberC. The socket number the server is listening onD. All of the above.25) Which of the following protocols is used by servers to advertise their services to the clients (下面协议中的哪一个由服务器使用，以向客户通告它们的服务)？A. Routing Information protocol (RIP)B. Sequenced Packet Exchange (SPX)C. Network Core Protocol (NCP)D. Service Advertising Protocol (SAP)26) On an Ethernet LAN how many IPX encapsulation types are supported (在一个E t h e r n e t局域网上，可以支持多少个I P X封装)？B. 3C. 2D. 127) The frame check sequence checks with which fields in an Ethernet_802.3 frame (帧校验序列校验E t h e r n e t - 8 0 2 . 3帧中的哪一个字段)？A. The Source Address and Destination AddresB. The packet dataC. Everything from the Destination Address onD. Source Service Access Point (SSAP)28) Which of the following fields is not common to both Ethernet_802.3 and Ethernet_802.2 frames (下面字段中的哪一个不是E t h e r e n e t 8 0 2 . 3和E t h e r n e t 8 0 2 . 3帧所共有的)？A. Source AddressB. LengthC. DSAPD. Data29) In SAP packets, the numbers in the Service Type field are assigned by (在一个S A P数据包中，服务类型字段中的数字由谁给定)？A. The system administratorB. The end userC. NovellD. Server30) SAP requests, responses, or broadcasts can be recognized by which value of source or destination socket number (SAP 请求，响应或广播可以通过源或目的套接字数字中的哪一个值来识别)？A. 0x0452C. 0x03D. 0x045331) In RIP Packets, the Hops Away and Time Ticks fields are valid both for request and response packets (在R I P数据包中，“跳距离”和“时间嘀嗒数”字段对于请求和响应数据包都是合法的)。
CCNA认证基础课程-课后作业.习题答案
CCNA认证基础-习题分析讲义第一部分第一章1. Convert the binary number 10111010 into its hexadecimal equivalent. Select thecorrect answer from the list below. （3）1) 852) 903) BA4) A15) B36) 1C2. Convert the Hexadecimal number A2 into its Base 10 equivalent. Select thecorrect answer from the list below. （4）1) 1562) 1583) 1604) 1625) 1646) 1663. Which binary number is a representation of the decimal number 248? （3）1) 111010002) 111101003) 111110004) 111110104. Which of the following will test the internal loopback of a node? （3）1) ping 10.10.10.12) ping 192.168.1.13) ping 127.0.0.14) ping 223.223.223.2235) ping 255.255.255.2555. What can be verified by successfully pinging the reserved loopback address ona host? （2）1) Connectivity exists between two hosts on the LAN.2) The TCP/IP stack of the local host is configured correctly.3) A connection exists between a host and the default gateway.4) The route a packet takes from the local host to a remote host is valid.6. Which of the following commands could be used on a Windows-basedcomputer to view the current IP configuration of the system? (Choose two.) （3，4）1) configip2) ifconfig3) ipconfig4) winipcfg5) Winipconfig7.Refer to the exhibit. What must be configured on Host B to allow it to communicate withthe Host C? (Choose three.) （2，4，6）1)the MAC address of RTA router interface connected to Switch 12) a unique host IP address3)the IP address of Switch 14)the default gateway address5)the MAC address of Host C6)the subnet mask for the LAN8. What are important characteristics to consider when purchasing a networkinterface card? (Choose two.) （2，3）1) security used on the network2) media used on the network3) system bus used on the computer4) software installed on the network5) diagnostic tools installed on the network第二章1. Select the necessary information that is required to compute the estimated timeit would take to transfer data from one location to another. (Choose two.) （1，5）1) file size2) data format3) network in use4) type of medium5) bandwidth of the link2. Using the data transfer calculation T=S/BW, how long would it take a 4MB file tobe sent over a 1.5Mbps connection? （2）1) 52.2 seconds2) 21.3 seconds3) 6.4 seconds4) 2 seconds5) 0.075 seconds6) 0.0375 seconds3. What are features of the TCP/IP Transport layer? (Choose two.) （3，5）1) path determination2) handles representation, encoding and dialog control3) uses TCP and UDP protocols4) packet switching5) reliability, flow control and error correction4. Which of the following is the Layer 4 PDU? （4）1) bit2) frame3) packet4) Segment5. What is important to remember about the data link layer of the OSI model whenconsidering Peer to Peer communication? (Choose three.) （3，4，5）1) It links data to the transport layer.2) It encapsulates frames into packets.3) It provides a service to the network layer.4) It encapsulates the network layer information into a frame.5) Its header contains a physical address which is required to complete the datalink functions.6) It encodes the data link frame into a pattern of 1s and 0s (bits) for transmissionon the medium.6. Which statement describes a star topology? （2）1) Each host in the network is connected to a backbone cable that is terminated atboth ends.2) Each host is connected to a hub or switch, either of which acts as a central pointfor all network connections.3) Each host is directly connected to two other hosts to form a long chain of hosts.4) Each host has a connection to all other hosts in the network.7. Which statements describe the logical token-passing topology? (Choose two.)（2）1) Network usage is on a first come, first serve basis.2) Computers are allowed to transmit data only when they possess a token.3) Data from a host is received by all other hosts. Electronic tokens are passedsequentially to each other.4) Token passing networks have problems with high collision rates.8. Which technologies are considered to be LAN technologies? (Choose two.) （2，5）1) DSL2) Token Ring3) Frame Relay4) ISDN5) Ethernet9.Refer to the exhibit. Host A wants to send a message to host B. Place the following stepsin the correct order so that the message can be sent. （4）A - add network layer addressesB - transmit bitsC - create application dataD - add data link layer addresses1) B, A, D, C2) D, A, C, B3) A, D, A, B4) C, A, D, B5) C, D, A, B6) C, B, A, D10.After an uns u ccessful ping to the local router, the technician decides to investigate therouter. The technician observes that the lights and fan on the router are not operational.In which layer of the OSI model is the problem most likely occurring? （4）1) transport2) network3) data link4) physical11. Refer t o the exhibit. What is the order of the TCP/IP Protocol Data Units as datais moved as indicated through the OSI model? （3）1) data, segments, frames, packets, bits2) data, packets, segments, frames, bits3) data, segments, packets, frames, bits4) data, packets, frames, segments, bits第三章1. Which combinations of charges will be repelled by electric force? (Choose two.)（4，6）1) neutral and neutral2) neutral and positive3) neutral and negative4) positive and positive5) positive and negative6) negative and negative2. Which of the following are considered the best media for use in data networkcommunications? (Choose three.) （2，3，6）1) glass2) fibers3) copper4) gold5) plastic6) silicon7) Silver3. Which of the following wireless standards increased transmission capabilitiesto 11 Mbps? （2）1) 802.11a2) 802.11b3) 802.11c4) 802.11d4. What is attenuation? （3）1) opposition to the flow of current2) measurement of electrical signals relative to time3) degradation of a signal as it travels along the medium4) amount or volume of traffic that is flowing on the medium5. Which cable specifications are indicated by 10BASE-T? （3）1) 10 Mbps transmission speed, baseband signal, 500 meter cable length, coaxialcable2) 10 Mbps transmission speed, broadband signal, 100 meter cable length, coaxialcable3) 10 Mbps transmission speed, baseband signal, 100 meter cable length,twisted-pair cable4) 10 Gbps transmission speed, broadband signal, 500 meter cable length,twisted-pair cable6. For which Ethernet installations would fiber optic rather than Cat5 UTP be abetter media choice? (Choose two.) （2，4）1) a 3 meter connection between two 10BASE-T hubs2) an environment with many potential sources of EMI and RFI3) a peer to peer connection between two NICs with RJ45 connectors4) an installation between two buildings that are located 500 meters apart5) a single building installation where installation costs are the major concern7. Refer to the exhibit. Which type of UTP cable should be used to connect Host Ato Switch1? （4）1) rollover2) console3) crossover4) straight-through8. Refer to the exhibit. Which type of Category 5 cable is used to make an Ethernetconnection between Host A and Host B? （3）1) coax cable2) rollover cable3) crossover cable4) straight-through cable第四章1. During cable testing, which of the following are used to calculate theinformation carrying capacity of a data cable? (Choose two.) （2，5）1) bit speed2) attenuation3) wire map4) saturation limit5) analog bandwidth2. What type of wiring problem is depicted in this sample of a cable tester? （3）1) a fault2) a short3) an open4) a split a good map3. In a new network installation, the network administrator has decided to use amedium that is not affected by electrical noise. Which cable type will best meet this standard? （5）1) coaxial2) screened twisted pair3) shielded twisted pair4) unshielded twisted pair5) fiber optic4. How does network cable length affect attenuation? （3）1) Category 5 cable that is run in metal conduit has the highest attenuation in theshortest distance.2) Shorter cable lengths have greater signal attenuation.3) Longer cable lengths have greater signal attenuation.4) The length of the cable has no effect on signal attenuation.第五章1. The highest capacity Ethernet technologies should be implemented in whichareas of a network? (Choose three.) （3，4，5）1) between workstation and backbone switch2) between individual workstations3) between backbone switches4) between enterprise server and switch5) on aggregate access links2. What device must be used between an AUI port of a networking device and themedia to which it is being connected? （3）1) a transducer2) a transmitter3) a transceiver4) a transponder5) a port replicator3. An ISDN Basic Rate Interface (BRI) is composed of how many signalingchannels? （1）1) 12) 23) 34) 44. Which layer of the OSI model covers physical media? （1）1) Layer 12) Layer 23) Layer 34) Layer 45) Layer 56) Layer 65. What type of network cable is used between a terminal and a console port? （3）1) cross-over2) straight-through3) rollover4) patch cable6. What is the recommended maximum number of workstations configured on apeer-to-peer network? （3）1) 252) 153) 104) 55) 27. Which of the following increases the potential for a collision to occur? （4）1) the use of an active hub instead of an intelligent hub2) the use of an intelligent hub instead of an active hub3) a reduction in the number of devices attached to the hub4) an increase in the number of devices attached to the hub8. What is the maximum length of a media segment used for 100BASE-TX? （1）1) 100 meters2) 185 meters3) 400 meters4) 500 meters9. Which cable diagram displays the end to end pinout for a crossover cable usedwith Cisco devices? （3）1) Cable A2) Cable B3) Cable C4) Cable D第六章1. What does the "10" in 10Base2 indicate about this version of Ethernet? （2）1) The version uses Base10 numbering within the frames.2) The version operates at a transmission rate of 10 Mbps.3) Frames can travel 10 meters unrepeated.4) The maximum frame length is 10 octets.2. How is a MAC address represented? （4）1) four groups of eight binary digits separated by a decimal point2) four Base10 digits separated by a decimal point3) six hexadecimal digits4) twelve hexadecimal digits5) twenty-four Base10 digits3. Which of the following statements are correct about CSMA/CD? (Choose three.)（1，3，6）1) It is a media access method used in LANs.2) It is a media access method used in FDDI WANs.3) When a device needs to transmit, it checks to see if the media is available.4) A device sends data without checking media availability because all deviceshave equal access.5) Multiple devices can successfully transmit simultaneously.6) Only one device can successfully transmit at a time.4. Which devices shown in the graphic must have a MAC address? （5）1) only PC2) only router3) PC and router4) PC, hub, and router5) PC, printer, and router第七章1. Which of the following items are common to all 100BASE technologies?