ERouting Chapter 10 - CCNA Exploration
信号与系统奥本海姆英文版课后答案chapter10
∞
−n
n =−∞
∑ (1/ 4)
∞
z −n zn
n =−3
∑ (1/ 4)
= ∑ (1/ 4) − n +3 z n −3
n=0
= (1/ 64) z −3 /(1 − 4 z ), z < 1/ 4 = (1/16) z −4 /(1 − (1/ 4) z −1 ), z < 1/ 4
The Fourier transform does not exist because the ROC includes the unit circle. (g) Consider x1 ( z ) = 2n μ[ − n].
X ( z) =
n =−∞
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r> 1 . The second summation
2
10.2
∑ ( 5 ) u[n − 3]z
n
∞
1
z −3 ∞ 1 n − n ]∑ ( ) z =[ 125 n = 0 5
∞ 1 = ∑ ( )n z − n n =3 5 z −3 1 ] =[ 125 1 − 1 z −1 5 −n
X ( Z ) = ∑ x[n]z − n
n =∞ ∞
−5
= ∑ (−1) n z − n
n =0
∞
= 1/(1 + z −1 ), z > 1
The Fourier transform does not exist because the ROC does not include the unit circle (d) For x [n]= ( 1 ) n +1 μ[n + 3],
x( z ) =
CCNA2 思科第二学期 v2.0 ERouting Chapter 7答案
请参见图示。
如果所有路由器都运行RIP 第2 版，为什么没有192.168.1.32/27 网络的路由？Rip 第2 版不会在更新中发送子网掩码。
路由器A 并未将RIP 设置为路由协议。
Rip 第2 版默认将自动总结路由。
路由器B 未设置为通告192.168.1.64/30 网络。
2 points for Option 3请参见图示。
下列哪个路由器上的哪条命令可让Router1 获知192.168.0.0/20 网络？Router1(config)# ip classlessRouter1(config-router)# no passive-interface serial 0/1/1Router2(config-router)# version 2Router2(config-router)# neighbor 10.0.0.22 points for Option 3哪两项是选择实施RIP 第 2 版而不是RIP 第 1 版的原因？（选择两项。
）RIP 第2 版支持VLSM。
RIP 第2 版支持16 台以上的路由器。
RIP 第2 版支持有类（而不是无类）路由RIP 第2 版支持路由更新验证。
RIP 第2 版支持多区域。
RIP 第2 版使用Dijkstra 算法而不是贝尔曼-福特算法。
Option 1 and Option 4 are correct.RIP v1 和RIP v2 的相似点有哪些？（选择三项。
）两者都使用跳数作为度量。
两者对无穷距离使用相同的度量值。
两者都向邻居广播其更新。
两者都在更新中发送子网掩码信息。
两者都对更新来源进行身份验证。
两者都使用水平分割来防止路由环路。
Option 1, Option 2, and Option 6 are correct.请参见图示。
路由器East 和West 被配置为使用RIPv1。
两台路由器都会发送有关其直连路由的更新。
East 路由器可以ping 通West 路由器的串行接口，West 可以ping 通East 的串行接口。
routing congestion意思
routing congestion意思
"Routing congestion" 是一个与网络通信相关的术语，它指的是在网络中路由路径上发生的拥塞情况。
当网络中的数据流量增加到超过网络设备或链路的处理能力时，就会发生路由拥塞。
这可能导致数据包延迟、丢失或传输速度减慢。
路由拥塞可能发生在网络的各个层面，如局域网（LAN）、广域网（WAN）或互联网。
它可能由多种因素引起，包括网络带宽不足、路由器性能限制、链路故障或不合理的路由配置。
为了解决路由拥塞问题，可以采取一些措施，如增加网络带宽、升级路由器硬件、优化路由协议、实施流量工程或使用负载均衡技术。
此外，网络管理员还可以监控网络流量并对拥塞情况进行实时调整，以确保网络的高效运行。
总的来说，"routing congestion" 是指网络中由于数据流量过大而导致的路由路径拥塞情况，解决它对于提高网络性能和可靠性至关重要。
上外综合教程第二版unit10电子教案
上外综合教程第⼆版unit10电⼦教案Unit 10 The TransactionSection One Pre-reading Activities (1)I. Audiovisual Supplement (1)II．Cultural Background (2)Section Two Global Reading (3)I. Text Analysis (3)II. Structural Analysis (3)Section Three Detailed Reading (4)I. Text 1 (4)II. Questions (5)III.Words and Expressions (6)IV. Sentences (8)Section Four Consolidation Activities (8)Ⅰ.Vocabulary (8)Ⅲ. Translation (13)Ⅳ. Exercises for Integrated Skills (14)Ⅴ. Oral Activities (15)Ⅵ. Writing (16)Section Five Further Enhancement (18)I. Lead-in Questions (18)II. Text 2 (18)III. Memorable Quotes (21)Section One Pre-reading ActivitiesI. Audiovisual SupplementWatch the video clip and answer the following questions.Script:Mr. Keating: G o on. Rip it out. Thank you Mr. Dalton. Gentlemen, tell you what, don’t just tear out that page, tear out the entire introduction. I want it gone, history. Leave nothingof it. Rip it out. Rip! Begone J. Evans Pritchard, Ph.D. Rip. Shred. Tear. Rip it out! Iwant to hear nothing but ripping of Mr. Pritchard. We’ll perforate it, put it on a roll.It’s not the Bible. You’re not going to go to hell for this. Go on. Make a clean tear. Iwant nothing left of it.Cameron:We shouldn’t be doing this.Neil: Rip! Rip! Rip!Mr. Keating: Rip it out! Rip!McAllister: What the hell is going on here?Mr. Keating: I don’t hear enough rips.McAllister: Mr. Keating.Mr. Keating: Mr. McAllister.McAllister: I’m sorry, I—I didn’t know you were here.Mr. Keating: I am.McAllister: Ah, so you are. Excuse me.Mr. Keating: Keep ripping gentlemen. This is a battle, a war. And the casualties could be your hearts and souls. Thank you Mr. Dalton. Armies of academics going forward,measuring poetry. No, we will not have that here. No more of Mr. J. Evans Pritchard.Now in my class you will learn to think for yourselves again. You will learn to savorwords and language. No matter what anybody tells you, words and ideas can changethe world.（在每个问题下⾯设置按钮，点击以后出现下⾯的答案）1. What does Mr. Keating ask students to do?He asks students to rip the introduction part of the poetry text book.2. What is the purpose of his doing so?His intention is to develop the students’ ability of independent thinking which is quite important in literature study. He believes that words and ideas can change the world.II．Cultural BackgroundThe Importance of DialogueMany philosophers and writers would like to express their philosophic ideas through the form of dialogue. And one important theorist making great contribution in clarifying the function of dialogic thinking is Mikhail Bakhtin.1) Self-other relationship —―other‖ plays a key role in understanding:In order to understand, it is immensely important for the person who understands to be located outside the object of his or her creative understanding — in time, in space, in culture.—Mikhail Bakhtin (from New York Review of Books, June 10, 1993)2) Polyphony (many voices) — single voice is not the carrier of truth:Truth is a number of mutually addressed, albeit contradictory and logically inconsistent, statements. Truth needs a multitude of carrying voices.Section Two Global ReadingI. Text AnalysisThe text opens with two writers answering student s’ questions about how to write in dialogue, showing sharp contrasts from various aspects. By summarizing different methods in writing, the text later on points out that even with diversity and differentiation, the common ground of any writing is the same. Many renowned philosophers and writers such as Plato and Oscar Wilde expressed their philosophic ideas in the form of dialogue where different aspects of truth were better presented. Through dialogue between people on an equal footing, we get the revelation that different, sometimes even seemingly contradictory elements, can co-exist so harmoniously within the range of one truth. Human beings have an inclination to look at the world from a self-centered perspective, and it will result in an illusion far from truth. Therefore, it is important for one to try his best to train his mind from an early time in his life to tolerate other peo ple’s opinions of the world because such different understanding of life helps one better pursue the truth.II. Structural Analysis1) In terms of organization, the article clearly falls into two main parts:The first part (Paragraphs 1-17) is devoted to answers given by two writers to the students’questions.The second part (Paragraphs 18-22) is a generalization of the essence of writing.2) In order to deliver the sharp differences in the answers of the two writers in the first part, the author uses●Short paragraphs and the repetition of ―he said …‖ and ―Then I said …‖●The rhetorical trick of contraste.g. ―The words just flowed. It was easy.‖ (Paragraph 3) vs. ―It was hard and lonely, and thewords seldom just flowed.‖ (Paragraph 4)●Advantage of such rhetoric technique: some knowledge of different and even conflictingideas helps one to gain greater thinking power and acquire a broader vision.3) The diversity of the writing methods in the second part is expressed by the parallel use of―some …‖ and ―others …‖e.g. Some people write by day, others by night. Some people need silence, others turn on the radio. (Paragraph 18)4) The transition paragraph from the specific examples to general discussion of the topic is Paragraph 17; The shift from the diversity to the commonality shared by all writers is realized with two words ―But all‖ in the beginning of Paragraph 19. Section Three Detailed ReadingI. Text 1The TransactionWilliam Zinsser1 About ten years ago a school in Con necticut held ―a day devoted to the arts,‖ and I was asked if I would come and talk about writing as a vocation. When I arrived I found that a second speaker had been invited —Dr. Brock (as I’ll call him), a surgeon who had recently begun to write and had sold some stories to national magazines. He was going to talk about writing as an avocation. That made us a panel, and we sat down to face a crowd of student newspaper editors, English teachers and parents, all eager to learn the secrets of our glamorous work.2 Dr. Brock was dressed in a bright red jacket, looking vaguely bohemian, as authors are supposed to look, and the first question went to him. What was it like to be a writer?3 He said it was tremendous fun. Coming home from an arduous day at the hospital, he would go straight to his yellow pad and write his tensions away. The words just flowed. It was easy.4 I then said that writing wasn’t easy and it wasn’t fun. It was hard and lonely, and the words seldom just flowed.5 Next Dr. Brock was asked if it was important to rewrite. ―Absolutely not,‖ he said. ―Let it all hang out, and whatever form the sentences take will reflect the writer at his most natural.‖6 I then said that rewriting is the essence of writing. I pointed out that professional writers rewrite their sentences repeatedly and then rewrite what they have rewritten. I mentioned that E. B. White and James Thurber rewrote their pieces eight or nine times.7 ―What do you do on days when it isn’t going well?‖ Dr. Brock was a sked. He said he just stopped writing and put the work aside for a day when it would go better.8 I then said that the professional writer must establish a daily schedule and stick to it. I said that writing is a craft, not an art, and that the man who runs away from his craft because he lacks inspiration is fooling himself. He is also going broke.9 ―What if you’re feeling depressed or unhappy?‖ a student asked. ―Won’t that affect your writing?‖10 Probably it will, Dr. Brock replied. Go fishing. Take a walk.11 Probably it won’t, I said. If your job is to write every day, you learn to do it like any other job.12 A student asked if we found it useful to circulate in the literary world. Dr. Brock said that he was greatly enjoying his new life as a man of letters, and he told several stories of being taken to lunch by his publisher and his agent at chic Manhattan restaurants where writers and editors gather.I said that professional writers are solitary drudges who seldom see other writers.13 ―Do you put symbolism in your writing?‖ a student asked me.14 ―Not if I can help it,‖ I replied. I have an unbroken record of missing the deeper meaning in any story, play or movie, and as for dance and mime, I have never had even a remote notion of what is being conveyed.15 ―I love symbols!