面試題目09年9.8日7解法

1、CCIEerview(2009 )1.給了好幾個(gè) ip dhcp pool，里面的 network 內(nèi)容是一樣的。有的 POOL 里沒有 DNS，有的 POOL 里沒有 default-gateway，問用戶為什么能得 IP，但上不了網(wǎng)，對于獲得 no nds pool 的地址的，沒有 dns，不能對于獲得沒有 default-gateway 的，沒有 gateway，不能非直連網(wǎng)段（lins）1.VTP 哪種模式下，PRUNE 是不生效的；Transparent2.sh run 里有明碼，如何解決？service password-encryption3.RSVP 用到了哪種隊(duì)列機(jī)制；WFQ

2、 /llq/cbwfq/ip rtp priority4.EIGRP 的四種 METRIC 類型Bandwidth Delay Reliability Load（MTU 未用）metric = 256 * k1*BWIGRP(min) + (k2* BWIGRP(min)/(256-LOAD) + k3*DLYIGRP(sum) x k5/(RELIABILITY + k4),5.多播地址范圍是多少 -556.dscpDifferentiated ServiCode Po。 DSCP replaIP precedencehe ToS field ofthe IP header the ToS

3、field with the DS field where the six high-order bits are used for theDiffServ Code Po(DSCP)7.4 臺 IBGP 需要的 neighbor 命令/*這題請參考 9.10回憶if full mesh ,it is 8(4*neighbor remote-as 4*neighbor update-source ).if route reflector, reflcetor is 12(4*neighbor remote-as 4*neighbor update-source 4*neighbor route

4、-reflector-c nt) or 11(4*neighbor remote-as 4*neighbor update-source 3*neighbor route-reflector-c nt)8.SSH 需要配哪些東西crypto key generate rsa配置 ip-name1配置 hostnameR1(config)#line vty 0X/*在 line 下R1(config-line)#transport input sshR1(config-line)#login localUsernamepasswordyyyOr aaa new-mAaa authenticati

5、on login ssh-login local Line vty 0 XLogin authentication ssh-loginTransport input ssh / 默認(rèn)就 enable9.show ehterchannel summary 正常接口后面都有個(gè)(P)，有一個(gè)沒有的，問為什么 另外的一個(gè)端口沒有進(jìn)入 channel-group.可能另一個(gè)鄰居端口加在其它組中；down/ 未啟用 、非動(dòng)態(tài)協(xié)商等等10. 在一個(gè) subnetting network 中，cisco 提供了一個(gè) feature 可以讓每個(gè) subnet 都能多一個(gè)可以使用的網(wǎng)絡(luò)Ip subnet-zero

6、11. 問在部署 qos 中要用的 3 個(gè)功能是什么？/或答分類打標(biāo)記、queue 和 ra12. ripv2 使用什么決定路徑imitingRIPV2 rip use the hop as its metric.when the route throurouter it will add one13. ospf 的默認(rèn)路由 metric 如何計(jì)算ospf one口帶寬dred million bit per sec divide by the bandwith of theerface/* 100M/ 接14. 在 abr ,什么樣的 lsa 會(huì)被 blocked ,不進(jìn)入到 stub ar

7、eaLSA4 and LSA515. 兩個(gè)路由器，直連，建立 EBGP，使用了一條 nei 命令，問你為啥不通在每臺路由器上只有一條 nei 命令的話，連接建立不起來，可能是沒加 update-source 和TTL 多跳。或者 ip 地址不對；16.2R1-R4-R3，因?yàn)?R2 收的 MED 值比較小。17. 他說跑 SPT 問是 SPARSE 還是 DENSE MODES 是源 R 是 接收無 RP，dense mode有 RP，發(fā)生了 switchover，sparse mode18. OSPF show ipf nei 輸出的對不（考生回答說：是對的問 WHY 了）DRother 是

8、 2way，DR 和 BDR 是 full，p2p 線路是 full19. 看圖題如圖，問：該表是通過什么命令得到的。3Show ip pim nei(有可能考官還會(huì)問怎么拼寫 PIM) Protocol-Independent Multicast20. 如圖：R1 上有個(gè) 6 接口，做了 redistribute connect 動(dòng)作R3 上作了 RIP redistribute要求。Describe the routes/LSAo OSPF 的動(dòng)作。he area 0 and area 1Area 0Area 11,2,3,51,2,3,721. 四路由器，下面兩個(gè)接了交換機(jī)，交換機(jī)接 p