(Choose three.) （1，4，5）1) frame format2) media3) connectors4) timing5) multi-part encoding2. Which of the following does 1000BASE-T use to accomplish gigabit speeds onCat 5e cable? （4）1) the use of four conductors in full-duplex mode2) the use of two multiplexed pairs of wires, simultaneously3) the use of three pairs of wires for data and the fourth for stabilization andforward error correction4) the use of all four pairs of wires in full-duplex mode, simultaneously3. For which of the following is Ethernet considered the standard? (Choose three.)（1，4，5）1) inter-building connection2) mid-length voice3) video conferencing4) vertical wiring5) horizontal wiring6) diagonal wiring4. To make sure timing limitations are not violated when implementing a 10 MbpsEthernet network involving hubs or repeaters, a technician should adhere to which rule? （4）1) the 4-5-3 rule2) the 6-4-2 rule3) the 3-4-5 rule4) the 5-4-3 rule5. What is the maximum distance that 10BASE-T will transmit data before signalattenuation affects the data delivery? （1）1) 100 meters2) 185 meters3) 300 meters4) 500 meters6. When using Category 5 UTP cable, which RJ-45 pin pairs are used to exchangedata between hosts on an Ethernet network? （2）1) 1 and 2; 4 and 52) 1 and 2; 3 and 63) 3 and 6; 7 and 84) 4 and 5; 7 and 8第八章1. John has been hired as the network administrator of a local company and hasdecided to add more hubs to the company's existing network. Which of the following has been caused by John's inexperience? （1）1) collision domain extended2) an increased number of collision domains3) increased network performance4) increased bandwidth5) extended bandwidth2. "CompA" is trying to locate a new computer named "CompB" on the network.Which of the following does "CompA" broadcast to find the MAC address of "CompB"? （2）1) MAC request2) ARP request3) ping4) Telnet5) proxy ARP3. Which of the following is a term associated with replacing hubs with switchesto increase the number of collision domains? （3）1) encapsulation2) latency3) segmentation4) layered model5) broadcast domain6) Extended4. The accumulation of traffic from which of the following can cause a networkcondition called broadcast radiation? (Choose three.) （3，5，6）1) anonymous FTP servers2) telnet sessions3) video over IP applications4) NAS services5) ARP requests6) RIP updates5. Which of the following describes the use of Spanning Tree Protocol (STP)? （4）1) resolve routing loops2) eliminate Split Horizon errors3) limit collisions4) resolve switching loops6. Which term describes the delay in time that occurs when a frame leaves itssource device and reaches its destination? （4）1) collision2) backoff3) attenuation4) latency5) broadcast7. Based on the graphic above, which of the following occurs as each host systemcomes on line in the topology? （2）1) The switch sends its MAC address to each host.2) The switch adds MAC address to the bridge table as each host sends a frame.3) Each host exchanges MAC addresses with each other.4) The switch listens for data traffic to block since the switch lacks an IP address. 8. Which devices segment collision domains? (Choose two.) （2，3）1) transceiver2) router3) switch4) hub5) media9. Which protocol is used to eliminate switching loops? （3）1) Transmission Control Protocol2) Routing Information Protocol3) Spanning Tree Protocol4) Interior Gateway Routing Protocol5) Internetworking Protocol10. Refer to the exhibit. A network associate needs to establish an Ethernetconnection between Host A and Host B. However, the distance between the two hosts is further than the cabling standards allow. Which two devices that operate at the physical layer of the OSI can be used to allow Host A and Host B to communicate? （2，5）1) switch2) hub3) bridge4) router5) repeater第九章1. Which term describes an ARP response by a router on behalf of a requestinghost? （3）1) ARP2) RARP3) Proxy ARP4) Proxy RARP2. Which protocol functions at the internet layer of the TCP/IP protocol suite? （4）1) File Transfer Protocol (FTP)2) Trivial File Transfer Protocol (TFTP)3) Transmission Control Protocol (TCP)4) Internet Protocol (IP)5) User Datagram Protocol (UDP)6) Simple Mail Transport Protocol (SMTP)3. Which of these workstation installation and setup tasks are concerned withnetwork access layer functions? (Choose two.) （2，4）1) configuring the e-mail client2) installing NIC drivers3) configuring IP network settings4) connecting the network cable5) using FTP to download application software updates4. Which part of an IP address identifies a specific device on a network? （4）1) first two octets2) third and fourth octets3) network portion4) host portion5) only the fourth octet5. Which of the following are features of the Internet Protocol (IP)? (Choose two.)（1，3）1) It is the most widely implemented global addressing scheme.2) It allows two hosts to share a single address on a local area network.3) It is a hierarchical addressing scheme allowing addresses to be grouped.4) It is only locally significant, used primarily on local area networks.6. Which of the following are useable Class A IP addresses with a default subnetmask? (Choose three.) （2，3，5）1) 127.0.39.12) 111.9.28.303) 123.1.2.1324) 128.50.38.25) 105.1.34.16) 0.23.92.37. Which application layer protocols use UDP at the transport layer? (Choose two.)（2，4）1) FTP2) SNMP3) Telnet4) DHCP5) SMTP第十章1. Which OSI layer encapsulates data into packets? （3）1) session2) transport3) network4) data link2. Which OSI layer defines the functions of a router? （3）1) physical2) data link3) network4) transport5) session3. Which of the following are Cisco proprietary routing protocols? (Choose two.)（2，6）1) RIPv22) IGRP3) OSPF4) BGP5) RIPv16) EIGRP4. A company with a Class B license needs to have a minimum of 1,000 subnetswith each subnet capable of accommodating 50 hosts. Which mask below is the appropriate one? （4）1) 255.255.0.02) 255.255.240.03) 255.255.255.04) 255.255.255.1925) 255.255.255.2245. A small company has a class C network license and needs to create five usablesubnets, each subnet capable of accommodating at least 20 hosts. Which of the following is the appropriate subnet mask? （3）1) 255.255.255.02) 255.255.255.1923) 255.255.255.2244) 255.255.255.2406. When a network administrator applies the subnet mask 255.255.255.248 to aClass A address, for any given subnet, how many IP addresses are available to be assigned to devices? （6）1) 10222) 5103) 2544) 1265) 306) 67. Host A is assigned the IP address 10.18.97.55 /21. How many more networkdevices can be assigned to this subnetwork if Host A is the only one that has an IP address assigned so far? （4）1) 2542) 5093) 10214) 20455) 40946) 81908.Refe r to the exhibit. The network administrator wants to create a subnet for thepoint-to-point connection between the two routers. Which subnetwork mask would provide enough addresses for the point-to-point link with the least number of wasted addresses?1) 255.255.255.1922) 255.255.255.2243) 255.255.255.2404) 255.255.255.2485) 255.255.255.2529. What is the correct number of usable subnetworks and hosts for the IP networkaddress 192.168.35.0 subnetted with a /28 mask?1) 6 networks / 64 hosts2) 14 networks / 32 hosts3) 14 networks / 14 hosts4) 30 networks / 64 hosts10. Which subnet masks would be valid for a subnetted Class B address? (Choosetwo.) （5，6）1) 255.0.0.02) 255.254.0.03) 255.224.0.04) 255.255.0.05) 255.255.252.06) 255.255.255.19211. Refer to the exhibit. How will the Fohi router dynamically learn routes to the192.168.16.16/28, 192.168.16.32/28, and 192.168.16.48/28 subnetworks? （3）1) with a static route2) with a routed protocol3) with a routing protocol4) with a directly connected route12. How many broadcast domains are shown in the diagram? （1）1) three2) four3) five4) six5) seven6) eight13. How many collision domains are shown in the diagram? （5）1) three2) four3) five4) six5) seven6) eight14. A router interface has been assigned an IP address of 172.16.192.166 with amask of 255.255.255.248. To which subnet does the IP address belong?1) 172.16.0.02) 172.16.192.03) 172.16.192.1284) 172.16.192.1605) 172.16.192.1686) 172.16.192.17615. Refer to the exhibit. Host A is sending data to Host B. Once R2 determines thatdata from Host A must be forwarded to R1 to reach Host B, which layer of the OSI model will R2 use to address and build the frames destined for R1?1) physical2) data link3) network4) transport5) session6) presentation16. Which type of address is 192.168.170.112/28?1) host address2) subnetwork address3) broadcast address4) multicast address17. Which type of address is 223.168.17.167/29?1) host address2) multicast address3) broadcast address4) subnetwork address18. Which combination of network id and subnet mask correctly identifies all IPaddresses from 172.16.128.0 through 172.16.159.255?1) 172.16.128.0 255.255.255.2242) 172.16.128.0 255.255.0.03) 172.16.128.0 255.255.192.04) 172.16.128.0 255.255.224.05) 172.16.128.0 255.255.255.19219. Refer to the exhibit. The internetwork in the exhibit has been assigned the IPaddress 172.20.0.0. What would be the appropriate subnet mask to maximize the number of networks available for future growth?1) 255.255.224.02) 255.255.240.03) 255.255.248.04) 255.255.252.05) 255.255.254.06) 255.255.255.0第十一章1. If a network administrator needed to download files from a remote server, whichprotocols could the administrator use to remotely access those files? (Choose two.) （3，5）1) NFS2) ASCII3) TFTP4) IMAP5) FTP6) UDP2. What is established during a connection-oriented file transfer betweencomputers? (Choose two.) （2，5）1) a temporary connection to establish authentication of hosts2) a connection used for ASCII or binary mode data transfer3) a connection used to provide the tunnel through which file headers aretransported4) a command connection which allows the transfer of multiple commands directlyto the remote server system5) a control connection between the client and server3. Which of the following protocols are used for e-mail transfer between clientsand servers? (Choose three.) （3，4，5）1) TFTP2) SNMP3) POP34) SMTP5) IMAP46) postoffice4. Which type of institution does the domain suffix .org represent? （4）1) government2) education3) network4) non-profit5. Which of the following services is used to translate a web address into an IPaddress? （1）1) DNS2) WINS3) DHCP4) Telnet6. Which part of the URL http://www.awsb.ca/teacher gives the name of thedomain? （4）1) www2) http://3) /teacher4) awsb.ca7. Which protocols are TCP/IP application layer protocols? (Choose two.) （2，4）1) UDP2) FTP3) IP4) SMTP5) TCP8. What are three characteristics of the TCP protocol? (Choose three.) （3，4，6）1) has less overhead than UDP2) is used for IP error messages3) forces the retransmission undelivered packets4) creates a virtual session between end-user applications5) carries the IP address of destination host in the TCP header6) is responsible for breaking messages into segments and reassembling9. Two peer hosts are exchanging data using TFTP. During the current session, adatagram fails to arrive at the destination. Which statement is true regarding the retransmission of the datagram? （2）1) Datagram retransmission requires user authentication.2) Datagram retransmission is controlled by the application.3) Datagram retransmission relies on the acknowledgements at transport layer.4) Datagram retransmission occurs when the retransmission timer expires in thesource host.案例学习1. 子网计算练习：Answer2. 子网号及广播地址计算练习Answer3. 子网规划练习：已知：给定一个C类地址201.16.5.0/24。
CCNA_ERouting_Chapter_3