‖ Dr. Brock exclaimed, and he described with gusto the joys of weaving them through his work.16 So the morning went, and it was a revelation to all of us. At the end Dr. Brock told me he was enormously interested in my answers —it had never occurred to him that writing could be hard. I told him I was just as interested in his answers —it had never occurred to me that writing could be easy. (Maybe I should take up surgery on the side.)17 As for the students, anyone might think we left them bewildered. But in fact we probably gave them a broader glimpse of the writing process than if only one of us had talked. For of course there isn’t any ―right‖ way to do such intensely personal work. There are all kinds of writers and all kinds of methods, and any method that helps people to say what they want to say is the right method for them.18 Some people write by day, others by night. Some people need silence, others turn on the radio. Some write by hand, some by typewriter or word processor, some by talking into a tape recorder. Some people write their first draft in one long burst and then revise; others can’t write the second paragraph until they have fiddled endlessly with the first.19 But all of them are vulnerable and all of them are tense. They are driven by a compulsion to put some part of themselves on paper, and yet they don’t just write what comes naturally. They sit down to commit an act of literature, and the self who emerges on paper is a far stiffer person than the one who sat down. The problem is to find the real man or woman behind all the tension.20 For ultimately the product that any writer has to sell is not the subject being written about, but who he or she is. I often find myself reading with interest about a topic I never thought would interest me —some unusual scientific quest, for instance. What holds me is the enthusiasm of the writer for his field. How was he drawn into it? What emotional baggage did he bringalong? How did it change hi s life? It’s not necessary to want to spend a year alone at Walden Pond to become deeply involved with a writer who did.21 This is the personal transaction that’s at the heart of good nonfiction writing. Out of it come two of the most important qualities that this book will go in search of: humanity and warmth. Good writing has an aliveness that keeps the reader reading from one paragraph to the next, and it’s not a question of gimmicks to ―personalize‖ the author. It’s a question of using the English language in a way that will achieve the greatest strength and the least clutter.22 Can such principles be taught? Maybe not. But most of them can be learned.II. Questions1.Do you think the process of the activity is within the expectation of both the speakers and theaudience? (Paragraphs 1-17)No. Due to the differences in the background of the two speakers, different views towards the topic of writing are somewhat anticipated. But the fact that their opinions should be so conflicting to each other is a surprise to both the speakers and the audience.2.What would be the possible response of the students as suggested by the writer?(Paragraph17)The students might have a broader glimpse of the writing process. They would realize that there might be totally different writers and methods of writing and the most effective method of writing is the one that helps the writer to say what he wants to say.3.What does the writer mean when he says that all of the writers are ―vulnerable and tense‖?(Paragraph 19)―Vulnerable‖ refers to the quality of being sensitive to all the stimulus in life, and ―tense‖ refers to the sharp awareness of expressing natural feelings in an artistic way.4.What does the writer think is the very thing that makes a piece of good writing? (Paragraph21)According to the writer, it’s the existence of the personal transaction that makes a piece of good writing. The writer should devote genuine emotion in the process of writing and only thus can he arouse the expected response in his readers.5.What does the writer mean that such principles cannot be taught but can be learned?(Paragraph 22)What can be taught in writing is the writing skills, but writing skills alone cannot make a great, or even a good, piece of writing. The genuine enthusiasm for art and sincere emotion for the world, which are essential to good writing, can only be learned by heart and through one’s life experiences.Class Activity （放在课⽂的末尾）Group discussion: Do you enjoy the process of writing? Do you write with the flow of thought or based on careful planning and meditation? Share your experiences with you classmates. Impromptu writing: Use ten minutes to write whatever in your mind on a piece of paper and read this writing to the class.III.Words and ExpressionsParagraphs1-17bohemian a.having or denoting the qualities of a person with artistic or literary interests who disregards conventional standards of behaviore.g. bohemian cafes frequented by artists, musicians, and actorsarduous a.involving strenuous effort, difficult and tiringe.g.After a long, hot, and arduous journey we fell asleep the moment our heads touched the pillows.The experiment was far more arduous than most of us had expected.Antonym:facilecirculate v.move around a social function to talk to different people; move continuously through a closed system or areae.g. Rumours started to circulate among the villagers about the cause of his death right after hedied.Derivation:circulation (n.)e.g. This kind of stamp is no longer in circulation.symbolism n.Symbolism is an artistic and poetic movement or style using symbolic images and indirect suggestion to express mystical ideas, emotions, and states of mind. It originated in late 19th-century France and Belgium, flourished all over Europe, had great international impact, and influenced 20th-century art and literature.e.g. poetry full of religious symbolismDerivations:symbol (n.), symbolic (a.), symbolize (v.)Practice:What does this ____ ____? (symbol, symbolize) symbolize这个符号象征着什么？bewilder v.cause sb. to become perplexed and confusede.g. He was bewildered by his daughter's reaction.Synonyms:puzzle, perplex, confoundParagraphs18-22fiddle v.tinker with sth. in an attempt to make minor adjustments or improvementse.g. She sat in the car and played the radio, fiddling with the knobs.Collocations:fiddle withe.g. Feeling nervous when facing the interviewer, she fiddled with the strings of her purse.fiddle about / arounde.g. Stop fiddling about and do some work.commit v.do sth. wrong or illegale.g.It was disclosed in the media that this senior official had committed adultery with severalfemales.Collocations:commit sb. / sth. to sth.:order sb. to be put in a hospital or prisone.g. commit a man to prisoncommit sb. / oneself (to sth. / to doing sth.):say that sb. will definitely do sth. or must do sth.e.g. He has committed himself to support his brother’s children.Derivation:commitment (n.): a promise to do sth. or to behave in a particular waye.g.the government's commitment to public servicesIV. Sentences1．Coming home from an arduous day at the hospital, he would go straight to his yellow pad and write his tensions away. (Paragraph 3)Paraphrase:After a whole day’s intense work at the hospital, he w ould get rid of his tensions through writing.2．“Let it all hang out, and whatever form the sentences take will reflect the writer at his most natural.” (Paragraph 5) Paraphrase:Let the writer relax completely and the sentences he writes will show the most natural state of him.3．I have an unbroken record of missing the deeper meaning in any story, play or movie, and as for dance and mime, I have never had even a remote notion of what is being conveyed. (Paragraph 14)Paraphrase:I have nearly always failed to understand the hidden, implicit meaning expressed in any story, play or movie, and I do not have the slightest idea of what is being conveyed in dance and mime.4．Maybe I should take up surgery on the side. (Paragraph 16)Paraphrase:Perhaps I should take up surgery as a hobby.5．They sit down to commit an act of literature (paragraph 19)Paraphrase:They sit down to do some literary writing.Section Four Consolidation ActivitiesⅠ.Vocabulary1. Word Derivation1) drudge n. → drudge v. → drudgery n.⽆尽⽆休的﹑单调乏味的家务the endless drudgery of housework给那个公司打⼯⽆异于做苦⼒。
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.。
（最新）思科网络第一学期1-5章中文测试题及答案
ENetwork Chapter 2 - CCNA Exploration: 网络基础知识(版本 4.0) 1在封装过程中，数据链路层执行什么操作？不添加地址。
添加逻辑地址。
添加物理地址。
添加进程的端口号。
2TCP/IP 网络接入层有何作用？路径确定和数据包交换数据表、编码和控制可靠性、流量控制和错误检测详细规定构成物理链路的组件及其接入方法将数据段划分为数据包3数据链路层封装添加的报尾信息有何主要功能？支持差错校验确保数据按照顺序到达确保送达正确目的标识本地网络中的设备帮助中间设备进行处理和路径选择4请参见图。
下列哪组设备仅包含终端设备？A、C、DB、E、G、HC、D、G、H、I、JD、E、F、H、I、JE、F、H、I J5OSI 模型各层从最高层到最低层的正确顺序如何？物理层、网络层、应用层、数据链路层、表示层、会话层、传输层应用层、物理层、会话层、传输层网络层、数据链路层、表示层应用层、表示层、物理层、会话层、数据链路层、传输层、网络层应用层、表示层、会话层、传输层、网络层、数据链路层、物理层表示层、数据链路层、会话层、传输层、网络层、物理层、应用层6下列哪三项陈述是对局域网(LAN) 最准确的描述？（选择三项）LAN 通常位于一个地域内。
此类网络由由一个组织管理。
LAN 中的不同网段之间一般通过租用连接的方式连接。
此类网络的安全和访问控制由服务提供商控制。
LAN 为同一个组织内的用户提供网络服务和应用程序访问。
此类网络的每个终端通常都连接到电信服务提供商(TSP)。
7第4 层端口指定的主要作用是什么？标识本地介质中的设备标识源设备和目的设备之间的跳数向中间设备标识过该网络的最佳路径标识正在通信的源终端设备和目的终端设备标识终端设备内正在通信的进程或服务8以下哪种特征正确代表了网络中的终端设备？管理数据流发送数据流重新定时和重新传输数据信号确定数据传输路径9请参见图示。
哪个术语正确判断出了包含于绿色区域中的设备类型？源终端传输中间10OSI 模型哪两层的功能与TCP/IP 模型的网络接入层相同？（选择两项）网络层传输层物理层数据链路层会话层11请参见图示。
ERouting Final Exam - CCNA Exploration 路由协议和概念 (版本 4.0) (思科第二学期期末答案)
ERouting Final Exam - CCNA Exploration: 路由协议和概念 (版本 4.0) (思科第二学期期末答案)参加考试 - ERouting Final Exam - CCNA Exploration: 路由协议和概念 (版本 4.0)1.请参见图示。
哪一项是对连接到路由器 R1 的路由的最有效总结？198.18.0.0/16198.18.48.0/21198.18.32.0/22198.18.48.0/23198.18.49.0/23198.18.52.0/222.下列关于路由协议的陈述，哪三项是正确的？（选择三项。
）EIGRP 支持不等价负载均衡。
RIP 无法配置为允许无类路由。
OSPF 在多路访问链路上选举指定路由器。
RIP 不通告跳数超过 15 的路由。
EIGRP 使用广播流量与其邻居建立相邻关系。
OSPF 能够更迅速地收敛，因为在后继路由失效时，它能够在其拓扑表中找出可行后继路由。
3.请参见图示。
该网络正在运行 RIP 路由协议。
网络 10.0.0.0 突然断开。
下列有关此拓扑结构中路由器如何响应该事件的陈述中，哪一项是正确的？Router4 将在 30 秒之后的下一次定期更新中获知该失效路由。
在抑制计时器超时之前，水平分割将阻止 Router4 向 10.0.0.0 网络转发数据包。
Router5 将立即从路由表中清除这一失效路由。
Router5 将向 Router4 发送触发更新，其中网络 10.0.0.0 的度量为 16。
4.请参见图示。
根据图中所示的拓扑结构，要在 Paris 路由器上配置 EIGRP 需要使用哪三条命令？（选择三项。
）Paris(config)# router eigrp 100Paris(config)# router eigrpParis(config-router)# network 192.168.6.0Paris(config-router)# network 192.168.7.0Paris(config-router)# network 192.168.8.0Paris(config-router)# network 192.168.9.05.请参见图示。
CCNA_ESwitching _Chapter_1