9、c，問 IGMP SNOO交換機(jī)上配置 ip igmp snoo在哪做22. 關(guān)于的描述不對的一項(xiàng)，我選的降低利用率IPv4 and IPv623. ip 包哪些字段定義一個(gè) flow源/目的 IP，Protocol ID，ToS24. IPV4 包.給的圖中有兩處是空白的,問你少了哪兩點(diǎn)？源地址 and 目地地址，少 tos 和 total length425. What field in IP packet is prevented the packet from a route to router forever?TTL26. 解釋水平分割矢量路由協(xié)議水平分割：從一個(gè)接口收到的路由不會(huì)從

10、原接口送出去。BGP:從 iBGP 學(xué)來的路由不能送給另一個(gè) iBGP 鄰居。OSPF:通過 ABR 從一個(gè)區(qū)域?qū)W來的路由不會(huì)通過另一個(gè) ABR 送回原區(qū)域。目的：防環(huán)27.as ？AS IS Autonomous systemEigrp 的 as ，ProssBGP 的 as,These systems are routings，a set of routers running one or moreIGPs under a common administration.28. arp 和 rarp 是單播，組播還是廣播包 ？請求包是廣播，響應(yīng)包是單播；29.R3R4R3 配置：no ip c

11、lasslessip route 5能不能上ernet？有類路由查找，如無目標(biāo)網(wǎng)絡(luò)的主網(wǎng)，按默認(rèn)路由發(fā)送；丟掉。目標(biāo)主網(wǎng)，但無相應(yīng)子網(wǎng)，則30. 根據(jù)給定情景選擇一個(gè) acl，相當(dāng)于問 acs-list 1 permit yy.yy.0.0 55 和acs-list 100 permit yy.yy.0.0 55 區(qū)別任何路由都由 2 部分組成：前綴及前綴長度acacs-list 1 僅匹配路由前綴，無法匹配前綴長度。s-list 100 不僅匹配路由前綴，而且能匹配前綴長度；31.描述了 4 句話，問是什么：第一個(gè)是說對進(jìn)來的數(shù)據(jù)包有用第二個(gè)是和他匹配的數(shù)據(jù)包 FORWARD第三個(gè)是和他不匹

12、配的數(shù)據(jù)包 drop第四個(gè)是可以和控制列表配合使用uRPF32. 在下列情況，ICMP 發(fā)送那種類型的包要么是 echo 和 echo reply1)echo 和 echo-replyecho 消息使用命令產(chǎn)生 icmp type：8，用來測試連通性。Echo-reply 用來回復(fù)echo 消息，ICMP type：0。Router Advertisement和 Router SelectionIRDP協(xié)議（ICMP 路由器發(fā)現(xiàn)協(xié)議） 使用這兩種ICMP消息，Router Advertisement為type9， Router Selection為type10，IRDP使主機(jī)能夠發(fā)現(xiàn)本地網(wǎng)絡(luò)中

13、的路由器，并使用路由器的ip地址作為網(wǎng)關(guān)地址。Redirect2)3)Redirect 消息使用 type5，作用為：通知多路網(wǎng)關(guān)更好的路由器作為下一跳。Network Unreachable網(wǎng)絡(luò)中主機(jī)去往目的地址比使用默認(rèn)4)Network Unreachable 類型為 type3，有幾種常見 code： 0:Network Unreachable 路由器路由表沒有去往目的地址的路由條目1:Host Unreachable 數(shù)據(jù)已經(jīng)發(fā)往最后一跳路由器，但 arp 查詢不到目的主及的 mac2:Protocoreachable 數(shù)據(jù)包到達(dá)目的主機(jī)，但主機(jī)沒有運(yùn)行相應(yīng)的上層協(xié)議3:Port U

14、nreachable 數(shù)據(jù)包到達(dá)目的主機(jī)，但主機(jī)端口沒有被4:Fragmenion Needed and Dont Fragment Flag Set 數(shù)據(jù)包超過 mtu 值但設(shè)置了不能分片。Time Exceeded ICMP MessageTime Exceeded 使用 icmp type 11。作用是通知主機(jī)發(fā)送數(shù)據(jù)包的數(shù)據(jù)包由于超時(shí)（ttl=0）被丟棄。5)633. 根據(jù) 3 個(gè)說明說出這個(gè)是描述 ipv6 里面一個(gè)什么概念？注意 3 個(gè)描述，如果描述是：代替 arp，無狀態(tài)自動(dòng)配置，路由重定向，那描述的協(xié)議就是 IPv6 NDP34. IPv6 的 solicited-node m