1When multiple routing protocols have a route to the same destination network, what determines route is installed in the routing table?best metriclowest hop countgreatest available bandwidthlowest administrative distancelowest cost2A growing medium-sized manufacturing company recently began to have routing instability issue company uses static routes and has a mixture of over 30 Cisco and non-Cisco routers. The netw administrator has decided to convert the network to dynamic routing. What characteristics of pro should be considered in this selection process?Distance vector routing protocols, such as RIP, converge more quickly than do link-state rou protocols.EIGRP can be used on all of the routers in the company.OSPF can be used between the routers.An exterior routing protocol, such as BGP, is recommended for growing companies.3An engineer creates a static route by entering the Router(config)# ip route 10.0.0.0 255.255.25 192.168.1.2 command. What can be concluded about this route?The administrative distance of this route is 1.192.168.1.2 is the address of an interface on this router.This route will display as a directly connected network in the routing table.Packets with a destination IP address of 192.168.1.2 will be forwarded to the 10.0.0.0/24 ne 4W hat is the purpose of a routing protocol?It is used to build and maintain ARP tables.It provides a method for segmenting and reassembling data packets.It allows an administrator to devise an addressing scheme for the network.It allows a router to share information about known networks with other routers.It provides a procedure for encoding and decoding data into bits for packet forwarding.5Which two conditions would create a setting where the use of a distance-vector routing protocol efficient? (Choose two.)the network requires a special hierarchical designfast convergence of the network is crucialthe network is using a hub and spoke topologythe network is using a flat designthere are more than 15 hops between the most distant routers6Which command would the network administrator issue to determine if load balancing is in effect on a router?show ip protocolsshow ip routeshow ip interface briefshow ip interface7W hich of the following best describes the operation of distance vector routing protocols?They use hop count as their only metric.They only send out updates when a new network is added.They send their routing tables to directly connected neighbors.They flood the entire network with routing updates.8Which two statements correctly describe the concepts of administrative distance and metric? (Choose two.)Administrative distance refers to the trustworthiness of a particular route.A router first installs routes with higher administrative distances.The value of the administrative distance can not be altered by the network administrator.Routes with the smallest metric to a destination indicate the best path.The metric is always determined based on hop count.The metric varies depending which Layer 3 protocol is being routed, such as IP or IPX.9T he following line of code is present in the routing table:O 10.16.1.0/27 [110/129] via 192.168.1.5, 00:00:05, Serial0/0/1What does the number 129 indicate in this output?The cost for this link has a value of 129.The clock rate on this serial interface is set to 129,000.The next-hop router is 129 hops away from this router.This route has been updated 129 times in this routing table.10Which of the following conditions must be met in order for a network to have converged?The routers in the network are operating with dynamic routing protocols.The routers in the network are operating with compatible versions of IOS.The routers in the network are operating with the same routing tables.The routers in the network are operating with consistent routing knowledge.11Refer to the exhibit. Router1 and Router2 are running EIGRP. All interfaces are operational and packets can be forwarde networks. What information will be found in the routing table for Router1?Router1 will have 6 directly connected networks.The administrative distance of the route to network 172.16.0.0 will be 90.The metric for routes to 172.16.0.0 will be 1.The interface that is used to forward packets to 172.16.0.0 will always be the S0/1 interface.12W hich two statements are true regarding the advantages of the use of static routes? (Choose two).increased securityreduced effort in configuring routesthe administrator maintains control over routingeasier to implement in a growing networkreduces the chance of routing errorsincreased router resource usage13The following line of code is displayed in a routing table:R 209.165.201.0/24 [120/2] via 192.168.252.2, 00:00:16, S0/0/0What can be concluded from this output?A packet destined for host 192.168.252.2 will be forwarded out the interface connected to network 209.165.201.0/24The value, 120, is used to determine the best path when a router has more than one routing protocol configured for t destination network.This route was manually configured using the ip route command.192.168.252.2 is an interface on the router that produced this output.14W hat will be the result of the following commands?ORL(config)# interface fastethernet 0/0ORL(config-if)# ip address 172.16.3.1 255.255.255.0ORL(config-if)# no shutdownThe 172.16.3.0 network will be routed by any dynamic routing protocol automatically.A routing table entry is made to the 172.16.3.0 network with a code of "C".A static route is required to route traffic to the 172.16.3.0 network.The commands will be saved to the startup-configuration automatically.15Which two statements are true regarding classless routing protocols? (Choose two.)sends subnet mask information in routing updatessends complete routing table update to all neighborsis supported by RIP version 1allows for use of both 192.168.1.0/30 and 192.168.1.16/28 subnets in the same topologyreduces the amount of address space available in an organization16Which two statements are true regarding metrics? (Choose two.)RIP uses bandwidth as a metric.OSPF uses delay as a metric.EIGRP uses bandwidth as a metric.OSPF uses cost based on bandwidth as a metric.RIP uses delay as a metric.EIGRP uses hop count only as a metric.17W hy is fast convergence desirable in networks that use dynamic routing protocols?Routers will not allow packets to be forwarded until the network has converged.Hosts are unable to access their gateway until the network has converged.Routers may make incorrect forwarding decisions until the network has converged.Routers will not allow configuration changes to be made until the network has converged.18Refer to the exhibit. Which statement correctly describes how R1 will determine the best path to R2?R1 will install a RIP route using network A in its routing table because the administrative distance of RIP is higher thaR1 will install a RIP route using network A in its routing table because the path cost from RIP is lower than EIGRP.R1 will install an EIGRP route using network B in its routing table because the administrative distance of EIGRP is loR1 will install an EIGRP route using network B in its routing table because the path cost from EIGRP is lower than RR1 will install an EIGRP route and a RIP route in its routing table and load balance between them.19Refer to the exhibit. If RIP is the routing protocol, what is the value of the metric from router A to network 192.168.5.0/24?345662472420 A router learns two paths with equal metrics to a destination network via the RIP routing protocol. How will the router handlthe destination network?The router will install the first route it learned into the routing table.The router will install both routes in the routing table and load balance between the two.The router will put the first route in the routing table, and denote the second route as a backup route.The router will pick the path with the higher bandwidth and will place it in the routing table.。
CCNA2第3章答案
CCNA2第3章答案1. 第3章简介本章讨论了局域网的部署和故障排除。
局域网是一个小范围内的计算机网络，通常被用于连接办公室或住宅中的设备。
本章重点介绍了局域网的构建和故障排除的一些基本概念和技术。
2. 局域网构建局域网的构建需要考虑以下几个关键因素：2.1 路由器和交换机•路由器是一个网络设备，用于将数据包在不同网络之间转发。
它可以连接不同的局域网，并在它们之间进行通信。
路由器通常具有多个接口，每个接口都可以连接到一个局域网。
•交换机是一个网络设备，用于在局域网内转发数据帧。
它可以将数据帧从一个端口转发到另一个端口，以便设备可以进行通信。
交换机根据MAC地址来转发数据帧，这使得局域网中的设备可以直接通信，而不需要经过路由器。
2.2 VLAN•VLAN（Virtual Local Area Network）是一种将局域网分割为多个虚拟网络的技术。
每个VLAN都有自己的逻辑分组，并且设备只能与同一VLAN中的设备进行通信。
VLAN可以提高网络的性能和安全性。
•VLAN可以通过交换机进行配置。
管理员可以将不同的端口分配给不同的VLAN，从而实现不同设备之间的逻辑隔离。
2.3 IP地址规划•IP地址是互联网上的设备进行通信的唯一标识符。
在构建局域网时，我们需要使用IP地址来唯一标识每个计算机或设备。
•IP地址可以手动配置，也可以通过DHCP服务器进行自动分配。
3. 局域网故障排除在网络运行过程中，可能会出现一些故障。
在这种情况下，我们需要进行故障排除来找出问题所在，并采取相应的措施进行修复。
以下是一些常见的局域网故障排除步骤：3.1 确定问题范围首先，我们需要确定问题的范围。
问题可能只影响特定的设备或特定的网络部分。
通过确定问题的范围，我们可以更方便地定位故障的根源。
3.2 确认基本连接检查设备之间的物理连接是否正确。
确保电缆连接可靠，并且没有松动或损坏。
3.3 使用ping工具测试连接使用ping工具测试设备之间的连通性。
ccna第二学期练习答案中文
ERouting Chapter 1 - CCNA Exploration: 路由协议和概念(版本4.0)1口令可用于限制对Cisco IOS 所有或部分内容的访问。
请选择可以用口令保护的模式和接口。
（选择三项。
）VTY 接口控制台接口特权执行模式2路由器从相连的以太网接口收到消息后，会更改哪项报头地址，再将消息从另一个接口发送出去？第 2 层源地址和目的地址3请参见图示。
网络管理员已经为路由器连接到直连网络的接口配置了如图所示的IP 地址。
从路由器ping 相连网络上的主机口之间相互ping 都会遭到失败。
此问题最可能的原因是什么？必须使用no shutdown命令启用接口。
4请参见图示。
主机 A ping 主机B。
当R4 收到对以太网接口的ping 时，哪两块报头信息包括在内？（选择两项。
）目的IP 地址：192.168.10.134目的MAC 地址：9999.DADC.12345网络管理员刚把新配置输入Router1。
要将配置更改保存到NVRAM，应该执行哪一条命令？Router1# copy running-config startup-config6您需要配置图中所示的串行连接，必须在Sydney 路由器上发出以下哪条配置命令才能与Melbourne 站点建立连接？（选Sydney(config-if)# ip address 201.100.53.2 255.255.255.0Sydney(config-if)# no shutdownSydney(config-if)# clock rate 560007请参见图示。
从路由器的运行配置输出可得出什么结论？显示的命令决定了路由器的当前运行情况。
8请参见图示。
在主机 2 连接到LAN 上的交换机后，主机2 无法与主机 1 通信。
导致此问题的原因是什么？主机 1 和主机2 位于不同的网络中。
9输入以下命令的作用是什么？R1(config)# line vty 0 4R1(config-line)# password check123R1(config-line)# login设置通过Telnet 连接该路由器时使用的口令10以下哪一项正确描述了路由器启动时的顺序？加载bootstrap、加载IOS、应用配置11加载配置文件时的默认顺序是怎样的？NVRAM、TFTP、CONSOLE12请参见图示。
CCNA2. 2014 Chapter 3 (Form A).Answer
CCNA2.Chapter 3 (Form A)1What two tasks do dynamic routing protocols perform? (Choose two.)discover hostsupdate and maintain routing tablespropagate host default gatewaysnetwork discoveryassign IP addressingThis item references content from the following areas: Routing Protocols∙ 3.1.1 Dynamic Routing Protocol Operation2 Which dynamic routing protocol was developed as an exterior gateway protocol to interconnect different Internet providers?BGP EIGRP OSPFRIPBGP is a protocol developed to interconnect different levels of ISPs as well as ISPs and some of their larger private clients.This item references content from the following areas: Routing Protocols∙ 3.1.4 Types of Routing Protocols3 In the context of routing protocols, what is a definition for time to convergence?the amount of time a network administrator needs to configure a routing protocol in a small- to medium-sized networkthe capability to transport data, video, and voice over the same mediaa measure of protocol configuration complexitythe amount of time for the routing tables to achieve a consistent state after a topology changeTime to convergence defines how quickly the routers in the network topology share routing information and reach a state of consistent knowledge.This item references content from the following areas:Routing Protocols∙ 3.1.4 Types of Routing Protocols4 Which two statements are true regarding classless routing protocols? (Choose two.)sends subnet mask information in routing updatessends complete routing table update to all neighborsis supported by RIP version 1allows for use of both 192.168.1.0/30 and 192.168.1.16/28 subnets in the same topologyreduces the amount of address space available in an organizationThis item references content from the following areas:Routing Protocols∙ 3.1.4 Types of Routing Protocols5 What two actions result from entering the network 192.168.1.0 command in RIPconfiguration mode on a router? (Choose two.)The network address 192.168.1.0 is advertised to the neighbor routers.Routing updates are sent through all the interfaces belonging to 192.168.1.0.The routing table is created in the RAM of the router.The RIP process is stopped and all existing RIP configurations are erased.The neighboring routers are sent a request for routing updates.The network statement does not create the routing table. The no router rip global configuration command stops the RIP process and erases all existing RIP configurations. RIP does not request the neighbors to send routing updates.This item references content