1Which three features are commonly supported at the distribution layer of the Cisco hierarchical network model? (Choose thsecurity policiesPower over Ethernetswitch port securityquality of serviceLayer 3 functionalityend user access to network2Refer to the exhibit. What characteristic of hierarchical network designs is exhibited by having SW3 connected to both SW1scalabilitysecurityredundancymaintainability3Which hierarchical design model layer controls the flow of network traffic using policies and delineates broadcast domains routing functions between virtual LANs (VLANs)?accessdistributionnetworkcore4W hat is the likely impact of moving a conventional company architecture to a completely converged network?Local analog phone service can be completely outsourced to cost-effective providers.The Ethernet VLAN structure is less complex.A shared infrastructure is created resulting in a single network to manage.QoS issues are greatly reduced.There is less bandwidth competition between voice and video streams.5 A technician is attempting to explain Cisco StackWise technology to a client that is setting up three stackable switches. Whexplanation accurately describes StackWise technology?StackWise technology allows up to eight ports to be bound together to increase available bandwidth.StackWise technology allows the switch to deliver power to end devices by using existing Ethernet cabling.StackWise technology allows the switch capabilities and ports to be expanded by the addition of line cards.StackWise technology allows up to nine switches to be interconnected via the use of a fully redundant backplane.6W hich layer of the hierarchical design model provides a means of connecting devices to the network and controlling which allowed to communicate on the network?applicationaccessnetworkcore7Which feature supports higher throughput in switched networks by combining multiple switch ports?convergenceredundant linkslink aggregationnetwork diameter8W hich two characteristics are associated with enterprise level switches? (Choose two.)low port densityhigh forwarding ratehigh latency levelsupport link aggregationpredefined number of ports9Which layer of the hierarchical network design model is refered to as the high-speed backbone of the internetwork, where availability and redundancy are critical?access layercore layerdata-link layerdistribution layernetwork layerphysical layer10L ink aggregation should be implemented at which layer of the hierarchical network?core onlydistribution and coreaccess and distributionaccess, distribution, and core11 A network administrator is selecting a switch that will operate at the network core. Which three features should the switchoptimum network performance and reliability? (Choose three.)port securitysecurity policies10 Gigabit Ethernetquality of service (QoS)hot-swappable hardwarePower over Ethernet (PoE)12W hat statement best describes a modular switch?a slim-line chassisallows interconnection of switches on redundant backplanedefined physical characteristicsflexible characteristics13At which heirarchical layer are switches normally not required to process all ports at wire speed?core layerdistribution layeraccess layerentry layer14C onfiguring communication between devices on different VLANs requires the use of which layer of the OSI model?Layer 1Layer 3Layer 4Layer 515Refer to the exhibit. Beginning with HR servers and workstations, a network engineer is designing a new security structur network. Which set of policies adheres to the hierarchical network model design principles?Implement Layer 3 switching on S1 to reduce the packet processing load on D1 and D2. Install all security processin reduce network traffic load.Configure port security options on S1. Use Layer 3 access control features on D1 and D2 to limit access to the HR s the HR subnet.Move all HR assets out of the data center and connect them to S1. Use Layer 3 security functions on S1 to deny all out of S1.Perform all port access and Layer 3 security functions on C1.16A network technician is asked to examine an existing switched network. Following this examination, the technician makes recommendations for adding new switches where needed and replacing existing equipment that hampers performance. T is given a budget and asked to proceed. Which two pieces of information would be helpful in determining necessary port d switches? (Choose two.)forwarding ratetraffic flow analysisexpected future growthnumber of required core connectionsnumber of hubs that are needed in the access layer to increase performance17Which hierarchical design characteristic would be recommended at both the core and distribution layers to protect the net case of a route failure?PoEredundancyaggregationaccess lists18W hich two features are supported at all three levels of the Cisco three-layer hierarchical model? (Choose two.)Power over Ethernetload balancing across redundant trunk linksredundant componentsQuality of Servicelink aggregation19For organizations that are implementing a voice over IP solution, what functionality should be enabled at all three layers o hierarchical network?Power over Ethernetquality of serviceswitch port securityinter-VLAN routing20W hich layer of the OSI model does an access layer LAN switch use to make a forwarding decision?Layer 1Layer 2Layer 3Layer 4。
Solutions - Chapter 10
Solutions - Chapter 1010-1: Learning PythonOpen a blank file in your text editor and write a few lines summarizing what you’ve learned about Python so far. Start each line with the phrase In Python you can… Save the file as learning_python.txt in the same directory as your exercises fro mthis chapter. Write a program that reads the file and prints what you wrote three times. Print the contents once by reading in the entire file, once by looping over the file object, and once by storing the lines in a list and then working with them outside the with block.learning_python.txt:learning_python.py:Output:10-2: Learning CYou can use the replace() method to replace any word in a string with a different word. Here’s a quick example showing how to replace 'dog' with 'cat' in a sentence:Read in each line from the file you just created, learning_python.txt, and replace the word Python with the name of another language, such as C. Print each modified line to the screen.Output:You can use rstrip() and replace() on the same line. This iscalled chaining methods. In the following code the newline is stripped from the end of the line and then Python is replaced by C. The output is identical to the code shown above.10-3: GuestWrite a program that prompts the user for their name. When they respond, write their name to a file called guest.txt.Output:guest.txt:10-4: Guest BookWrite a while loop that prompts users for their name. When they entertheir name, print a greeting to the screen and add a line recording their visit in a file called guest_book.txt. Make sure each entry appears on a new line in the file.Output:guest_book.txt:10-5: Programming PollWrite a while loop that asks people why they like programming. Eachtime someone enters a reason, add their reason to a file that stores all the responses.Output:programming_poll.txt:10-6: AdditionOne common problem when prompting for numerical input occurs when people provide text instead of numbers. When you try to convert the input to an int, you’ll get a ValueError. Write a program that prompts for two numbers. Add them together and print the result. Catch the TypeError if either input value is not a number, and print a friendly error message. Test your program by entering two numbers and then by entering some text instead of a number.Output with two integers:Output with non-numerical input:10-7: Addition CalculatorWrap your code from Exercise 10-6 in a while loop so the user cancontinue entering numbers even if they make a mistake and enter text instead of a number.Output:10-8: Cats and DogsMake two files, cats.txt and dogs.txt. Store at least three names ofcats in the first file and three names of dogs in the second file. Write a program that tries to read these files and print the contents of the file to the screen. Wrap your code ina try-except block to catchthe FileNotFound error, and print a friendly message if a file is missing. Move one of the files to a different location on your system, and make sure the code in the except block executes properly.cats.txt:dogs.txt:cats_and_dogs.py:Output with both files:Output after moving cats.txt:10-9: Silent Cats and DogsModify your except block in Exercise 10-8 to fail silently if either file is missing.Output when both files exist:Output when cats.txt has been moved:10-11: Favorite NumberWrite a program that prompts for the user’s favorite number.Use json.dump() to store this number in a file. Write a separateprogram that reads in this value and prints the message, “I know your favorite number! It’s _____.”favorite_number_write.py:Output:favorite_number_read.py:Output:10-12: Favorite Number RememberedCombine the two programs from Exercise 10-11 into one file. If the number is already stored, report the favorite number to the user. If not, prompt for the user’s favorite number and store it in a file. Run the program twice to see that it works.Output, first run:Output, second run:10-13: Verify UserThe final listing for remember_me.py assumes either that the user has already entered their username or that the program is running for the first time. We should modify it in case the current user is not the person who last used the program.Before printing a welcome back message in greet_user(), ask the user if this is the correct username. If it’s not,call get_new_username() to get the correct username.Output:You might notice the identical else blocks in this versionof greet_user(). One way to clean this function up is to use an empty return statement. An empty return statement tells Python to leave the function without running any more code in the function. Here’s a cleaner version of greet_user():The return statement means the code in the function stops running after printing the welcome back message. When the username doesn’t exist, or the username is incorrect, the return statement is never reached. The second part of the function will only run whenthe if statements fail, so we don’t need an else block. Now the function prompts for a new username when either if statement fails. The only thing left to address is the nested if statements. This can be cleaned up by moving the code that checks whether the username iscorrect to a separate function. If you’re enjoying this exercise, you might try making a new function called check_username() and see if you can remove the nested if statement from greet_user().。
ERouting Final Exam CCNA Exploration路由协议和概念答案
ERouting Final Exam-CCNA Exploration:路由协议和概念(Version4.0)1.Which of the following are required when adding a network to the OSPF routing process configuration?network addressloopback addressa utonomous system numbersubnet maskwildcard maskarea ID2.Which of the following are primary functions of a router?(Choose two.)packet switchingmicrosegmentationdomain name resolutionpath selectionflow control3.Refer to the exhibit.When troubleshooting a network,it is important to interpret the output of various router commands.On the basis of the exhibit,which three statements are true?(Choose three.)The missing information for Blank1is the command show ip route.The missing information for Blank 1 is the command debug ip route.The missing information for Blank 2 is the number 100.The missing information for Blank2is the number120.The missing information for Blank 3 is the letter R.The missing information for Blank3is the letter C.4.Refer to the exhibit.Packets destined to which two networks will require the router to perform a recursive lookup?(Choose two.)10.0.0.0/864.100.0.0/16128.107.0.0/16172.16.40.0/24192.168.1.0/24192.168.2.0/245.When would the network administrator use the ip bandwidth-percent eigrp as-number percent command?when there is a low bandwidth connectionwhen the connection is on a shared mediumwhen the connection is serial instead of Ethernetwhen the link is always busy6.Refer to the exhibit.Cost for each path are shown.If all routers are configured to use OSPF,what would be the path of a packet sent from Router C to Router D if Router A was down?C-B-E-DC-B-A-D C-F-E-DC-F-B-A-D C-F-E-A-D7.What OSPF packet type is used to elect the designated router(DR)and backup designated router(BDR)on multiaccess networks?helloLSULSRDBDLSAck8.Refer to the exhibit.The hosts on the R1LAN are unable to access the Internet.What is incorrectly configured?the IP address of the Fa0/0 interface at R1the IP address of the S0/0/1 interface at R2the IP address of the S0/0/0interface at R1the subnet mask of the S0/0/1 interface at R29.Refer to the exhibit.Which summarization should R1use to advertise its networks to R2? 