15、ulticast address 的作用是什么？作用 1：代替 IPv4 網(wǎng)絡(luò)中的 arp (replacement of arp )作用 2：地址Tip:檢測(DAD)Replacement of arp : 由于 IPv6 不使用 arp，因此使用 solicited-node 組播地址，用于節(jié)點(diǎn)或路由器學(xué)習(xí)本地鏈鄰居的鏈路層地址。DAD: 在 IPv6 無狀態(tài)自動(dòng)配址之前，使用 solicited-node 組播地址來探測本地鏈其他 ipv6 設(shè)備的地址和自動(dòng)配址有無。RIP andEIGRP35. 跑 rip 問 R1 到 R2 幾跳 ？72 跳Note：r1 到 R2 不論怎么考慮，

16、都要至少跨過中間的三層交換機(jī)，走兩步到 r2；36. 一個(gè)路由表，有 3 條，分別從 ri擇哪調(diào)走先最長匹配，在看 ad，最后看 metricpf，eigrp 學(xué)過來的，到達(dá)相同目的，問路由選/it will select the entry with the longest prefix , then it will select the entry/ which is learned from the route protocol with the lowest AD,37. Rip v1 不連續(xù)子網(wǎng)，有圖，具體不清楚（但肯定是不連續(xù)子網(wǎng)），問解決方法【1】加輔助地址將主網(wǎng)連續(xù)【2】改成

17、v2，且關(guān)閉 auto-summary【3】NAT【4】換成其它無類路由協(xié)議。38. EIGRP 非等價(jià)負(fù)載問題 ，如圖示：Question:if we set the variance 2,how will router A choose the path to 172 network?if the variance is 2, eigrp will choose B and C as its best path to get to 172,Note：because the router cs advertised distance to a destination meets the FC

18、,and the FD is 20, Bs AD Local_pref -as-path -med75.Local_preference 的作用范圍（題目意思大概是這樣的）My A：Local_preference is a well-known discretionary attributet is used only insidea AS; it is not passed outside of a AS Note：卷二上解釋： LOCAL_PREF is short for local preference. This well-knowndiscretionary attribute

19、is used only in updates betpassed to other autonomous systems.nernal BGP peers; it is not76. Weight 的作用范圍My A：weight is a Cisco-specific BGP attribute not advertise to any otheerNote：t app s only to a single Router and卷二上解釋：weight is a Cisco-specific BGP parameter within an individual router. It is

20、not communicated to other routerst app s only to routes77.No advertise the routed but router C can received it, how resolve it ?/ 題意可能是說 A 通告一條帶有 no-advertise community 的路由給 B ，問 C 能否收到 ？如何解決 ？19Not advertise to any BGP peers, you can set the no-export or local-as to solve itcase.hisMulticastrouting

21、78. 在一個(gè)運(yùn)行 sparse-dense-mode 的組播網(wǎng)絡(luò)里，當(dāng) rp down 掉時(shí)，他的源和接受者會(huì)responses？當(dāng) RPdown 了，如果在源和接收者之間已經(jīng)有一棵 SPT 樹，且該樹不經(jīng)過 RP，多播流不受影響；如果 TREE 還沒建立，1 靜態(tài)配置 RP 的情況 2 動(dòng)態(tài) RP 情況下 RP 和組的關(guān)系尚未過期時(shí)，源和接收者間因?yàn)?RP 不存在，所以不會(huì)有多播樹建立起來，不會(huì)有多播流流下來；而動(dòng)態(tài)配置 rp 的情況下，當(dāng)多播路由器上 RP 和組的dense mode 工作。關(guān)系過期之后，多播轉(zhuǎn)發(fā)切換到79. 第二題:給個(gè)圖.是跑組播的.然后問你用的是什么上面 4 個(gè)路由

22、器每 2 之間有藍(lán)色箭頭，下面是一個(gè)交換機(jī)連多臺路由器。之間是紅色箭頭，20問之間分別跑什么協(xié)議（注意是協(xié)議）如果上面是 4 臺路由器，下面是交換機(jī)和 PC 機(jī)的話，路由器間是 PIM，路由器/交換機(jī)和PC 間之間是 IGMP80. what is RPF?Answer: the routing table for unicast is checked against the source address multicast datagramheIf the datagram arrived on theaddress:erfapecifiedhe routing table for the