from the following areas: Routing Protocols∙ 3.3.1 Configuring the RIP Protocol6Refer to the exhibit. Basedon the partial output from the show ip route command, what two facts can be determined about the RIP routing protocol? (Choose two.)RIP version 2 is running on this router and its RIP neighbor.The metric to the network 172.16.0.0 is 120.RIP version 1 is running on this router and its RIP neighbor.The command no auto-summary has been used on the RIP neighbor router.RIP will advertise two networks to its neighbor.The router learned, via RIP, that 172.16.0.0 is variably subnetted, and that there are two subnet and mask entries for that network. This means that RIP version 2 is running on both routers and that the command no auto-summary has been applied on the neighbor router. RIPv2 has an administrative distance of 120 and this router will advertise all connected networks to the neighbor via 192.168.1.1.This item references content from the following areas: Routing Protocols∙ 3.3.1 Configuring the RIP Protocol7 What is the purpose of the passive-interface command?allows a routing protocol to forward updates out an interface that is missing its IP addressallows a router to send routing updates on an interface but not receive updates via that innterfaceallows an interface to remain up without receiving keepalivesallows interfaces to share IP addressesallows a router to receive routing updates on an interface but not send updates via that interfaceThis item references content from the following areas:Routing Protocols3.3.1 Configuring the RIP Protocol8Refer to the exhibit. OSPF is used in the network. Which path will be chosen by OSPF to send data packets from Net A to Net B?R1, R2, R5, R7R1, R3, R5, R7R1, R3, R6, R7R1, R4, R6, R7R1, R3, R5, R6, R7OSPF uses the shortest path first algorithm to select the best path to forward packets. Each path is labeled with a value for cost andthis algorithm accumulates costs along each path, from source to destination. The path chosen from Net A to Net B is R1-R3-R5-R7,that is equal to 5+7+14+2=28, the shortest cost.This item references content from the following areas: Routing Protocols∙ 3.4.1 Link-State Routing Protocol Operation9 Which two events will trigger the sending of a link-state packet by a link-state routing protocol? (Choose two.)the router update timer expiringa link to a neighbor router has become congesteda change in the topologythe initial startup of the routing protocol processthe requirement to periodically flood link-state packets to all neighborsAn LSP (link-state packet) is only sent during initial startup of the routing protocol process on a router; and whenever there is a change in the topology, including a link going down or coming up, or a neighbor adjacency being established or broken. Data traffic congestion does not directly influence routing protocol behavior. LSPs are not flooded periodically, and update timers are not relevant to LSPs.This item references content from the following areas: Routing Protocols∙ 3.4.2 Link-State Updates10 Which two requirements are necessary before a router configured with a link-state routing protocol can build and send its link-state packets? (Choose two.)The router has determined the costs associated with its active links.The router has built its link-state database.The routing table has been refreshed.The router has established its adjacencies.The router has constructed an SPF tree.Once a router has established its adjacencies, it can build its link-state packets (LSPs) that contain the link-state information, including the link cost. A router can only build a link-state after it has received link-state packets from adjacent routers. It then constructs its SPF tree from the least cost routes to remote networks which are used to populate its routing table.This item references content from the following areas: Routing Protocols∙ 3.4.2 Link-State Updates11 A destination route in the routing table is indicated with a code D. Which kind of route entry is this?a static routea route used as the default gatewaya network directly connected to a router interfacea route dynamically learned through the EIGRP routing protocolRoutes in a routing table are manually created or dynamically learned. Letter D indicates that the route was learned dynamically through the EIGRP routing protocol.This item references content from the following areas: Routing Protocols∙ 3.5.1 Parts of an IPv4 Route Entry12Refer to the exhibit. Which interface will be the exit interface to forward a data packet with the destination IP address 172.16.0.66?Serial0/0/0Serial0/0/1GigabitEthernet0/0GigabitEthernet0/1The destination IP address 172.16.0.66 belongs to the network 172.16.0.64/26. In the routing table there is a route learned by EIGRP (identified with code "D") with 192.168.1.6 as the next-hop address and Serial 0/0/1 as the exiting interface.This item references content from the following areas:Routing Protocols3.5.1 Parts of an IPv4 Route Entry13 Which two requirements are used to determine if a route can be considered as an ultimateroute in a router's routing table? (Choose two.)contain subnetsbe a default routecontain an exit interfacebe a classful network entrycontain a next-hop IP addressAn ultimate route is a routing table entry that contains either a next-hop IP address (another path) or an exit interface, or both. This means that directly connected and link-local routes are ultimate routes. A default route is a level 1 ultimate route, but not all ultimate routes are default routes. Routing table entries that are subnetted are level 1 parent routes but do not meet either of the two requirements to be ultimate routes. Ultimate routes do not have to be classful network entries.This item references content from the following areas: Routing Protocols∙ 3.5.2 Dynamically Learned IPv4 Routes14 Which route will a router use to forward an IPv4 packet after examining its routing table for the best match with the destination address?a level 1 child routea level 1 parent routea level 1 ultimate routea level 2 supernet routeIf the best match is a level 1 ultimate route then the router will forward the packet to that network. Level 1 parent route is a route that contains subnets and is not used to forward packets. Level 1 child routes and level 2 supernet routes are not valid routing table entries.This item references content from the following areas: Routing Protocols∙ 3.5.3 The IPv4 Route Lookup Process15 Which route is the best match for a packet entering a router with a destination address of 10.16.0.2?S 10.0.0.0/8 [1/0] via 192.168.0.2S 10.16.0.0/24 [1/0] via 192.168.0.9S 10.16.0.0/16 is directly connected, Ethernet 0/1S 10.0.0.0/16 is directly connected, Ethernet 0/0This item references content from the following areas: Routing Protocols∙ 3.5.3 The IPv4 Route Lookup Process16 What is different between IPv6 routing table entries compared to IPv4 routing table entries?IPv6 routing tables include local route entries which IPv4 routing tables do not.By design IPv6 is classless so all routes are effectively level 1 ultimate routes. The selection of IPv6 routes is based on the shortest matching prefix, unlike IPv4 route selection which is based on the longest matching prefix.IPv6 does not use static routes to populate the routing table as used in IPv4.Routers running IOS release 15 have link local routing table entries for both IPv4 and IPv6. The selection of both IPv6 routes and IPv4 routes is based on the longest matching prefix. The routing tables of both IPv6 and IPv4 use directly connected interfaces, static routes, and dynamically learned routes.This item references content from the following areas: Routing Protocols∙ 3.5.4 Analyze an IPv6 Routing Table17 Which two statements describe the OSPF routing protocol? (Choose two.)automatically summarizes networks at the classful boundarieshas an administrative distance of 100calculates its metric using bandwidthuses Dijkstra's algorithm to build the SPF treeused primarily as an EGPThis item references content from the following areas: Routing Protocols∙ 3.4.2 Link-State Updates18masks with the routing updates.The command version 2 that is issued in router configuration mode enables RIP to function as a classless protocol, advertising the subnet mask with the network number.This item references content from the following areas:Routing Protocols∙ 3.3.1 Configuring the RIP Protocol19route.The default-information originate command, entered in ipv6 configuration mode, propagates the static default route and is commonly used on the router that connects to the ISP.This item references content from the following areas:Routing Protocols∙ 3.3.2 Configuring the RIPng Protocol20Both static and dynamic routing could be used when more than one router is involved. Dynamic routing is when a routing protocol is used. Static routing is when every remote route is entered manually by an administrator into every router in the network topology.This item references content from the following areas:Routing Protocols∙ 3.1.2 Dynamic versus Static Routing21Unlike distance vector routing protocols, a link state routing protocol has a complete map of the internal company network interconnectivity.This item references content from the following areas:Routing Protocols∙ 3.1.4 Types of Routing Protocols22Link-state routing protocols have their advantages and disadvantagea. The advantages are that each router builds a topological map; there is fast convergence; and the LSPs are sent only when there is a change in topology. The disadvantages are the requirements of router and bandwidth resources because of the complexity of the link-state routing protocols.This item references content from the following areas:Routing Protocols∙ 3.4.3 Why Use Link-State Routing Protocols。
计算机网络课后题答案第三章
计算机网络课后题答案第三章(总23页)-CAL-FENGHAI.-(YICAI)-Company One1-CAL-本页仅作为文档封面，使用请直接删除第三章数据链路层301数据链路（即逻辑链路）与链路（即物理链路）有何区别“电路接通了”与“数据链路接通了”的区别何在答：（1）数据链路与链路的区别在于数据链路除链路外，还必须有一些必要的规程来控制数据的传输。
因此，数据链路比链路多了实现通信规程所需要的硬件和软件。
（2）“电路接通了”表示链路两端的结点交换机已经开机，物理连接已经能够传送比特流了。
但是，数据传输并不可靠。
在物理连接基础上，再建立数据链路连接，才是“数据链路接通了”。
此后，由于数据链路连接具有检测、确认和重传等功能，才使不太可靠的物理链路变成可靠的数据链路，进行可靠的数据传输。
当数据链路断开连接时，物理电路连接不一定跟着断开连接。
3-02、数据链路层中的链路控制包括哪些功能试讨论数据链路层做成可靠的链路层有哪些优点和缺点。
答：数据链路层中的链路控制包括以下功能：链路管理；帧同步；流量控制；差错控制；将数据和控制信息分开；透明传输；寻址。
数据链路层做成可靠的链路层的优点和缺点：所谓“可靠传输”就是：数据链路层的发送端发送什么，在接收端就收到什么。
这就是收到的帧并没有出现比特差错，但却出现了帧丢失、帧重复或帧失序。
以上三种情况都属于“出现传输差错”，但都不是这些帧里有“比特差错”。
“无比特差错”与“无传输差错”并不是同样的概念。
在数据链路层使用CRC 检验，能够实现无比特差错的传输，但这不是可靠的传输。
3-03、网络适配器的作用是什么网络适配器工作在哪一层答：络适配器能够对数据的串行和并行传输进行转换,并且能够对缓存数据进行出来,实现以太网协议,同时能够实现帧的传送和接受,对帧进行封闭等.网络适配器工作在物理层和数据链路层。
3-04、数据链路层的三个基本问题（帧定界、透明传输和差错检测）为什么都必须加以解决答：帧定界使收方能从收到的比特流中准确地区分出一个帧的开始和结束在什么地方；透明传输使得不管所传数据是什么样的比特组合，都应当能够在链路上传送，因此很重要；差错控制主要包括差错检测和差错纠正，旨在降低传输的比特差错率，因此也必须解决。
CCNA第二学期考试答案
以下是针对您未获得满分的试题给出的反馈。
某些交互式试题可能不显示您的答案。
分项分数：1与固定配置的交换机相比，模块化交换机具有哪两个优点？（请选择两项。
）正确响应您的响应每台交换机的成本更低可扩展性更高转发率更低需要的电源插座数目更少带宽聚合可以使用多个端口固定配置交换机价格较低，但是它具有指定数量的端口且不能添加端口。
它们提供的高速端口通常比较少。
为了在包含固定配置交换机的网络上扩展交换，需要购买更多的交换机。
这增加了需要使用的电源插座数量。
模块化交换机只需要购买额外的线卡便可以扩展。
带宽聚合也更容易，因为机箱的背板可以为交换机端口线卡提供所需的带宽。
此试题参考以下领域的内容：Routing and Switching Essentials• 1.1.2 交换网络2思科无边界架构接入层的基本功能是什么？正确响应您的响应聚合第 2 层广播域聚合第 3 层路由边界为用户提供访问权提供高可用性思科无边界架构接入层的功能是为用户提供网络访问。
第 2 层广播域聚合、第 3 层路由边界聚合和高可用性是分布层的功能。
也有说答案是聚合第 3 层路由边界此试题参考以下领域的内容：Routing and Switching Essentials• 1.1.1 融合网络3思科无边界架构分布层的基本功能是什么？正确响应您的响应充当主干聚合所有园区块聚合第 3 层路由边界为用户提供访问权思科无边界架构的分布层的一项基本功能是在不同的VLAN 之间路由。
充当主干和聚合园区块是核心层的功能。
为用户提供访问是接入层的功能。
此试题参考以下领域的内容：Routing and Switching Essentials• 1.1.1 融合网络4若将大端口密度、容错和低价作为重要指标，应使用哪个交换机外形因素？正确响应您的响应固定配置交换机模块化交换机可配备机架的1U 交换机可堆叠式交换机堆叠式交换机可以使用特殊电缆实现互联，从而在交换机之间提供高带宽的吞吐量，并像单个大型交换机一样运行。
CCNA第二学期