192.168.1.0/24192.168.0.0/24192.168.0.0/22192.168.1.0/2210.Refer to the exhibit.What are two of the routes added to the routing table of R1? (Choose two.)R 172.16.1.0/24 [120/1] via 192.168.3.0, 00:00:24, Serial0/0/0R192.168.1.0/24[120/1]via172.16.2.1,00:00:24,Serial0/0/1R 192.168.9.0/24 [120/1] via 172.16.1.2, 00:00:24, Serial0/0/0R192.168.100.0/24[120/1]via172.16.1.1,00:00:24,Serial0/0/0R 192.168.2.0/24 [120/1] via 172.16.1.2, 00:00:24, Serial0/0/011.A router boots and enters setup mode.What is the reason for this?The IOS image is corrupt.Cisco IOS is missing from flash memory.The configuration file is missing from NVRAM.The POST process has detected hardware failure.12.Refer to the exhibit.A router learns a route to the192.168.6.0network,as shown in the output of the show ip rip database command.However,upon running the show ip routecommand,the network administrator sees that the router has installed a different route to the192.168.6.0network learned via EIGRP.What could be the reason for the missing RIP route?Compared to RIP,EIGRP has a lower administrative distance.Compared to EIGRP, RIP has a higher metric value for the route.Compared to RIP, the EIGRP route has fewer hops.Compared to RIP, EIGRP has a faster update timer.13.All routers in a network are configured in a single OSPF area with the same priority value.No loopback interface has been set on any of the routers.Which secondary value will the routers use to determine the router ID?The highest MAC address among the active interfaces of the network will be used.There will be no router ID until a loopback interface is configured.The highest IP address among the active FastEthernet interfaces that are running OSPF will be used.The highest IP address among the active interfaces will be used.14.Refer to the exhibit.Routers R1and R2are directly connected via their serial interfaces and are both running the EIGRP routing protocol.R1and R2can ping the directly connected serial interface of their neighbor,but they cannot form an EIGRP neighbor adjacency.What action should be taken to solve this problem?Enable the serial interfaces of both routers.Configure EIGRP to send periodic updates.Configure the same hello interval between the routers. Configure both routers with the same EIGRP process ID.15.Refer to the exhibit.The interfaces of all routers are configured for OSPF area0.R3can ping R1,but the two routers are unable to establish a neighbor adjacency.What should the network administrator do to troubleshoot this problem?Check if the interfaces of the routers are enabled.Check the hello and dead intervals between the routers.Check the process ID of both routers.Check if CDP is enabled on all the routers.16.Refer to the exhibit.The hosts that are connected to R2are unable to ping the hosts that are connected to R1.How can this problem be resolved?Configure the router ID on both routers.Configure the R2router interfaces for area0.Configure a loopback interface on both routers.Configure the proper subnet masks on the router interfaces.17.Refer to the exhibit.The command ip route0.0.0.00.0.0.0S0/0/0is run on router R2. What are the two results of this command?(Choose two.)A static route will be updated in the routing table.The traffic from the Internet will be directed to R2.The traffic from the source network 172.16.0.0/22 will be blocked.The route will be specified as the default route for all networks not defined in the routing table.All the broadcasts will be forwarded via the S0/0/0 interface of R2.18.Refer to the exhibit.All routers are properly configured with default configurations and are running the OSPF routing protocol.The network is fully converged.A host on the 192.168.3.0/24network is communicating with a host on the192.168.2.0/24network.Which path will be used to transmit the data?The data will be transmitted via R3-R2.The data will be transmitted via R3-R1-R2.The traffic will be load-balanced between two paths — one via R3-R2, and the other via R3-R1-R2.The data will be transmitted via R3-R2, and the other path via R3-R1-R2 will be retained as the backup path.19.Refer to the exhibit.What is the meaning of the highlighted value120?It is the metric that is calculated by the routing protocol.It is the value that is used by the DUAL algorithm to determine the bandwidth for the link.It is the administrative distance of the routing protocol.It is the hold-down time, measured in seconds, before the next update.20.In a complex lab test environment,a router has discovered four paths to192.168.1.0/24 via the use of the RIP routing process.Which route will be installed in the routing table after the discovery of all four paths?R 192.168.1.0/24 [120/3] via 192.168.110.1, 00:00:17, Serial0/1/0R 192.168.1.0/24 [120/2] via 192.168.200.1, 00:00:17, Serial0/0/0R192.168.1.0/24[120/1]via192.168.100.1,00:00:17,Serial0/0/1R 192.168.1.0/24 [120/4] via 192.168.101.1, 00:00:17, Serial0/1/121.Refer to the exhibit.PC1is unable to access the Internet.What is the cause of the problem?An incorrect IP address is configured between the two routers. No static route is configured on Router2.A routing loop has occurred.No routing protocol is configured on either of the two routers.22.How does route poisoning prevent routing loops?New routing updates are ignored until the network has converged.Failed routes are advertised with a metric of infinity.A route is marked as unavailable when its Time to Live is exceeded.The unreachable route is cleared from the routing table after the invalid timer expires.23.Which statement is true about the metrics used by routing protocols?A metric is a value used by a particular routing protocol to compare paths to remote networks.A common metric is used by all routing protocols.The metric with the highest value is installed in the routing table.The router may use only one parameter at a time to calculate the metric.24.Which statement correctly describes a feature of RIP?RIP is a link-state routing protocol.RIP uses only one metric—hop count—for path selection.Advertised routes with hop counts greater than 10 are unreachable.Messages are broadcast every 10 seconds.25.Refer to the exhibit.OSPF is used for the routing protocol and all interfaces are configured with the correct IP addresses and subnet masks.During testing,it is found that router R1is unable to form an adjacency with R2.What is the cause of this problem?Both routers have been configured with incorrect router IDs.Both routers have been configured in different OSPF areas.Both routers have been configured with an incorrect network type.Both routers have been configured with different hello and dead intervals.26.A network administrator is in charge of two separate networks that share a single building.What device will be required to connect the two networks and add a common connection to the Internet that can be shared?hubrouteraccess pointEthernet switch27.Which network and mask combination requires the use of a classless addressing solution?10.32.0.0/11172.16.0.0/12192.168.0.0/24192.168.128.32/2728.A company is using static routes that are configured with an administrative distance of “1”on all routers in the network.The network administrator decides to introduce a dynamic routing protocol to reduce the manual configurations for the static routes.Which optionidentifies the correct procedure for the dynamic routing to take place in the network?The static routes and the dynamic routes will have the traffic alternate between them.The static routes will be automatically removed once the dynamic routing is configured.The static routes will be automatically updated with the next hop IP address once the dynamic routing is configured.The static routes must be manually removed from all routers in order for the dynamic routes to be installed in the routing table.29.Refer to the exhibit.Based on the partial output in the exhibit,why can users establish a console connection to this router without entering a password?The login command was not entered on the console line.The enable password should be an enable secret password.No username and password combination has been configured.Console connections cannot be configured to require users to provide passwords.30.Refer to the exhibit.When a static IP address is being configured on the host,what address should be used for the default gateway?10.1.1.110.1.1.2172.16.1.1192.168.1.131.Refer to the exhibit.The entire192.168.1.0network has been allocated to address hosts in the diagram.Utilizing VLSM with contiguous address blocks,which set of addresses andprefixes could be used to create an addressing solution with a minimum waste of IP addresses?Correct answer is image4.32.Refer to the exhibit.The network is configured for OSPF routing with default settings. The bandwidths have been configured correctly for each link.If the T1link between router A and router E fails,what path will a packet from router A take to reach the LAN attached to router F when the network has converged?A, B, C, FA, B, C, E, FA, D, G, E, FA,D,G,H,F33.Which candidate route has the longest match for a packet with a destination address of10.30.16.48?10.30.0.0/1610.30.15.0/2310.30.16.0/2410.30.16.32/2710.30.16.32/3034.Refer to the exhibit.The network is configured with RIPv2.However,network administrators notice that communication cannot be successfully completed from one LAN to another.A network administrator issues the show ip route command on the HQ router. Based on the output,what should be done to correct the problem?Disable the load balancing feature of RIPv2.Issue the no auto-summary command for RIPv2.Replace RIPv2 with EIGRP which supports VLSM.Make sure that the network statements include the correct subnet mask.35.Which multicast address does EIGRP use to send hello and updates packets?224.0.0.5224.0.0.6224.0.0.9224.0.0.1036.Refer to the exhibit.Why is the state of the serial0/0/0interface administratively down?An IP address has not been configured on the interface.The WIC was installed into the incorrect slot on the router.The default encapsulation on the interface has been modified.The no shutdown command has not been executed on the interface.37.Refer to the exhibit.How was the OSPF default gateway entry for R2determined? Default routes are automatically injected by OSPF into all advertisements.A static default gateway route is defined in the configuration of R2.The default-information originate command is applied on R1.The ISP defines the gateway of last resort and automatically passes it to R1 and R2.The ip default-gateway command is applied on R2.38.Refer to the exhibit.RIPv1has been properly configured on all routers in the network. However,users on LAN2have intermittent connectivity with the users on LAN1and LAN3. What is the cause of the problem?Both LAN networks are separated from router R2 with a variably subnetted Class C network 209.165.200.0/30.Neither router R1 nor router R3 has a static route configured that points to the variably subnetted 172.16.0.0/24 networks.Both routers R1and R3are sending the summarized172.16.0.0/16network to R2in their RIPv1routing updates.Both networks 172.16.1.0/24 and 172.16.100.0/24 are configured with a subnet mask different from the default classful mask.39.Which default EIGRP configuration must be modified to allow an EIGRP router to advertise subnets that are configured with VLSM?split horizonmetric K valuesautosummarizationhello and dead intervals40.What is a successor for a destination network in an EIGRP network?the next hop on the primary route with the largest feasible distance to the destinationthe next hop on the primary route with the smallest feasible distance to the destination41.Refer to the exhibit.Which route will be removed from the routing table if manual EIGRP summarization is disabled on the Serial0/0/0interface of Router3?0.0.0.0/0172.16.0.0/16172.16.1.0/24172.16.3.0/3042.Which port can be used for initial router configuration?AUXvty 0s0/0/0console43.Which two link-state routing protocol challenges does OSPF resolve through the election of a DR?