CCNA 2 - Module 1If a router cannot find a valid configuration file during the startup sequence, what will occur?The router will prompt the user for a response to enter setup mode.Refer to the exhibit. The network administrator has configured the router with the interface IP addresses shown for the directly connected networks. Pings from the router to hosts on the connected networks or pings between router interfaces are not working. What is the most likely problem?The interfaces must be enabled with the no shutdown command.Refer to the exhibit. What can be concluded from the routing table output in the exhibit? (Choose two.) The FastEthernet0/0 and Serial0/0/0 interfaces of this router were configured with an IP address and the no shutdown command.An IP packet received by this router with a destination address of 198.18.9.1 will be forwarded out of the Serial0/0/0 interface.Refer to the exhibit. The frame shown in the exhibit was received by the router. The router interfaces are operational. How will the router process this frame? (Choose two.)The router will change the frame type to one supported by the WAN link before forwarding the frame.The frame was received on the Fa0/0 interface of the router and will be s witched to the S0/0/0 interface.Passwords can be used to restrict access to all or parts of the Cisco IOS. Select the modes and interfaces that can be protected with passwords. (Choose three.)VTY interfaceconsole interfaceprivileged EX EC modeWhich two statements correctly describe the components of a router? (Choose two.)ROM contains diagnostics executed on hardware modules.Flash memory does not lose its contents during a reboot.Refer to the exhibit. After host 2 is connected to the switch on the LAN, host 2 is unable to communicate with host 1. What is the cause of this problem?The subnet mask of host 2 is incorrect.Host 1 and host 2 are on different networks.The switch needs an IP address that is not configured.The router LA N interface and host 1 are on different networks.The IP address of host 1 is on a different network than is the LAN interface of the router.Which are functions of a router? (Choose three.)packet s witchingsegmentation of broadcast domainsselection of best path based on logical addressingRefer to the exhibit. A ll routers have a route in its routing table to each network that is shown in the exhibit. Default routes have not been issued on these routers. What can be concluded about how packets are forwarded in this network? (Choose two.)If RouterA receives a packet that is destined for 192.168.3.146, it will be forwarded out interface S0/0/1.If RouterB receives a packet that is destined for 10.5.27.15, it will be forwarded out interface S0/0/1.The serial connection shown in the graphic needs to be configured. Which configuration commands must be made on the Sydney router to establish connectivity with the Melbourne site? (Choose three.) Sydney(config-if)# ip address 201.100.53.2 255.255.255.0Sydney(config-if)# no shutdownSydney(config-if)# clock rate 56000Refer to the exhibit. What can be concluded from the output of the running-configuration of a router? The commands that are dis played determine the current operation of the router.Refer to the exhibit. Host A pings host B. When R4 accepts the ping into the Ethernet interface, what two pieces of header information are included? (Choose two.)destination IP address: 192.168.10.134destination MAC address: 9999.DADC.1234What is the outcome of entering these commands?R1(config)# line vty 0 4R1(config-line)# password check123R1(config-line)# loginsets the password to be used for connecting to this router via T elnetWhich of the following is the correct flow of routines for a router startup?load bootstrap, load IOS, apply configurationWhat three processes does a router execute when it receives a packet from one network that is destinedfor another network? (Choose three.)decapsulates the Layer 3 packet by stripping off the Layer 2 frame headeruses the destination IP Address in the IP header to look up the next-hop address in the routing tableencapsulates the Layer 3 packet into the new Layer 2 frame and forwards it out the exit interfaceThe network administrator needs to connect two routers directly via their FastEthernet ports. What cable should the network administrator use?cross-overWhich two statements describe characteristics of load balancing? (Choose two.)Load balancing allows a router to forward packets over multiple paths to the same destination network.Unequal cost load balancing is supported by EIGRP.What information about the router and its startup process can be gathered from the output of the show version command? (Choose three.)the last restart methodthe configuration register settingsthe location from where the IOS loadedWhich interfaces in the exhibit could be used for a leased line WAN connection? (Choose two.)14From what location can a router load the Cisco IOS during the boot process? (Choose two.)TFTP serverFlash memoryA network administrator has just entered new configurations into Router1. Which command should be executed to save configuration changes to NVRAM?Router1# copy running-config startup-configWhat is the default sequence for loading the configuration file?NVRAM, TFTP, CONSOLEWhat header address information does a router change in the information it receives from an attached Ethernet interface before information is transmitted out another interface?the Layer 2 source and destination addressCCNA 2 - Module 2Which of the following are displayed by the Router# show cdp neighbors command? (Choose three.)platformholdtimelocal interfaceWhy is it advisable to enter a next-hop IP address when creating a static route whose exit interface is an Ethernet network?In a multi-access network, the router cannot determine the next-hop MAC address for the Ethernet frame without a next-hop address.The output of the Router# show interfaces serial 0/1 command displays the following: Serial0/1 is up, line protocol is down.What is the most likely cause for the line protocol being down?No clock rate has been set.A static route that points to the next hop IP will have what administrative distance and metric in the routing table?administrative distance of 1 and metric of 0Refer to the exhibit. What two commands will change the next-hop address for the 10.0.0.0/8 network from 172.16.40.2 to 192.168.1.2? (Choose two.)A(config)# no ip route 10.0.0.0 255.0.0.0 172.16.40.2A(config)# ip route 10.0.0.0 255.0.0.0 192.168.1.2Refer to the exhibit. A company network engineer is assigned to establish connectivity between the two Ethernet networks so that hosts on the 10.1.1.0/24 subnet can contact hosts on the 10.1.2.0/24 subnet. The engineer has been told to use only static routing for these company routers. Which set of commands will establish connectivity between the two Ethernet networks?R1(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.2R2(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.1Refer to the exhibit. Which static route should be configured on Router1 so that hostA will be able to reach hostB on the 172.16.0.0 network?ip route 172.16.0.0 255.255.0.0 S0/0/0Which address can be used to summarize networks 172.16.0.0/24 thru 172.16.7.0/24?172.16.0.0/21Refer to the exhibit. What is the significance of the /8 in the route to the 10.0.0.0 network?It indicates the number of consecutive bits, from the left, in the destination IP address of a packet that must match 10.0.0.0 to use that route.What two devices are responsible for converting the data from the WAN service provider into a form acceptable by the router? (Choose two).a modema CSU/DSU deviceA network administrator enters the following command into Router1: ip route 192.168.0.0 255.255.255.0 S0/1/0. Router1 then receives a packet that is destined for192.168.0.22/24. After finding the recently configured static route in the routing table, what does Router1 do next to process the packet?encapsulates the packet into a frame for the WAN link and forwards the packet out the S0/1/0 interfaceWhich piece of information is available from examining the output of the command show ip interface brief?Interface IP addressWhich of the following is true regarding CDP and the graphic shown?By default, Router A will receive CDP advertisements from routers B and C.Which two statements describe functions or characteristics of CDP? (Choose two.)It starts up automatically and allows the device to detect directly connected neighbor devices that use CDP.It allows systems to learn about each other even if different network layer protocols are configured.Hosts on two separate subnets cannot communicate. The network administrator suspectsa missing route in one of the routing tables. Which three commands can be used to help troubleshoot Layer 3 connectivity issues? (Choose three.)pingtracerouteshow ip routeWhat happens to a static route entry in a routing table when the outgoing interface is not available?The route is removed from the table.The routers in the diagram use the subnet assignments shown. What is the most efficient route summary that can be configured on Router3 to advertise the internal networks to the cloud?192.1.1.0/25Refer to the exhibit. How will packets destined to the 172.16.0.0 network be forwarded? Router1 will perform recursive lookup and packet will exit S0/0.A router has one static route configured to each destination network. Which two scenarios would require an administrator to alter the static routes that are configured on that router? (Choose two.)The destination network no longer exists.A topology change occurs where the existing next-hop address or exit interface is not accessible.Refer to the exhibit. Given the output in the exhibit, how would a clock rate be determined for this link?The rate configured on the DCE determines the clock rate.Refer to the exhibit. Which set of commands will configure static routes that will allow the WinterPark and the Altamonte routers to deliver packets from each LAN and direct all other traffic to the Internet?WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2Altamonte(config)# ip route 0.0.0.0 0.0.0.0 s0/1Refer to the exhibit. What two commands are required to provide connectivity betw een the 192.168.1.0 and 10.0.0.0 networks without requiring recursive lookup? (Choose two.)A(config)# ip route 10.0.0.0 255.0.0.0 s 0/1/0B(config)# ip route 192.168.1.0 255.255.255.0 s 0/0/0CCNA 2 - Module 3Which two statements correctly describe the concepts of administrative distance and metric? (Choose two.)Administrative distance refers to the trustworthiness of a particular route.Routes with the smallest metric to a destination indicate the best path.Refer to the exhibit. Which statement correctly describes how R1 will determine the best path to R2?R1 will install an EIGRP route using network B in its routing table because the administrative distance of EIGRP is lower than RIP.Which two statements are true regarding classless routing protoc ols? (Choose two.) sends subnet mask information in routing updatesallows for use of both 192.168.1.0/30 and 192.168.1.16/28 subnets in the same topologyWhich command would the network administrator issue to determine if load balancing is in effect on a router?show ip routeWhich statement is true regarding routing protocols?EIGRP uses DUAL to calculate the shortest path and can be configured to do unequal cost load balancing.Which two conditions would create a setting where the use of a distance-vector routing protocol would be efficient? (Choose two.)the network is using a hub and spoke topologythe network is using a flat designWhat is the purpose of a routing protocol?It allows a router to share information about known networks with other rou ters.Which of the following best describes the operation of distance vector routing protocols? They send their routing tables to directly connected neighbors.Which of the following is associated with link-state routing protocols?shortest-path first calculationsWhy is fast convergence desirable in networks that use dynamic routing protocols? Routers may make incorrect forwarding decisions until the network has converged.Which of the following conditions must be met in order for a network to have con verged The routers in the network are operating with consistent routing knowledge.Which two statements are true regarding metrics? (Choose two.)EIGRP uses bandwidth as a metric.OSPF uses cost based on bandwidth as a metric.Which two statements are true regarding the advantages of the use of static routes? (Choose two).increased securitythe administrator maintains control over routingThe following line of code is displayed in a routing table:R 209.165.201.0/24 [120/2] via 192.168.252.2, 00:00:16, S0/0/0What can be concluded from this output?The value, 120, is used to determine the best path when a router has more than one routing protocol configured for the same destination network.What will be the result of the following commands?ORL(config)# interface fastethernet 0/0ORL(config-if)# ip address 172.16.3.1 255.255.255.0ORL(config-if)# no shutdownA routing table entry is made to the 172.16.3.0 network with a code of "C".An engineer creates a static route by entering the Router(config)# ip route 10.0.0.0 255.255.255.0 192.168.1.2 command. What can be concluded about this route?The administrative distance of this route is 1.Refer to the exhibit. Router1 and Router2 are running EIGRP. All interfaces are operational and packets can be forwarded between all networks. What information will be found in the routing table for Router1?The administrative distance of the route to network 172.16.0.0 will be 90.The following line of code is present in the routing table:O 10.16.1.0/27 [110/129] via 192.168.1.5, 00:00:05, Serial0/0/1What does the number 129 indicate in this output?The cost for this link has a value of 129.A growing medium-sized manufacturing company recently began to have routing instability issues. The company uses static routes and has a mixture of over 30 Cisco and non-Cisco routers. The network administrator has decided to convert the network to dynamic routing. What characteristics of protocols should be considered in this selection process?OSPF can be used between the routers.Refer to the exhibit. If RIP is the routing protocol, what is the value of the metric from router A to network 192.168.5.0/24?3A router learns two paths with equal metrics to a destination network via the RIP routing protocol. How will the router handle packets to the destination network?The router will install both routes in the routing table and load balance between the two.CCNA 2 - Module 4Which event will cause a triggered update?a route is installed in the routing tableThree routers running a distance-vector routing protocol lost all power, including the battery backups. When the routers reload, what will happen?They will send updates that include only directly connected routes to their directly connected neighbors.What does the RIP holddown timer do?instructs routers to ignore updates, for a specified time or event, about possible inaccessible routesWhich two statements are true regarding the function of the RIPv1 routing updates? (Choose two).updates are broadcast at regular intervalsbroadcasts are sent to 255.255.255.255Which of the following statements are correct about RIP?will send out an update if there is a failure of a linkWhich two statements describe EIGRP? (Choose two.)EIGRP sends triggered updates whenever there is a change in topology that influences the routing information.EIGRP sends a partial routing table update, which includes just routes that have been changed.Which statement is true regarding cisco’s RIP_JITTER variable?It prevents the synchronization of routing updates by subtracting a random length of time ranging from 0% to 15% of the specified interval time from the next routing update interval.What actions will occur after RouterA loses connectivity to network 114.125.16.0? (Choose two.)RouterB will include network 123.92.76.0 and 136.125.85.0 in its update to RouterA.Router C will learn of the loss of connectivity to network 114.125.16.0 from RouterB.Which of the following methods does split horizon use to reduce incorrect routing information?Information learned from one source is not distributed back to that source.The graphic shows a network that is configured to use RIP routing protocol. Router2 detects that the link to Router1 has gone down. It then advertises the network for this link with a hop count metric of 16. Which routing loop prevention mechanism is in effect?route poisoningWhat is the purpose of the TTL field in the IP header?limits the time or hops that a packet can traverse through the network before it should be discardedWhich of the following can exist in a distance vector network that has not converged? (Choose three.)routing loopsinconsistent traffic forwardinginconsistent routing table entriesRefer to the exhibit. The routers in this network are running RIP. Router A has not received an update from Router B in over three minutes. How will Router A respond?The Invalid timer will mark the route as unusable if an update has not been received in 180 seconds.A network administrator is evaluating RIP versus EIGRP for a new network. The network will be sensitive to congestion and must respond quickly to topology changes. What are two good reasons to choose EIGRP instead of RIP in this case? (Choose two.)EIGRP only updates affected neighbors.EIGRP updates are partial.Refer to the exhibit. What path will packets from the 192.168.1.0/24 network travel to reach the 10.0.0.0/8 network if RIP is the active routing protocol?The path will be router A -> router D -> router E.Which three routing protocols are distance vector routing proto cols? (Choose three).RIPv1EIGRPRIPv2What is a routing loop?a condition where a packet is constantly transmitted within a series of routers without ever reaching its intended destinationWhich two conditions are most likely to cause a routing loop? (Choose two.)inconsistent routing tablesincorrectly configured static routesWhat metric does the RIP routing protocol consider to be infinity?16What does a router running RIP do first with a new route that is received from an advertisement?adjusts the metric for the new route to show the added distance for the routeRefer to the exhibit. If all routers are using RIP, how many rounds of updates will occur before all routers know all networks?3CCNA 2 - Module 5Refer to the exhibit. The network that is shown is running RIPv1. The 192.168.10.0/24 network was recently added and will only contain end users. What command or set of commands should be entered on Router1 to prevent RIPv1 updates from being sent to the end user devices on the new network while still allowing this new network to be advertised to other routers?Router1(config-router)# passive-interface fastethernet 0/0The following line was displayed in the output of the show ip route command.R 192.168.3.0/24 [120/3] via 192.168.2.2, 00:00:30, Serial0/0What is the value of the routing metric?3Which of the following is considered a limitation of RIP v1?RIP v1 does not send subnet mask information in its updates.Refer to the exhibit. The Ethernet interface on Router2 goes down and the administrator notices that the route is still in the Router1 routing table. How much longer will Router1 keep the down network in its routing table before marking it as possibly down?155 secondsRefer to the exhibit. Router1 is running RIPv1. What command was entered into Router1 to configure the gateway of last resort?ip route 0.0.0.0 0.0.0.0 S0/0/1What are three characteristics of the RIPv1 routing protocol? (Choose three.)uses hop count as a metricconsiders a metric of 16 as infinitycalculates metrics using the Bellman Ford algorithmWhich of the following would be the correct command sequence to enable RIP on Router B for all connected networks?RouterB(config)# router ripRouterB(config-router)# network 198.16.4.0RouterB(config-router)# network 210.36.7.0RouterB(config-router)# network 220.17.29.0What is the default update period in seconds for the RIP routing protocol?30Refer to the exhibit. What can be concluded from the routing table output of router B? The default-information originate command has been entered on A.Refer to the exhibit. A network consists of multiple routers. What can be verified when the show ip protocols command is issued on one of the routers in the network? routing protocol configuration in use for IP on this routerRefer to the exhibit. All routers are configured with valid interface addresses in the indicated networks and are running RIPv1. The network is converged. Which routes are present in the routing tables?All routers have all /30 routes. Routers A and E also have some of the /24 routes in their routing table.Which two statements are true regarding the characteristics of RIPv1? (Choose two). It is a distance vector routing protocol.The data portion of a RIP message is encapsulated into a UDP segment.Which command or set of commands will stop the RIP routing process?RouterB(config)# no router ripRefer to the exhibit. All routers in the exhibit are running RIP v1. The network administrator issues the show ip route command on router A. What routes would ap pear in the routing table output if the network is converged? (Choose two).R 192.168.2.0/24 [120/1]R 10.10.1.0/24 [120/2]Which command will display RIP activity as it occurs on a router?debug ip ripRefer to the output from the show ip route command. What can be concluded from the output of this router command?There are two equal cost paths to network 1.0.0.0.Refer to the exhibit. Router1 and Router2 are running the RIPv1 protocol. The network administrator configures the command network 10.1.0.0 on Router1. What network will Router1 advertise to Router2?10.0.0.0/8Refer to the exhibit. Pings between the serial interfaces of the routers are successful. Hosts on each LAN can ping the Fa0/0 interface of the router to which they are directlyconnected through the switch. However, pings between hosts on the 10.1.1.0/24 and 10.1.2.0/24 networks are unsuccessful. What is a likely cause of this problem?RIP is configured incorrectly on R1.What will happen if an interface IP address is entered for the address portion of the network command in a RIPv1 configuration instead of a network address?All interfaces in the same classful network as the configured address will be included in the RIPv1 routing process.Refer to the exhibit. All routers that are shown are running the RIP routing protocol. All unknown IP traffic must be forwarded to the ISP. What router or set of routers are recommended to have both a default route and the default-information originate command issued to implement this forwarding policy?only the gateway routerCCNA 2 - Module 6What two advantages does CIDR provide to a network? (Choose two.)reduced routing table sizereduced routing update trafficRefer to the exhibit. The network administrator wants to create a subnet for the po int-to-point connection between the two routers. Which subnetwork mask would provide enough addresses for the point-to-point link with the least number of wasted addresses?255.255.255.252Refer to the exhibit. A network engineer is summarizing the two groups of routes on router R1 shown in the exhibit. Which summarization will work for all the subnets?192.168.0.0/21Which of the following are contained in the routing updates of classless routing protocols? (Choose two.)32-bit addresssubnet maskWhich of the following problems does VLSM help to alleviate?the shortage of IP addressesWhat does VLSM allow a network administrator to do?utilize multiple subnet masks in the same IP address spaceRefer to the exhibit. What subnet mask will be applied if Router A sends a RIPv1 update for the network 172.16.1.0 to Router B?24Refer to the exhibit. The network administrator wants to minimize the number of entries in Router1’s routing table. What should the administrator implement on the network?CIDRA router has a summary route to network 192.168.32.0/20 installed in its routing table. What range of networks are summarized by this route?192.168.32.0 – 192.168.47.0/24A network administrator is tasked with dividing up a class C network among the QA, Sales, and Administration departments. The QA department is made up of 10 people, the Sales is made up of 28 people, and the Administration has 6. Which two subnets masks adequately address the QA and Sales departments? (Choose two.)255.255.255.224 for Sales255.255.255.240 for QAIn the network shown in the graphic, three bits were borrowed from the host portion of a Class C address. How many valid host addresses will be unused on the three point-to-point links combined if VLSM is not used?84A Class C address has been assigned for use in the network shown in the graphic. Using VLSM, which bit mask should be used to provide for the number of host addresses required on Router A, while wasting the fewest addresses?