(Choose two.)the extensive flooding of LSAs throughout the OSPF areathe excessive adjacencies when the number of routers increasesthe requirement for link-state database updates to be propagated between OSPF areasthe heavy CPU load that is imposed because each router must compute shortest paths by using the SPF algorithmthe requirement for each router to build a topological database of the internetwork to determinet he shortest paths between networks44.A routing table shows an EIGRP route to192.168.1.0/24with a metric of301440.What other term also describes this EIGRP metric value?feasible distancereported distancefeasible successorfeasibility condition45.Refer to the exhibit.The network administrator has run the following command on R1.R1(config)#ip route192.168.2.0255.255.255.0172.16.1.2What is the result of running this command?Traffic for network192.168.2.0is forwarded to172.16.1.2.This route is automatically propagated throughout the entire network.Traffic for all networks is forwarded to 172.16.1.2.The command invokes a dynamic routing protocol for 192.168.2.0.46.Refer to the exhibit.What will happen if interface Serial0/0/1goes down on Router1? The Dijkstra algorithm will calculate the feasible successor.DUAL will query neighbors for a route to network192.168.1.0.Neighbor 172.16.3.2 will be promoted to the feasible successor.Traffic destined to the 192.168.1.0 network will be dropped immediately due to lack of a feasible successor.47.Refer to the exhibit.A network administrator is accessing router R1from the console port.Once the administrator is connected to the router,which password should the administrator enter at the R1>prompt to access the privileged EXEC mode?Cisco001Cisco123Cisco789Cisco90148.Refer to the exhibit.Which option will provide the configuration that is needed for router R1to dynamically learn routes to the192.168.100.16/28,192.168.100.32/28,and 192.168.100.48/28subnetworks?with static routeswith a routed protocolwith a routing protocolwith directly connected routes49.Refer to the exhibit.What will happen when the router reloads?It will boot into ROMMON mode.It will ignore the start-up configuration file.It will look for the start-up configuration file on the TFTP server.It will attempt to load the start-up configuration file that is stored in NVRAM.50.On a router,which actions can be performed in user mode?perform password recoverymake global configuration changesview status of various router functionsmake changes to a specified interface。
CCNA_ERouting_Chapter_2
1窗体顶端Which address can be used to summarize networks 172.16.0.0/24 thru 172.16.7.0/24?172.16.0.0/21172.16.1.0/22172.16.0.0 255.255.255.248172.16.0.0 255.255.252.0窗体底端2窗体顶端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.窗体底端3窗体顶端Refer to the exhibit. Which static route should be configured on Router1 so that host A will be able to reach h 172.16.0.0 network?ip route 192.168.0.0 172.16.0.0 255.255.0.0ip route 172.16.0.0 255.255.0.0 192.168.0.1ip route 172.16.0.0 255.255.0.0 S0/0/1ip route 172.16.0.0 255.255.0.0 S0/0/0窗体底端4窗体顶端Refer to the exhibit. Which set of commands will configure static routes that will allow the WinterPark and th 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 s0/1WinterPark(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 s0/1WinterPark(config)# ip route 172.191.67.0 255.255.255.0 192.168.146.1WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2WinterPark(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 s0/0窗体底端5窗体顶端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 m to use that route.6Refer to the exhibit. A company network engineer is assigned to establish connectivity between thenetworks so that hosts on the 10.1.1.0/24 subnet can contact hosts on the 10.1.2.0/24 subnet. The engineer to use only static routing for these company routers. Which set of commands will establish connectivity bet Ethernet networks?R1(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.1R2(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.2R1(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.2R2(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.1R1(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.2R2(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.1R1(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.1R2(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.2R1(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 10.1.1.17Why is it advisable to enter a next-hop IP address when creating a static route whose exit interface is network?Adding the next-hop address eliminates the need for the router to do any lookups in the routingforwarding a packet.In a multi-access network, the router cannot determine the next-hop MAC address for the Ethernet franext-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 default8窗体顶端What two devices are responsible for converting the data from the WAN service provider into a form acceptable b (Choose two).the serial port of the routera modema switchthe ethernet port of the routera CSU/DSU devicea DTE device9窗体顶端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.窗体底端10窗体顶端Hosts on two separate subnets cannot communicate. The network administrator suspects a missing route in one o tables. Which three commands can be used to help troubleshoot Layer 3 connectivity issues? (Choose three.)pingshow arptracerouteshow ip routeshow controllersshow cdp neighbor11Refer 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.窗体底端12窗体顶端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.13窗体顶端A router has one static route configured to each destination network. Which two scenarios would require an admalter 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.The remote destination network interface has to be down for 15 minutes of maintenance.A topology change occurs where the existing next-hop address or exit interface is not accessible.14窗体顶端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 0administrative distance of 0 and metric of 1administrative distance of 1 and metric of 0administrative distance of 1 and metric of 1窗体底端15窗体顶端Which of the following are displayed by the Router# show cdp neighbors command? (Choose three.)loadplatformreliabilityholdtimelocal interface16The 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 router is using serial 0/0.No clock rate has been set.窗体底端17窗体顶端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 resor S0/2.窗体底端18窗体顶端Refer to the exhibit. What two commands are required to provide connectivity between the 192.168.1.0 and 10.0.without requiring recursive lookup? (Choose two.)A(config)# ip route 10.0.0.0 255.0.0.0 s 0/1/0A(config)# 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 s 0/0/0B(config)# ip route 192.168.1.0 255.255.255.0 s 0/0/0B (config)# ip route 192.168.1.0 255.255.255.0 172.16.40.1B(config)# ip route 192.168.1.0 255.255.255.0 s 0/1/019窗体顶端Refer to the exhibit. What two commands will change the next-hop address for the 10.0.0.0/8 network from 1 192.168.1.2? (Choose two.)A(config)# no network 10.0.0.0 255.0.0.0 172.16.40.2A(config)# no ip address 10.0.0.1 255.0.0.0 172.16.40.2A(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 s0/0/0A(config)# ip route 10.0.0.0 255.0.0.0 192.168.1.2窗体底端20窗体顶端A network administrator enters the following command into Router1: ip route 192.168.0.0 255.255.255.0 S0/1/0.receives a packet that is destined for 192.168.0.22/24. After finding the recently configured static route in the routin does Router1 do next to process the packet?drops the packet because the destination host is not listed in the routing tablelooks up the MAC address of the S0/1/0 interface to determine the destination MAC address of the new frameperforms a recursive lookup for the IP address of the S0/1/0 interface before forwarding the packetencapsulates the packet into a frame for the WAN link and forwards the packet out the S0/1/0 interface21Which piece of information is available from examining the output of the command show ip interface brief?Interface speed and duplexInterface MTUErrorsInterface MAC addressInterface IP address。
CCNA ENetwork Chapter 9
ENetwork Chapter 9 - CCNA Exploration: Network(2009-05-10 12:32:43)转载分类：CCNA.CISCO.ANSWERS标签：itPosted by Space on Sunday, May 10, 20091In the graphic, Host A has reached 50% completion in sending a 1 KB Ethernet frame to Host D when Host B wishes to transmit its own frame to Host C. What must Host B do?Host B can transmit immediately since it is connected on its own cable segment.Host B must wait to receive a CSMA transmission from the hub, to signal its turn.Host B must send a request signal to Host A by transmitting an interframe gap.**Host B must wait until it is certain that Host A has completed sending its frame.2 Ethernet operates at which layers of the OSI model? (Choose two.)Network layerTransport layer**Physical layerApplication layerSession layer**Data-link layer3 Which of the following describe interframe spacing? (Choose two.)**the minimum interval, measured in bit-times, that any station must wait before sending another framethe maximum interval, measured in bit-times, that any station must wait before sending another framethe 96-bit payload padding inserted into a frame to achieve a legal frame sizethe 96-bit frame padding transmitted between frames to achieve proper synchronization**the time allowed for slow stations to process a frame and prepare for the next framethe maximum interval within which a station must send another frame to avoid being considered unreachable4 What three primary functions does data link layer encapsulation provide? (Choose three.)**addressing**error detection**frame delimitingport identificationpath determinationIP address resolution5 When a collision occurs in a network using CSMA/CD, how do hosts with data to transmit respond after the backoff period has expired?