/27An additional subnet is required for a new Ethernet link between Router1 and Router2 as shown in the diagram. Which of the following subnet addresses can be configured in this network to provide a maximum of 14 useable addresses for this link while wasting the fewest addresses?192.1.1.224/28Which three interior routing protocols support VLSM? (Choose three.)OSPFRIP v2EIGRPRefer to the exhibit. The number of required host addresses for each subnet in a network is listed in the exhibit. This number includes the host address requirements for all router ports and hosts on that subnet. After all device and router port address assignments are determined, what will be the total number of unused host addresses available?29Refer to the exhibit. In the network that is shown, the router interfaces are assigned the first address ineach subnet. Which IP address would be usable for a host on one of the LANs in this network?192.168.2.130/25Refer to the exhibit. Which address is a broadcast address for one of the subnets that are shown in the exhibit?192.168.4.15/29Refer to the exhibit. A network administrator needs to create two subnetworks from 10.0.0.0/8 for a router running RIPv2. The Admin subnet requires 120 hosts and the Sales subnet requires 58 hosts. The network administrator assigned 10.0.1.128/25 to the Admin subnet. The Sales subnet i s given 10.0.1.192/26. What will be the result of this addressing scheme?Because RIPv2 does not support VLSM, the subnet masks will not be allowed.The subnets overlap and will be rejected by the router.Refer to the exhibit. A network technician enters the static route in R1 needed to reach network 10.1.1.0/24. A ping from the S0/0/0 interface on R1 to host B fails. The technician begins testing the network and has the following results:1. pings from R1 to the S0/0/0 interface on R2....successful2. pings from R1 to the Fa0/0 interface on R2....successful3. pings from host B to hosts on the 10.1.1.0/24 network....successful4. pings from host B to the Fa0/0 interface on R2....successful5. pings from R2 to host B....successful.The default gateway on host B is not correctly set.What is a supernet?a summarization of classful addressesCCNA 2 - Module 7Refer to the exhibit. If all routers are running RIP version 2, why is there no route for the 192.168.1.32/27 network?Rip version 2 will auto summarize routes by default.Refer to the exhibit. Which two statements are true? (Choose two.)Router1 will install a route to 192.168.0.0/20Router2 will not install a route to 192.168.16.0/20Refer to the exhibit. Which command on which router will allow Router1 to learn about the 192.168.0.0/20 network?Router2(config-router)# version 2What are two reasons to implement RIP version 2 rather than RIP version 1? (Choose two.)RIP version 2 supports VLS M.。
CCNA第3章考试答案
••试题反馈报告Introduction to Networks (版本6.00) - ITN 第3 章考试以下是针对您未获得满分的试题给出的反馈。
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分项分数：1 两台计算机可以使用什么方法来确保数据包不会因为过多数据发送过快而被丢弃？正确响应您的响应封装访问方法流量控制响应超时为使两台计算机能够有效通信，必须具有让源和目标设置数据传输和接收时间的机制。
为了正确接收数据，流量控制可以确保数据不会发送的太快。
此试题参考以下领域的内容：Introduction to Networks• 3.1.1 规则2 哪种类型的通信会向局域网上的所有设备发送消息？正确响应您的响应广播单播组播全播广播通信是一对所有的通信。
单播通信是一对一的通信。
组播是一对多的通信，其中消息会发送给一组特定主机。
全播不是一个描述消息传输的标准术语。
此试题参考以下领域的内容：Introduction to Networks• 3.1.1 规则3 哪个过程用于将一个消息放入另一消息内以从源传输到目的地？正确响应您的响应流量控制封装访问控制解码封装是将一种消息格式放入另一种消息格式的过程。
例如，一个数据包在封装成帧时如何将其完整放入数据字段中。
此试题参考以下领域的内容：Introduction to Networks• 3.1.1 规则4 Web 客户端向Web 服务器发送一个网页请求。
从客户端的角度来讲，用于准备传输请求的协议栈正确顺序是什么？正确响应您的响应HTTP、TCP、IP、以太网HTTP、IP、TCP、以太网以太网、TCP、IP、HTTP以太网、IP、TCP、HTTP1.HTTP 用于控制Web 服务器和客户端进行交互的方式。
2.TCP 用于管理Web 服务器与客户端之间的每次会话。
3.IP 负责通过最佳路径传输到目标。
4.以太网从IP 获取数据包，并将其格式化以供传输。
此试题参考以下领域的内容：Introduction to Networks• 3.2.1 协议5 下列有关网络协议的陈述哪项是正确的？正确响应您的响应只有在远程网络中的设备之间交换消息时才需要使用网络协议。
CCNA 2 Chapter 3 v5.0 Exam Answers 2013
1A network administrator is determining the best placement of VLAN trunk links. Which two types of point-to-point connections utilize VLAN trunking? (Choose two.)between two switches that share a common VLANbetween a switch and a server that has an 802.1Q NIC*between a switch and a client PCbetween a switch and a network printerbetween two switches that utilize multiple VLANs*2What happens to a port that is associated with VLAN 10 when the administrator deletes VLAN 10 from the switch?The port automatically associates itself with the native VLAN.The port creates the VLAN again.The port goes back to the default VLAN.The port becomes inactive.*3Refer to the exhibit. Interface Fa0/1 is connected to a PC. Fa0/2 is a trunk link to anotherswitch. All other ports are unused. Which security best practice did the administrator forget to configure?Configure all unused ports to a ‘black-hole’ VLAN that is not used for anything on the network.Disable autonegotiation and set ports to either static access or static trunk.Change the native VLAN to a fixed VLAN that is distinct from all user VLANs and to a VLAN number that is not VLAN 1.All user ports are associated with VLANs distinct from VLAN 1 and distinct from the‘black-hole’ VLAN.*4Which command is used to remove only VLAN 20 from a switch?no switchport access vlan 20delete flash:vlan.datno vlan 20*delete vlan.dat5A Cisco Catalyst switch has been added to support the use of multiple VLANs as part of an enterprise network. The network technician finds it necessary to clear all VLAN information from the switch in order to incorporate a new network design. What should the technician do to accomplish this task?Erase the startup configuration and reboot the switch.Erase the running configuration and reboot the switch.Delete the startup configuration and the vlan.dat file in the flash memory of the switch and reboot the switch.*Delete the IP address that is assigned to the management VLAN and reboot the switch.6What is the effect of issuing a switchport access vlan 20 command on the Fa0/18 port of a switch that does not have this VLAN in the VLAN database?VLAN 20 will be created automatically.*The command will have no effect on the switch.Port Fa0/18 will be shut down.An error stating that VLAN 20 does not exist will be displayed and VLAN 20 is not created. 7Which command displays the encapsulation type, the voice VLAN ID, and the access mode VLAN for the Fa0/1 interface?show mac address-table interface Fa0/1show interfaces Fa0/1 switchport*show interfaces trunkshow vlan brief8Place the options in the following order:- not scored -dynamic autononegotiatedynamic desirabletrunk9Port Fa0/11 on a switch is assigned to VLAN 30. If the command no switchport access vlan 30 is entered on the Fa0/11 interface, what will happen?Port Fa0/11 will be returned to VLAN 1.*VLAN 30 will be deleted.An error message would be displayed.Port Fa0/11 will be shutdown.10What must the network administrator do to remove Fast Ethernet port fa0/1 from VLAN 2 and assign it to VLAN 3?Enter the no vlan 2 and the vlan 3 commands in global configuration mode.Enter the switchport trunk native vlan 3 command in interface configuration mode.Enter the switchport access vlan 3 command in interface configuration mode.*Enter the no shutdown in interface configuration mode to return it to the default configuration and then configure the port for VLAN 3.11Which two Layer 2 security best practices would help prevent VLAN hopping attacks? (Choose two.)Disable DTP autonegotiation on end-user ports.*Change the management VLAN to a distinct VLAN that is not accessible by regular users.Statically configure all ports that connect to end-user host devices to be in trunk mode. Change the native VLAN number to one that is distinct from all user VLANs and is not VLAN 1.*Use SSH for all remote management access.12In a basic VLAN hopping attack, which switch feature do attackers take advantage of?automatic encapsulation negotiationthe default automatic trunking configuration*an open Telnet connectionforwarding of broadcasts13A Cisco switch currently allows traffic tagged with VLANs 10 and 20 across trunk port Fa0/5. What is the effect of issuing a switchport trunk allowed vlan 30 command on Fa0/5?It allows only VLAN 30 on Fa0/5.*It allows a native VLAN of 30 to be implemented on Fa0/5.It allows VLANs 1 to 30 on Fa0/5.It allows VLANs 10, 20, and 30 on Fa0/5.14Refer to the exhibit. A frame is traveling between PC-A and PC-B through the switch. Which statement is true concerning VLAN tagging of the frame?No VLAN tag is added to the frame.*A VLAN tag is added when the frame is accepted by the switch.A VLAN tag is added when the frame is forwarded out the port to PC-B.A VLAN tag is added when the frame leaves PC-A.15Refer to the exhibit. PC-A and PC-B are both in VLAN 60. PC-A is unable to communicate with PC-B. What is the problem?The native VLAN is being pruned from the link.The VLAN that is used by PC-A is not in the list of allowed VLANs on the trunk.*The trunk has been configured with the switchport nonegotiate command.The native VLAN should be VLAN 60.16What VLANs are allowed across a trunk when the range of allowed VLANs is set to the default value?All VLANs will be allowed across the trunk.*Only the native VLAN will be allowed across the trunk.The switches will negotiate via VTP which VLANs to allow across the trunk.Only VLAN 1 will be allowed across the trunk.17Under which two occasions should an administrator disable DTP while managing a local area network? (Choose two.)on links that should not be trunking*when connecting a Cisco switch to a non-Cisco switch*on links that should dynamically attempt trunkingwhen a neighbor switch uses a DTP mode of dynamic autowhen a neighbor switch uses a DTP mode of dynamic desirable18Open the PT Activity. Perform the tasks in the activity instructions and then answer the question.Which PCs will receive the broadcast sent by PC-C?PC-D, PC-E*PC-A, PC-B, PC-D, PC-EPC-A, PC-BPC-A, PC-B, PC-D, PC-E, PC-FPC-A, PC-B, PC-E19Which two statements are true about VLAN implementation? (Choose two.)The network load increases significantly because of added trunking information.Devices in one VLAN do not hear the broadcasts from devices in another VLAN.*The size of the collision domain is reduced.VLANs logically group hosts, regardless of physical location.*The number of required switches in a network decreases.20Refer to the exhibit. DLS1 is connected to another switch, DLS2, via a trunk link. A host that is connected to DLS1 is not able to communicate to a host that is connected to DLS2, even though they are both in VLAN 99. Which command should be added to Fa0/1 on DLS1 to correct the problem?switchport trunk allowed vlan add 99switchport trunk native vlan 66*switchport mode dynamic autoswitchport nonegotiate21Which switch feature ensures that no unicast, multicast, or broadcast traffic is passed between ports that are configured with this feature?switch port securityPVLAN protected port*ACLVLAN22Fill in the blank. Use the full command syntax.The ” show vlan brief” command displays the VLAN assignment for all ports as well as the existing VLANs on the switch.23Which three statements accurately describe VLAN types? (Choose three).An 802.1Q trunk port, with a native VLAN assigned, supports both tagged and untagged traffic.*A management VLAN is any VLAN that is configured to access management features of the switch.* A data VLAN is used to carry VLAN management data and user-generated traffic.Voice VLANs are used to support user phone and e-mail traffic on a network.VLAN 1 is always used as the management VLAN.After the initial boot of an unconfigured switch, all ports are members of the default VLAN.* 24Which command should the network administrator implement to prevent the transfer of DTP frames between a Cisco switch and a non-Cisco switch?S1(config-if)# switchport mode trunkS1(config-if)# switchport mode accessS1(config-if)# switchport nonegotiate*S1(config-if)# switchport mode dynamic desirableS1(config-if)# switchport trunk allowed vlan none。