**The hosts return to a listen-before-transmit mode. <—The hosts creating the collision have priority to send data.The hosts creating the collision retransmit the last 16 frames.The hosts extend their delay period to allow for rapid transmission.6 What are three functions of the upper data link sublayer in the OSI model? (Choose three.)recognizes streams of bits**identifies the network layer protocol**makes the connection with the upper layersidentifies the source and destination applications**insulates network layer protocols from changes in physical equipmentdetermines the source of a transmission when multiple devices are transmitting7 What does the IEEE 802.2 standard represent in Ethernet technologies?MAC sublayerPhysical layer**Logical Link Control sublayerNetwork layer8 Why do hosts on an Ethernet segment that experience a collision use a random delay before attempting to transmit a frame?A random delay is used to ensure a collision-free link.A random delay value for each device is assigned by the manufacturer.A standard delay value could not be agreed upon among networking device vendors.**A random delay helps prevent the stations from experiencing another collision during the transmission.98Refer to the exhibit. Which option correctly identifies content that the frame data field may contain?preamble and stop framenetwork layer packetphysical addressingFCS and SoF10Host A has an IP address of 172.16.225.93, a mask of 255.255.248.0, and a default gateway of 172.16.224.1. Host A needs to to a new host whose IP is 172.16.231.78. Host A performs the ANDing operation on its address and subnet mask. What two thin (Choose two.)Host A will get a result of 172.16.224.0 from the AND process.Host A will send on to the media a broadcast frame that contains the packet.Host A will broadcast an ARP request for the MAC of the host 172.16.231.78.Host A will change the destination IP of the packet to 172.16.224.1 and forward the packet.Host A will encapsulate the packet in a frame with a destination MAC that is the MAC address associated with 172.16.224.11 Which of the following is a drawback of the CSMA/CD access method?**Collisions can decrease network performance.It is more complex than non-deterministic protocols.Deterministic media access protocols slow network performance.CSMA/CD LAN technologies are only available at slower speeds than other LAN technologies.12 Ethernet operates at which layer of the TCP/IP network model?applicationphysicaltransportinternetdata link**network access10Ethernet operates at which layers of the OSI model? (Choose two.)Network layerTransport layerPhysical layerApplication layerSession layerData-link layer13 What is the primary purpose of ARP?translate URLs to IP addresses**resolve IPv4 addresses to MAC addressesprovide dynamic IP configuration to network devicesconvert internal private addresses to external public addresses14Refer to the exhibit. The switch and workstation are administratively configured for full-duplex operation. Which statement accurately reflects the operation of this link?**No collisions will occur on this link.Only one of the devices can transmit at a time.The switch will have priority for transmitting data.The devices will default back to half duplex if excessive collisions occur.15Refer to the exhibit. Host_A is attempting to contact Server_B. Which statements correctly describe the addressing Host_A will generate in the process? (Choose two.)A packet with the destination IP of Router_B.A frame with the destination MAC address of Switch_A.A packet with the destination IP of Router_A.**A frame with the destination MAC address of Router_A.**A packet with the destination IP of Server_B.A frame with the destination MAC address of Server_B.16 Which statements correctly describe MAC addresses? (Choose three.)dynamically assigned**copied into RAM during system startuplayer 3 address**contains a 3 byte OUI**6 bytes long32 bits long17 Which two features make switches preferable to hubs in Ethernet-based networks? (Choose two.)reduction in cross-talk**minimizing of collisionssupport for UTP cabling**division into broadcast domainsincrease in the throughput of communications18 What are the two most commonly used media types in Ethernet networks today? (Choose two.)**coaxial thicknetcopper UTPcoaxial thinnetoptical fiber**shielded twisted pair19 Convert the binary number 10111010 into its hexadecimal equivalent. Select the correct answer from the list below.8590**BAA1B31C20 After an Ethernet collision, when the backoff algorithm is invoked, which device has priority to transmit data?the device involved in the collision with the lowest MAC addressthe device involved in the collision with the lowest IP address**any device in the collision domain whose backoff timer expires first those that began transmitting at the same time。
ccna第二学期练习答案
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。
）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Sydney(config-if)#Sydney(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。
CCNA_ENetwork_Chapter_2
ENetwork Chapter 2 - CCNA Exploration ：Network(2009-05-10 11:32:50)分类：CCNA.CISCO.ANSWERS标签：itPosted by Space on Sunday, May 10, 20091 What are the key functions of encapsulation? (Choose three.)*allows modification of the original data before transmission*identifies pieces of data as part of the same communication*enables consistent network paths for communicationensures that data pieces can be directed to the correct receiving end deviceenables the reassembly of complete messagestracks delay between end devices2 Which layer encapsulates the segment into packets?physicaldata link*networktransport3 Which three statements best describe a Local Area Network (LAN)? (Choose three.) *A LAN is usually in a single geographical area.*The network is administered by a single organization.The connection between segments in the LAN is usually through a leased connection.The security and access control of the network are controlled by a service provider.*A LAN provides network services and access to applications for users within a common organization.Each end of the network is generally connected to a Telecommunication Service Provider (TSP).4 What is the proper order of the layers of the OSI model from the highest layer to the lowest layer?physical, network, application, data link, presentation, session, transportapplication, physical, session, transport, network, data link, presentationapplication, presentation, physical, session, data link, transport, network*application, presentation, session, transport, network, data link, physicalpresentation, data link, session, transport, network, physical, application5 During the encapsulation process, what occurs at the data link layer?No address is added.The logical address is added.*The physical address is added.The process port number is added.6 Select the statements that are correct concerning network protocols. (Choose three.)define the structure of layer specific PDU's*dictate how to accomplish layer functions*outline the functions necessary for communications between layerslimit hardware compatibility*require layer dependent encapsulationseliminate standardization among vendors7Refer to the exhibit. Which three labels correctly identify the network types for the network segments that are shown? (Choose three.)Network A -- WAN*Network B -- WAN*Network C -- LANNetwork B -- MANNetwork C -- WAN*Network A -- LAN8 Which statements correctly identify the role of intermediary devices in the network? (Choose three.)*determine pathways for datainitiate data communications*retime and retransmit data signalsoriginate the flow of data*manage data flowsfinal termination point for data flow9 Which two layers of the OSI model have the same functions as the TCP/IP model Network Access Layer? (Choose two.)* NetworkTransport* PhysicalData LinkSession10 What can be identified by examining the network layer header?the destination device on the local media* the path to use to reach the destination hostthe bits that will be transferred over the mediathe source application or process creating the data11Refer to the exhibit. "Cell A" at IP address 10.0.0.34 has established an IP session with "IP Phone 1" at IP address 172.16.1.103. Based upon the graphic, which device type best describes the function of wireless device "Cell A?"the destination device* an end devicean intermediate devicea media device12Refer to the exhibit. Which set of devices contains only end devices?* A, C, DB, E, G, HC, D, G, H, I, JD, E, F, H, I, JE, F, H, I, J13 What is the purpose of the TCP/IP Network Access layer?* path determination and packet switchingdata representation, encoding, and controlreliability, flow control, and error detectiondetailing the components that make up the physical link and how to access it the division of segments into packets14 What device is considered an intermediary device?file serverIP phonelaptopprinter* switch15 What is a PDU?corruption of a frame during transmissiondata reassembled at the destinationretransmitted packets due to lost communication* a layer specific encapsulation16 What is the primary purpose of Layer 4 port assignment?to identify devices on the local mediato identify the hops between source and destinationto identify to the intermediary devices the best path through the networkto identify the source and destination end devices that are communicating* to identify the processes or services that are communicating within the end devices17 What is a primary function of the trailer information added by the data link layer encapsulation?* supports error detectionensures ordered arrival of dataprovides delivery to correct destinationidentifies the devices on the local networkassists intermediary devices with processing and path selection18Refer to the exhibit. Which term correctly identifies the device type that is included in the green area?sourceendtransfer* intermediary19Refer to the exhibit. Which networking term describes the data interleaving process represented in the graphic?pipingPDUstreaming* multiplexingencapsulation20 Which characteristic correctly refers to end devices in a network?manage data flowsoriginate data flowretime and retransmit data signalsdetermine pathways for data21Refer to the exhibit. What type of network is shown?WANMAN* LANWLAN。
CCNA_ESwitching _Chapter_2_答案
1请参见图示。
当主机 1 试图发送数据时会发生什么情况？来自主机 1 的帧会导致接口关闭。
会丢弃来自主机 1 的帧，且不发送日志消息。
来自主机 1 的帧会在运行配置中创建MAC 地址条目。
来自主机 1 的帧会删除地址表中的所有MAC 地址条目。
2启动配置存储在哪里？DRAMNVRAMROMstartup-config.text3下列关于执行模式口令的说法中哪两项正确？（选择两项。
）使能加密口令命令采用明文存储所配置的口令。
使能加密口令命令的安全性比使能口令高。
使能口令和使能加密口令用于保护对特权执行模式的访问。
需要采用命令service password-encryption来加密使能加密口令。
最佳做法是要求同时配置并使用使能口令和使能加密口令。
4请参见图示。
网络管理员尝试通过安全外壳连接到Switch1 但失败了。
最可能的原因是什么？配置的vty 线路不正确默认网关地址不正确安全外壳版本不兼容vty 线路被配置为只允许Telnet 连接5请参见图示。
图中显示网络中存在多少个冲突域？1246786请参见图示。
图中显示了show running-config命令的部分输出。
此交换机的使能口令是"cisco"。
从图中所示的输出可得默认情况下会加密使能口令。
所有加密口令均采用MD5 哈希算法加密。
在此配置中，已配置的所有线路模式口令都会被加密。
此行代表最安全的特权执行模式口令。
7请参见图示。
如果SW1 的MAC 地址表为空，SW1 会对从PC_A 发送到PC_C 的帧采取以下哪项操作？SW1 会丢弃该帧。
SW1 会将该帧从除端口Fa0/1 之外的所有端口泛洪出去。
SW1 会将该帧从该交换机上除端口Fa0/23 和Fa0/1 之外的所有端口泛洪出去。
SW1 会采用CDP 协议同步两台交换机的MAC 地址表，然后将帧转发到SW2 上的所有端口。
8可采用哪两种方法来使交换机不易受MAC 地址泛洪、CDP 攻击和Telnet 攻击等攻击的影响？（选择两项。