CCNA2思科第二学期v20ERoutingFinalExam3答案
1关于数据包通过路由器传输时的封装和解封的叙述，下列哪三项是正确的？(选择三项。
)路由器修改 TTL 字段，将其值减 1。
路由器将源 IP 更改为送出接口的 IP。
路由器保持相同的源IP和目的IP。
路由器将源物理地址更改为送出接口的物理地址。
路由器将目的IP更改为送出接口的IP。
路由器会从所有接口将数据包转发出去，包括路由器接收数据包时使用的那个接口。
Option1,Option3,andOption4arecorrect.2请参见图示。
当数据包发往哪两个网络时需要路由器执行递归查找？(选择两项。
)10.0.0.0/864.100.0.0/16128.107.0.0/16172.16.40.0/24192.168.1.0/24192.168.2.0/24Option 1 and Option 6 arecorrect.3对于为防止路由环路而通过毒性反转实现的水平分割方法，哪两项叙述正确？(选择两项。
)所有CiscoIOS都会默认启用此方法。
会将一个表示无穷大度量的值分配给路由以将其毒化。
将毒化路由更新发回该更新的发送接口。
指示路由器将可能会影响路由的更改保持一段特定的时间。
限制数据包在被丢弃之前能够在网络中传输的跳数。
Option2andOption3arecorrect.4网络管理员在所示网络图中的路由器B和C上启用了 RIP。
什么命令可防止向路由器 A发送RIP更新? A(config)#routerripA(config-router)#passive-interfaceS0/0B(config)#routerripB(config-router)#network192.168.25.48B(config-router)#network192.168.25.64A(config)#routerripA(config-router)#nonetwork192.168.25.32B(config)#routerripB（config-router）#passive-interfaceS0/0A（config）#norouterrip2pointsforOption45请参见图示。
思科路由CCNA答案第3章练习
第3章练习1?两台讣算机可以使用什么方法来确保数据包不会因为过多数据发送过快而被丢弃？(d)a.访问方法b ?响应超时C.封装d. 流量控制2。
什么是专有协议？(c)a. 可供所有组织或供应商自山使用的协议bo称为TCP / I P协议簇的协议集合c?由控制协议定义和操作的组织开发的协议d ?山私人组织开发且能在所有供应商硕件上运行的协议3?网卡根据哪个地址来决定是否接受帧？( d)a o目的I P地址b. 源以太网地址C.源IP地址do目的MAC地址e。
源MAC地址4. Web客户端向Web服务器发送一个网页请求.从客户端的角度来讲，用于准备传输请求的协议栈正确顺序是什么？(d)a .HTTP、I P、TCP、以太网bo 以太网、TCP、IP、HTTPc. 以太网、IP、TCP. HTTPdo HTTP、TCP、IP、以太网5. 给定网络中的一台计算机与一组特定计算机通信。
这种通信属于哪一类型？(b) a。
广播HTTPbo组播c. ARPd. 单播6. 当主机网卡收到来自网络介质的位时，将使用哪种PDU格式?(c)a.数据段bo文件c o帧do数据包7. 用户正在查看Web服务器上的HTML文档。
哪种协议可将消息分为数据段并管理Web服务器与Web客户端之间每次会话中的数据段？(a)a.T CPbo ARPc. DHCP do HTTP8 .下列有关TCP/IP和OS I模型的说法，哪一项是正确的？(a)a.TCP/IP传输层与OSI第4层提供类似的服务和功能。
思科路由CCNA答案第3章练习bo OSI第7层和TCP/I P应用层提供相同的功能。
Co前三个OSI层描述TCP/IP网络层提供的相同常规服务。
do TCP/IP网络接入层与OSI网络层具有类似的功能。
9. 哪种IEEE标准可使无线网卡连接到山不同制造商制造的无线AP? ( b )a o 8 0 2o 3bo 80 2 o 11c o 802 o 1d。
最新 CCNA第二学期章节测试 第三章 答案
参加考试- ERouting Chapter 3 - CCNA Exploration: 路由协议和概念(版本 4.0)1下列哪两项正确描述了管理距离与度量的概念？（选择两项。
）错误！未找管理距离是指特定路由的可信度。
到引用源。
错误！未找路由器会首先添加具有较大管理距离的路由。
到引用源。
错误！未找网络管理员无法更改管理距离的值。
到引用源。
错误！未找具有到目的地的最小度量的路由即为最佳路径。
到引用源。
错误！未找度量总是根据跳数确定。
到引用源。
错误！未找度量会根据所采用的第 3 层协议（如IP 或IPX）而发生变化。
到引用源。
2请参见图示。
下列关于R1 如何确定与R2 之间最佳路径的陈述中，哪一项正确？错误！未找R1 会将使用网络A 的RIP 路由加入路由表，因为RIP 的管理距离比EIGRP 大。
到引用源。
错误！未找R1 会将使用网络A 的RIP 路由加入路由表，因为RIP 的路径开销比EIGRP 低。
到引用源。
错误！未找R1 会将使用网络B 的EIGRP 路由加入路由表，因为EIGRP 的管理距离比RIP 小。
到引用源。
错误！未找R1 会将使用网络B 的EIGRP 路由加入路由表，因为EIGRP 的路径开销比RIP 低。
到引用源。
错误！未找R1 会将EIGRP 路由和RIP 路由加入路由表，并在它们之间实施负载均衡。
到引用源。
3下列关于无类路由协议的陈述，哪两项是正确的？（选择两项。
）错误！未找在路由更新中发送子网掩码信息到引用源。
错误！未找将完整的路由表更新发送给所有邻居到引用源。
错误！未找受RIP 第1 版支持到引用源。
错误！未找允许在同一拓扑结构中同时使用192.168.1.0/30 和192.168.1.16/28 子网到引用源。
错误！未找减少组织中可用地址空间的大小到引用源。
4网络管理员可使用下列哪一条命令来确定路由器是否启用了负载均衡？错误！未找show ip protocols到引用源。
最新CCNA认证试题及答案「中文版」
最新CCNA认证试题及答案「中文版」1、对于这样一个地址,192.168.19.255/20,下列说法正确的是: ( )(A) 这是一个广播地址(B) 这是一个网络地址(C) 这是一个私有地址(D) 地址在192.168.19.0网段上(E) 地址在192.168.16.0网段上(F) 这是一个公有地址答案：CE注：IP地址中关键是看她的主机位，将子网掩码划为二进制，1对应上面的地址是网络位，0对应的地址是主机位192.168.19.255/20划为二进制为：11000000.10101000.00010011.1111111111111111.11111111.11110000.00000000主机位变成全0表示这个IP的网络地址主机槐涑扇?表示这个IP的广播地址RFC1918文件规定了保留作为局域网使用的私有地址：10.0.0.0 - 10.255.255.255 (10/8 prefix)172.16.0.0 - 172.31.255.255 (172.16/12 prefix)192.168.0.0 - 192.168.255.255 (192.168/16 prefix)2、目前，我国应用最为广泛的LAN标准是基于()的以太网标准.(A) IEEE 802.1(B) IEEE 802.2(C) IEEE 802.3(D) IEEE 802.5答案：C参考知识点：现有标准：IEEE 802.1 局域网协议高层IEEE 802.2 逻辑链路控制IEEE 802.3 以太网IEEE 802.4 令牌总线IEEE 802.5 令牌环IEEE 802.8 FDDIIEEE 802.11 无线局域网记住IEEE802.1-------IEEE802.5的定义以太网是一种计算机局域网组网技术。
IEEE制定的IEEE 802.3标准给出了以太网的技术标准。
它规定了包括物理层的连线、电信号和介质访问层协议的内容。
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1Which two statements correctly describe the concepts of administrative distanc metric? (Choose two.)Administrative distance refers to the trustworthiness of a particular route.A router first installs routes with higher administrative distances.The value of the administarive distance can not be altered by the networkRoutes with the smallest metric to a destination indicate the best path.The metric is always determined based on hop count.The metric varies depending which Layer 3 protocol is being routed, such as2Refer to the exhibit. Which statement correctly describes how R1 will determinepath to R2?R1 will install a RIP route using network A in its routing table because theadministrative distance of RIP is higher than EIGRP.R1 will install a RIP route using network A in its routing table because the pafrom RIP is lower than EIGRP.R1 will install an EIGRP route using network B in its routing table because th administrative distance of EIGRP is lower than RIP.R1 will install an EIGRP route using network B in its routing table because th cost from EIGRP is lower than RIP.R1 will install an EIGRP route and a RIP route in its routing table and load b between them.3 Which two statements are true regarding classless routing protocols? (Choosesends subnet mask information in routing updatessends complete routing table update to all neighborsis supported by RIP version 1allows for use of both 192.168.1.0/30 and 192.168.1.16/28 subnets in the sareduces the amount of address space available in an organization4 Which command would the network administrator issue to determine if load balin effect on a router?s how ip protocolss how ip routes how ip interface briefs how ip interface5 Which two conditions would create a setting where the use of a distance-vectorprotocol would be efficient? (Choose two.)the network requires a special hierarchical designfast convergence of the network is crucialthe network is using a hub and spoke topologythe network is using a flat designthere are more than 15 hops between the most distant routers6 What is the purpose of a routing protocol?It is used to build and maintain ARP tables.It provides a method for segmenting and reassembling data packets.It allows an administrator to devise an addressing scheme for the network.It allows a router to share information about known networks with other route It provides a procedure for encoding and decoding data into bits for packet forwarding.7 Which of the following best describes the operation of distance vector routing pThey use hop count as their only metric.They only send out updates when a new network is added.They send their routing tables to directly connected neighbors.They flood the entire network with routing updates.8 What attribute is associated with link-state routing protocols?split horizonpoison reverselow processor overheadshortest-path first calculations9 Why is fast convergence desirable in networks that use dynamic routing protocRouters will not allow packets to be forwarded until the network has converg Hosts are unable to access their gateway until the network has converged.Routers may make incorrect forwarding decisions until the network has conv Routers will not allow configuration changes to be made until the network ha converged.10 Which of the following conditions must be met in order for a network to have conThe routers in the network are operating with dynamic routing protocols.The routers in the network are operating with compatible versions of IOS.The routers in the network are operating with the same routing tables.The routers in the network are operating with consistent routing knowledge.11 Which two statements are true regarding metrics? (Choose two.)RIP uses bandwidth as a metric.OSPF uses delay as a metric.EIGRP uses bandwidth as a metric.OSPF uses cost based on bandwidth as a metric.RIP uses delay as a metric.EIGRP uses hop count only as a metric.12 Which two statements are true regarding the advantages of the use of static routes? (Choosincreased securityreduced effort in configuring routesthe administrator maintains control over routingeasier to implement in a growing networkreduces the chance of routing errorsincreased router resource usage13 The following line of code is displayed in a routing table:R 209.165.201.0/24 [120/2] via 192.168.252.2, 00:00:16, S0/0/0What can be concluded from this output?A packet destined for host 192.168.252.2 will be forwarded out the interface connected t209.165.201.0/24.The value, 120, is used to determine the best path when a router has more than one rou protocol configured for the same destination network.This route was manually configured using the ip route command.192.168.252.2 is an interface on the router that produced this output.14 What will be the result of the following commands?ORL(config)# interface fastethernet 0/0ORL(config-if)# ip address 172.16.3.1 255.255.255.0ORL(config-if)# no shutdownThe 172.16.3.0 network will be routed by any dynamic routing protocol automatically.A routing table entry is made to the 172.16.3.0 network with a code of "C".A static route is required to route traffic to the 172.16.3.0 network.The commands will be saved to the startup-configuration automatically.15 An engineer creates a static route by entering the Router(config)# ip route 10.0.0.0 255.255192.168.1.2 command. What can be concluded about this route?The administrative distance of this route is 1.192.168.1.2 is the address of an interface on this router.This route will display as a directly connected network in the routing table.Packets with a destination IP address of 192.168.1.2 will be forwarded to the 10.0.0.0/24 first.16Refer to the exhibit. Router1 and Router2 are running EIGRP. All interfaces are operational a packets can be forwarded between all networks. What information will be found in the routing Router1?Router1 will have 6 directly connected networks.The administrative distance of the route to network 172.16.0.0 will be 90.The metric for routes to 172.16.0.0 will be 1.The interface that is used to forward packets to 172.16.0.0 will always be the S0/1 interfa 17 The following line of code is present in the routing table:O 10.16.1.0/27 [110/129] via 192.168.1.5, 00:00:05, Serial0/0/1What does the number 129 indicate in this output?The cost for this link has a value of 129.The clock rate on this serial interface is set to 129,000.The next-hop router is 129 hops away from this router.This route has been updated 129 times in this routing table.18 A growing medium-sized manufacturing company recently began to have routing instability iscompany uses static routes and has a mixture of over 30 Cisco and non-Cisco routers. The n administrator has decided to convert the network to dynamic routing. What characteristics of should be considered in this selection process?Distance vector routing protocols, such as RIP, converge more quickly than do link-state protocols.EIGRP can be used on all of the routers in the company.OSPF can be used between the routers.An exterior routing protocol, such as BGP, is recommended for growing companies.19Refer to the exhibit. If RIP is the routing protocol, what is the value metric from router A to network 192.168.5.0/24?345662472420 A router learns two paths with equal metrics to a destination network via the RIP routing protwill the router handle packets to the destination network?The router will install the first route it learned into the routing table.The router will install both routes in the routing table and load balance between the two.The router will put the first route in the routing table, and denote the second route as a ba route.The router will pick the path with the higher bandwidth and will place it in the routing tabl。