CCNA_ERouting_Chapter_5
1Which of the following is considered a limitation of RIP v1?RIP v1 does not send subnet mask information in its updates.RIP v1 is not widely supported by networking hardware vendors.RIP v1 consumes excessive bandwidth by multicasting routing updates using a Class D address.RIP v1 requires enhanced router processors and extra RAM to function effectively.RIP v1 does not support load balancing across equal-cost paths.RIP v1 authentication is complicated and time-consuming to configure.2Refer to the exhibit. A network consists of multiple routers. What can be verified when the show ip protocols command is of the routers in the network?whether all routes in the network have been properly added to the routing tablerouting protocol configuration in use for IP on this routeroperational status of routing protocols in use on all routers in the networkrouting metric of each network that is listed in the routing table3Refer to the exhibit. All routers in the exhibit are running RIP v1. The network administrator issues the show ip route commA. What routes would appear in the routing table output if the network is converged? (Choose two).R 192.168.2.0/24 [120/1]C 192.168.2.0/24 [120/1]R 10.10.3.0/24 [120/0]C 10.10.3.0/24 [120/1]R 10.10.1.0/24 [120/2]R 10.10.1.0/24 [120/3]4Which of the following would be the correct command sequence to enable RIP on Router B for all connected networks?RouterB# router ripRouterB(router)# network 210.36.7.0 RouterB(router)# network 220.17.29.0 RouterB(router)# network 211.168.74.0RouterB(config)# router ripRouterB(config-router)# network 198.16.4.0RouterB(config-router)# network 211.168.74.0RouterB(config-router)# network 199.84.32.0RouterB(config)# configure router ripRouterB(config-router)# network 210.36.7.0RouterB(config-router)# network 199.84.32.0RouterB(config-router)# network 211.168.74.0RouterB(config)# router ripRouterB(config-router)# network 198.16.4.0RouterB(config-router)# network 210.36.7.0RouterB(config-router)# network 211.168.74.0RouterB(config)# router ripRouterB(config-router)# network 198.16.4.0RouterB(config-router)# network 210.36.7.0RouterB(config-router)# network 220.17.29.05Which command will display RIP activity as it occurs on a router?debug ip ripshow ip routeshow ip interfaceshow ip protocolsdebug ip rip configshow ip rip database6W hich command or set of commands will stop the RIP routing process?RouterB(config)# router ripRouterB(config-router)# shutdownRouterB(config)# router ripRouterB(config-router)# network no 192.168.2.0RouterB(config)# no router ripRouterB(config)# router no rip7Refer to the exhibit. RIPv1 is running on all three routers. All interfaces have been correctly configured with addresses in th ranges that are shown. Which route would you see in the routing table on router CHI if the routers are configured with the co are displayed in the exhibit?192.168.0.4/30192.168.0.0/24192.168.0.0/16192.168.0.32/278T he 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?31220301209Refer to the exhibit. All routers are configured with valid interface addresses in the indicated networks and are running RIP network is converged. Which routes are present in the routing tables?All routers have all routes in their routing table.All routers have all /30 routes, but do not have /24 routes in their routing table.All routers have all /30 routes. Routers A and E also have some of the /24 routes in their routing table.All routers have all /30 routes. Routers B and D also have some of the /24 routes in their routing table.Routers A and E have all routes. Routers B and D have only /30 routes in their routing table.Routers A and E have only /24 routes. Routers B and D have only /30 routes in their routing table.10W hat are three characteristics of the RIPv1 routing protocol? (Choose three.)supports the use of VLSMuses hop count as a metricconsiders a metric of 16 as infinityhas an administrative distance of 110 by defaultincludes the destination IP address and subnet mask in routing updatescalculates metrics using the Bellman Ford algorithm11What will happen if an interface IP address is entered for the address portion of the network command in a RIPv1 configu of a network address?The router will reject the command.A route to the host address will be added to outgoing RIP updates.A route to the host address will be added to the routing table.All interfaces in the same classful network as the configured address will be included in the RIPv1 routing process.12Refer to the exhibit. The Ethernet interface on Router2 goes down and the administrator notices that the route is still valid table of Router1. How much longer will it take for Router1 to mark the route invalid by setting the metric to 16?30 seconds90 seconds155 seconds180 seconds255 seconds13Refer to the exhibit. The network that is shown is running RIPv1. The 192.168.10.0/24 network was recently added and w end users. What command or set of commands should be entered on Router1 to prevent RIPv1 updates from being sent to devices on the new network while still allowing this new network to be advertised to other routers?Router1(config-router)# no router ripRouter1(config-router)# network 192.168.10.0Router1(config-router)# no network 192.168.10.0Router1(config-router)# passive-interface fastethernet 0/0Router1(config-router)# passive-interface serial 0/0/014Refer to the exhibit. All routers that are shown are running the RIP routing protocol. All unknown IP traffic must be forward What router or set of routers are recommended to have both a default route and the default-information originate comm implement this forwarding policy?only Router1only the gateway routerall routers in the networkonly the routers with LANs needing Internet access15Refer to the exhibit. Router1 and Router2 are running the RIPv1 protocol. The network administrator configures the comm10.1.0.0 on Router1. What network will Router1 advertise to Router2?10.1.0.0/1610.1.0.0/810.0.0.0/1610.0.0.0/816W hat is the default update period in seconds for the RIP routing protocol?10121520306017Refer to the exhibit. What can be concluded from the routing table output of router B?A static default route has been configured on B.The default-information originate command has been entered on A.All traffic that is destined for 192.168.1.1 will be sent to address 0.0.0.0.18W hich two statements are true regarding the characteristics of RIPv1? (Choose two).It is a distance vector routing protocol.It advertises the address and subnet mask for routes in routing updates.The data portion of a RIP message is encapsulated into a TCP segment.The data portion of a RIP message is encapsulated into a UDP segment.It broadcasts updates every 15 seconds.It allows a maximum of 15 routers in the routing domain.19Refer to the exhibit. Router1 is running RIPv1. What command was entered into Router1 to configure the gateway of last re no auto-summaryip default-network 0.0.0.0ip default-gateway 10.0.0.0ip route 0.0.0.0 0.0.0.0 S0/0/1。
CCNA ENetwork Chapter 11
ENetwork Chapter 11 - CCNA Exploration: Network(2009-05-10 12:35:51)转载分类：CCNA.CISCO.ANSWERS标签：itPosted by Space on Sunday, May 10, 20091Refer to the exhibit. What command will place the router into the correct mode to configure an appropriate interface to connect to a LAN?UBAMA# configure terminalUBAMA(config)# line vty 0 4UBAMA(config)# line console 0UBAMA(config)# interface Serial 0/0/0**UBAMA(config)# interface FastEthernet 0/12In a Cisco router, when do changes made to the running-configuration take effect?after a system restartas the commands are enteredwhen logging off the system**when the configuration is saved to the startup-configuration3Refer to the exhibit. A technician applies the configuration in the exhibit to a clean router. To verify the configuration, the technician issues the show running-config command in the CLI session with the router. What lines should the technician expect to see in the router output from the show running-config command?enable password classline console 0password ccnaenable secret ciscoenable password classline console 0password ccnaenable secret 5 $1$v0/3$QyQWmJyT7zCa/yaBRasJm0enable password classline console 0password ccnaenable secret ciscoenable password 7 14141E0A1F17line console 0password 7 020507550A**enable secret 5 $1$v0/3$QyQWmJyT7zCa/yaBRasJm0enable password 7 14141E0A1F17line console 0password 7 020507550AAUXEthernet**ConsoleTelnetSSH5Refer to the exhibit. A network administrator on HostA has problems accessing the FTP server. Layer three connectivity testing was successful from HostA to the S1 interface of RouterB. Which set of commands will allow the network administrator to telnet to RouterB and run debug commands?RouterB(config)# enable secret classRouterB(config)# line vty 0 4RouterB(config-if)# loginRouterB(config)# enable secret classRouterB(config)# line vty 0 2RouterB(config-vty)# password ciscoRouterB(config-vty)# login**RouterB(config)# enable secret classRouterB(config)# line vty 0RouterB(config-line)# password ciscoRouterB(config-line)# loginRouterB(config)# enable secret classRouterB(config)# line aux 0RouterB(config-line)# password ciscoRouterB(config-line)# loginRouterB(config)# enable secret classRouterB(config)# line aux 0RouterB(config-vty)# password ciscoRouterB(config-vty)# login6Users in the network are experiencing slow response time when doing file transfers to a remote server. What command could be issued to determine if the router has experienced any input or output errors?show running-configshow startup-config**show interfacesshow ip routeshow versionshow memory7Refer to the exhibit. Which names correctly identify the CLI mode represented by the prompt for Switch-East4#? (Choose two.)line configuration modeuser executive mode**global configuration modeprivileged executive modeinterface configuration mode**enable mode8What command is used to change the default router name to Fontana?Router# name FontanaRouter# hostname FontanaRouter(config)# name Fontana**Router(config)# hostname Fontana9The 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 201.100.53.2 255.255.255.0**Sydney(config-if)# no shutdownSydney(config-if)# ip address 201.100.53.1 255.255.255.224**Sydney(config-if)# clock rate 56000Sydney(config-if)# ip host Melbourne 201.100.53.210Refer to the exhibit. The output is shown for the show ip route command executed on Router A. What does the IP address 192.168.2.2 represent?Gateway for the 192.168.1.0 networkGateway for the 192.168.3.0 networkIP assigned to the serial port on Router A**IP assigned to the serial port on Router B11Refer to the exhibit. What additional command is required to allow remote access to this switch? NA-SW1(config-if)# no shutdownNA-SW1(config)# enable password password**NA-SW1(config)# ip default-gateway addressNA-SW1(config-if)# description descriptionshow flashshow NVRAM**show startup-config**show running-configshow version13Which three terms correctly define the forms of help available within the Cisco IOS? (Choose three.)hot keys**context-checkcontext-sensitive**structured checkcommand override**command syntax check14Refer to the exhibit. A student is responsible for the IP addressing, configuration and connectivity testing of the network shown in the graphic. A ping from host B to host C results in a destination unreachable but a ping from host B to host A was successful. What two reasons could account for this failure based on the graphic and partial router output for the Dallas router? (Choose two.) The host A is turned off.The Fa0/0 interface on Dallas is shutdown.The LAN cable is disconnected from host B.**The S0/0/1 IP address of Dallas is improperly configured.**The Fa0/0 interface on Dallas is in a different subnet than host B.The clock rate is missing on the serial link between Dallas and NYC.**Ctrl-CCtrl-PCtrl-RCtrl-Shift-6Ctrl-Z16The connection between routers B and C has been successfully tested. However, after rebooting router C, the administrator noticed the response time between networks 10.10.3.0 and 10.10.4.0 is slower. Ping between the two routers is successful. A trace route indicates three hops from router B to router C. What else can be done to troubleshoot the problem?Ping router B S0/1 connection from router C.Trace the connection between router B to router C S0/1.Issue a show ip route command in router B to verify routing is enabled.**Issue a show interfaces command on router C.RAMROM**FlashNVRAMchosen? Telnet Console AUX **SSH。
CCNA Exploration 路由协议和概念 (版本 4.0)
3请参见图示。
该网络正在运行 RIP 路由协议。
网络 10.0.0.0 突然断开。
下列有关此拓扑结构中路由器如何响应该事件的陈述中，哪一项是正确的？a Router4 将在 30 秒之后的下一次定期更新中获知该失效路由。
b 在抑制计时器超时之前，水平分割将阻止 Router4 向 10.0.0.0 网络转发数据包。
c Router5 将立即从路由表中清除这一失效路由。
d Router5 将向 Router4 发送触发更新，其中网络 10.0.0.0 的度量为 16。
4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。
）a路由器修改 TTL 字段，将其值减 1。
b路由器将源 IP 更改为送出接口的 IP。
c路由器保持相同的源 IP 和目的 IP。
d路由器将源物理地址更改为送出接口的物理地址。
e路由器将目的 IP 更改为送出接口的 IP。
f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。
5请参见图示。
网络管理员在 Router1 上发出no ip classless命令。
当 Router1 收到目的地为 192.168.0.26 主机的数据包时，会发生怎样的转发行为？a数据包将被丢弃。
b数据包将转发到“最后选用网关”c数据包将与 192.168.0.0 网络匹配，并从 Serial 0/0 转发出去。
d数据包将与 192.168.0.8 子网形成最精确匹配，并从 Serial 0/1 转发出去。
6路由器通过静态路由和动态路由过程获知网络。
它会使用哪条路由来到达网络192.168.168.0？A. 192.168.168.0/24 [90/2195456] via 192.168.200.1, 00:00:09, Ethernet0Ob. 192.168.168.0/24 [110/1012] via 192.168.200.1, 00:00:22, Ethernet0Rc. 192.168.168.0/24 [120/1] via 192.168.200.1, 00:00:17, Ethernet0Sd. 192.168.168.0/24 [1/0] via 192.168.200.17向 OSPF 路由过程配置中添加网络时，需要下列哪几项？（选择三项。
CCNA ENetwork Chapter 10
ENetwork Chapter 10 - CCNA Exploration: Network(2009-05-10 12:34:20)转载分类：CCNA.CISCO.ANSWERS标签：itPosted by Space on Sunday, May 10, 2009这份分数相对较少75%1Refer to the exhibit. A student working in the lab selects a cable that is wired as shown. Which connection types can successfully be made with this cable? (Choose two.)connecting a PC to a router’s c onsole port**connecting two routers together via their fast ethernet ports**connecting two switches together at gigabit speedsconnecting a PC to a switch at Gigabit Ethernet speedsconnecting two devices with the same interface type at Fast Ethernet speeds2Which three statements are true about the role of routers in the network? (Choose three.) They propagate broadcasts.They enlarge collision domains.**They segment broadcast domains.They interconnect different network technologies.**Each router interface requires a separate network or subnet.**They maintain a common frame format between LAN and WAN interfaces.3Refer to the exhibit. A network administrator has decided to use packet capture software to uate all traffic from the student subnet on the way to the Internet. To ensure that all packets are captured, what network device should be used to connect the monitoring station to the network between R1 and R2?router**hubswitchwireless access point4A network administrator is required to use media in the network that can run up to 100 meters in cable length without using repeaters. The chosen media must be inexpensive and easily installed. The installation will be in a pre-existing building with limited cabling space. Which type of mediawould best meet these requirements?**STPUTPcoaxialsingle-mode fibermultimode fiberHosts B and C are in the same subnet.**Five broadcast domains are present.**Host B is using a crossover cable to connect to the router.Four broadcast domains are present.**Five networks are shown.Host B is using a rollover cable to connect to the router.6Which three types of connectors are commonly associated with Cisco’s V.35 serial cables? (Choose three.)RJ 11**DB 60**Winchester 15 pinDB 9**smart serialRJ 457How many host addresses may be assigned on each subnetwork when using the 130.68.0.0 network address with a subnet mask of 255.255.248.0?30256**20462048409440968Refer to the exhibit. Based on the IP configuration shown, what would be the result of Host A and Host B attempting to communicate outside the network segment?both host A and B would be successful**host A would be successful, host B would failhost B would be successful, host A would failboth Host A and B would fail192.168.1.1192.168.2.1192.168.2.2192.168.3.1**192.168.3.54Segment 1 uses backbone cabling.**Segment 1 uses a patch cable.Segment 3 uses patch cabling.Segment 3 uses vertical cabling.**Segment 3 uses horizontal cabling.**Segment 4 uses vertical cabling.11A company is planning to subnet its network for a maximum of 27 hosts. Which subnet mask would provide the needed hosts and leave the fewest unused addresses in each subnet? 255.255.255.0255.255.255.192**255.255.255.224255.255.255.240255.255.255.24812Refer to the exhibit. A student is setting up a home network primarily used for extensive file transfers, streaming video, and gaming. Which network device is best suited to these types of activities in the topology shown?wireless access pointrouterhub**switch13Refer to the exhibit. How many subnets are required to support the network that is shown? 2**34514What does the term “attenuation” mean in data communication?**loss of signal strength as distance increasestime for a signal to reach its destinationleakage of signals from one cable pair to anotherstrengthening of a signal by a networking device15To establish a console connection from a computer to a Cisco router, which cable wiring option would be used?**crossover cablestraight through cablerollover cableV.35 cable**greater distances per cable runlower installation cost*limited susceptibility to EMI/RFIdurable connections*greater bandwidth potentialeasily terminated17Refer to the exhibit. A network technician has been allocated the 192.168.1.0/24 private IP address range for use in the network that shown in the exhibit. Which subnet mask would be used to meet the host requirements for segment A of this internetwork?**255.255.255.128255.255.255.192255.255.255.224255.255.255.240255.255.255.248Which subnet mask would be assigned to the network address of 192.168.32.0 to provide 254 useable host addresses per subnetwork?255.255.0.0**255.255.255.0255.255.254.0255.255.248.0cross-overstraight-through**rolloverpatch cable20Which option identifies the primary interface which would be used for initial configuration of a Cisco router?AUX interfaceEthernet interfaceserial interface**console interface21What are two common methods for setting a UTP Ethernet port to MDI or MDIX operation? (Choose two.)cable color code associationcable selection and configurationuse of cable testers to determine pinoutsthe automatic detection and negotiating of MDI/MDIX operation of the portthe enabling of the mechanism to electrically swap the transmit and receive pairs**the enabling of the mechanism to electrically swap the transmit and receive pairs**the automatic detection and negotiating of MDI/MDIX operation of the port22Which device is used to create or divide broadcast domains?hubswitchbridge**routerrepeater23Refer to the exhibit. Assume that all devices are using default settings. How many subnets are required to address the topology that is shown?134**57。
项目10习题参考答案
项目10 课后习题参考答案简答题1：常见的IPconfig命令有：ipconfig/all 命令、ipconfig/release 命令、ipconfig/renew、ipconfig/displaydns命令、ipconfig/flushdns 命令。
2、ping 是潜水艇人员的专用术语，表示回应的声呐脉冲，而在计算机网络中中ping 是一个十分好用的TCP/IP 工具，它的主要功能是检测网络的连通情况和分析网络速度。
3、1、网络故障排除；2、网络性能优化；3、网络安全检测；4、网络规划和设计4、Route命令可以在数据包没有有效传递的情况下，利用route命令查看路由表；如果traceroute命令揭示出一条异常或低效的传输路径，则可以用route命令来确认为何选择该路径，而且可以配置一个更有效的路由。
5、telnet优点：1、远程登录客户端用途广泛由于Telnet 连接实际上是标准的TCP 连接，因此可以使用客户端来使用或测试依赖TCP 作为传输协议的其他服务。
例如，通过一个简单的请求，您可以检查HTTP服务器的功能或（如前所述）电子邮件服务器的状态。
2、可以跨平台使用连接协议可以跨平台使用这一事实增强了这种多功能性。
只有少数设备不支持官方IETF 标准。
客户端和服务器计算机是否依赖于相同的操作系统也无关紧要。
3、无限制地访问目标资源Telnet 的另一个优点是，如果已授予权限，它允许不受限制地访问受控系统的资源。
telnet缺点：1、未加密的数据交换使用Telnet 协议时，连接设置和数据传输均未加密。
没有口令保护，远程用户的登陆传送的帐号和密码都是明文，使用普通的sniffer都可以被截获；没有强力认证过程。
只是验证连接者的帐户和密码。
2、完全访问权限使黑客更容易用户发送的所有信息都可能被第三方以纯文本形式拦截，包括远程访问所需的登录信息。
这意味着黑客接管系统不会有太大麻烦。
3、只有少数服务器可以通过Telnet 访问因为telnet具有一定的安全隐患，所以许多服务器都会选择禁用Telnet服务。
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参加考试- ERouting Chapter 10 - CCNA Exploration: 路由协议和概念(版本
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1链路状态数据包何时发给邻居？
每30 秒
每180 秒
抑制计时器超时之后
链路进入运行状态或断开时
发生路由环路时
2为了构建准确的SPF 树，区域内所有链路状态路由器上的哪个数据库或表必须相同？
路由表
邻接表
链路状态数据库
邻居表
拓扑数据库
3为什么使用链路状态路由的网络中很少发生路由环路？
每台路由器都根据跳数建立起对网络的直观印象。
路由器在网络中发送大量LSA 以检测路由环路。
每台路由器都建立起对网络的完整而且同步的印象。
路由器使用抑制计时器来防止路由环路。
4在使用链路状态路由的网络中，什么可以加速收敛过程？
由网络变更触发的更新
按固定间隔发送的更新
仅发送给直连邻居的更新
包含完整路由表的更新
5
请参见图示。
如果使用链路状态路由协议，以下哪项陈述正确描述了从10.0.0.0/24 网络到192.168.1.0/24 网络的流量所使用的路径？
BOS -> ATL，因为该路径的跳数最少
BOS -> ATL，因为该路径的开销最高
BOS -> ORL -> JAX -> ATL，因为该路径开销最低
流量将在所有链路间实施负载均衡
6与距离矢量路由协议相比，链路状态路由协议有哪两项优势？（选择两项。
）
由于有了拓扑数据库，不再依赖于路由表。
每台路由器独立确定到每个网络的路由。
链路状态协议对路由器处理器能力的要求比距离矢量协议更低。
在初始LSP 泛洪后，传播拓扑结构的变更时占用更小带宽。
通过频繁发送定期更新，拓扑数据库中不正确路由数目降至最低。
请参见图示。
在从路由器JAX 发送到路由器ATL 的LSP 中，可以看到哪种类型的信息？
跳数
路由的正常运行时间
链路的开销
正在使用的所有路由协议的列表
8以下哪两种路由协议使用Dijkstra 的最短路径优先算法？（选择两项。
）
RIPv1
RIPv2
IS-IS
EIGRP
OSPF
请参见图示。
当使用链路状态路由协议的路由器 D 添加到网络中后，在它了解网络拓扑结构其所做的第一件事是什么？
它向路由器 B 和 C 发送LSP 数据包。
它向网络中的所有路由器发送LSP 数据包。
它向网络中的所有路由器发送Hello 数据包。
它向路由器 A 和 E 发送有关其直连邻居的信息。
它向网络中的所有路由器发送有关其直连邻居的信息。
当其接口处于up 状态时，它便能获知自己的直连网络。
10
请参见图示。
JAX 会如何处理来自ORL 的链路状态数据包？
向 ORL 和 BOS 路由器发送其更新后的路由表
将单独的链路状态数据包从连接到 BOS 的接口发送出去
查询 BOS 以了解是否有更佳的路由
只将其添加到本地路由表中，不执行任何其它操作
11 哪两种事件将会导致链路状态路由器向所有邻居发送 LSP ？（选择两项。
）
30 秒计时器超时
网络拓扑结构发生变化时
运行贝尔曼-福特算法之后立即发送
DUAL FSM 建立拓扑数据库之后立即发送
路由器或路由协议初次启动时
12
新任网络管理员的任务是为某软件开发公司选择合适的动态路由协议。
该公司拥有超过 10器，使用 CIDR 和 VLSM ，要求快速收敛，并能同时使用 Cisco 和非 Cisco 设备。
该公哪种路由协议？
RIP 第 2 版
IGRP
EIGRP
OSPF
BGP
13 为使网络达到收敛，每台链路状态路由器会执行哪三个步骤？（选择三项。
）
使用自动总结缩小路由表大小
构建一个链路状态数据包 (LSP)，其中包含每条直连链路的状态
向所有邻居发送 LSP ，邻居随后把接收到的所有 LSP 存储到数据库中
按一定时间间隔发送 Hello 数据包来发现邻居并建立相邻关系
构建完整的拓扑图并计算到达每个目的网络的最佳路径
使用 DUAL FSM 选择有效且无环路的路径，并将路由插入到路由表中
14
哪两项陈述正确描述了链路状态路由过程？（选择两项。
）
区域中的所有路由器都有链路状态数据库
区域中的每个路由器都将向所有邻居发送 LSP
LSP 使用保留的组播地址 224.0.0.10 来访问邻居
通过运行扩散更新算法 (DUAL) 来防止路由环路
可靠传输协议 (RTP) 是用于发送和接收 LSP 的协议
15 链路状态路由协议运行什么算法来计算到达目的网络的最短路径？
DUAL
Dijkstra
贝尔曼-福特
Diffie-Hellman
16 现代链路状态协议通过哪些功能来尽可能降低处理器和内存要求？
将路由拓扑结构分割成更小的区域
为路由计算分配较低的处理优先级
使用更新计时器限制路由更新
严格执行水平分割规则以减少路由表条目
17链路状态路由过程的最后一步是什么？
将后继路由加入路由表中
SPF 计算到达每个目的网络的最佳路径
向所有邻居发送LSP 以收敛网络
运行DUAL 算法以找出到达目的网络的最佳路径
18链路状态路由器在接收到来自邻居路由器的LSP 后会立即执行什么操作？
向邻居发送LSP
计算SPF 算法
运行贝尔曼-福特算法
计算到达目的网络的最佳路径
19
请参见图示。
如果所有路由器和接口都配置为使用链路状态路由协议，则路由器 D 将从哪到hello 数据包？
A 和E
B 和C
A、B、C 和E
仅 C。