23、sourceThF check succeedsOtherwise , thF check fails through the implemenion of check-in siono the sion multicast frameerface deciforwarding or discardedWhat is RPF?A router forwards a multicast datagram only if received on the upstream source, i.e. it follows the distribution treeerface to theRpf 檢測

24、：一個(gè)數(shù)據(jù)包從路由器的某個(gè)接口進(jìn)來時(shí)，路由器要檢測這個(gè)數(shù)據(jù)包的源地址，判斷這個(gè)數(shù)據(jù)包是不是應(yīng)該從這個(gè)接口收到。rpf 使用的是路由表和反向路徑檢測，即去往這個(gè)源地址判斷從哪個(gè)接口出去。如果接口一致，表明 rpf 檢測成功，接口不一致表明 rpf 檢測失敗。RPF 的功能：在組播環(huán)境下，RPF 檢測為了防止組播環(huán)路。在單播環(huán)境下，rpf 檢測為了防止 ip spoofing。81. 給一個(gè)組播表，問用什么命令？show ip mroute82. 組播的 sp 和 den 的區(qū)別（1）Sp need thfor Registration information for source，dense d

25、oesnt need。dense 使用推的方式建立轉(zhuǎn)發(fā)樹（flooding and pruning），使用的是源樹（最短路徑樹 spt）；sparse 使用拉的方式建立樹，在源和 RP 間是源樹，在 RP 和接收者間是共享樹 (root-path tree (RPT)Sparse 可以從共享樹切換成最短路徑樹(Switchover)，dense 只使用最短路徑樹83. frlo描述了一種組播源發(fā)現(xiàn)協(xié)議,常用于 sparse-mode，并且工作在單區(qū)域,使用ack 作為冗余Anycast RP84. ip pim spt-threshold，解釋下，Cisco 的默認(rèn)值是多少 ？這條命令是調(diào)整

26、sparse 模式下從共享樹切換成最短路徑樹的閥值，cisco 默認(rèn)是 0 kbps Note：a router should switch from thT to an SPT when the data rate is high.21This default can be changed with thed ip pim spt-threshold, in which thethreshold for switching to the SPT is specified in kilobits per second (the default represents 0 Kbps). The r

27、outer measures the arrival rate of packets once every second. If packets for either any group or a specified group arrive at a rate exceeding the threshold,the router switches85. How RPF Work （我理解的題目意思）My A: RPF allows the router to forward a multicast packet only if the packet isreceived on the ups

28、treamerface to the source. To be specific, if the router receives amulticast packet on anerface, the unicast routing table is used to check the sourceaddress of the multicast packet. If the packet arrives on theerfapecifiedheFunicast routing table for the source address, thF check succeeds; otherwis

29、e, thcheck fails and the multicast packets are silently dropped.單播中還有一個(gè) uRPF；86.ulticast network how to select DR ? and what is the order ?在 MA 類型網(wǎng)絡(luò)上，ip pim dr-priority 高的為 DR，如果優(yōu)先級一樣，看 IP address，地址高的為 DR87. 給一個(gè)組播表，問用什么命令？1)2)3)Show Showshowip ipippim neighbor pimerfacemrouteQoS88. Which picture is

30、 Traffic ShA:B: sha, why ?traffic-shapis B,22Because Traffic-shadoes not drop flow ,but buffers the flow . and transmits themlater。 it can make the flow smoothly.A shr typically delays exs traffic using a buffer, or queueing mechanism, to holdpackets and shNote：the flow when the data rate of the sou

31、rce is highern expected兩者都使用令牌機(jī)制，令牌是設(shè)置每個(gè)時(shí)間點(diǎn)(tc)能夠轉(zhuǎn)發(fā)的數(shù)據(jù)量。對于超過轉(zhuǎn)發(fā)令牌容量的數(shù)據(jù)包嚴(yán)格丟棄。整形對超過能轉(zhuǎn)發(fā)令牌容量時(shí)不會(huì)丟棄，而是放入整形隊(duì)列緩存起來，等待下一個(gè)時(shí)間點(diǎn)有令牌時(shí)再轉(zhuǎn)發(fā)。因此整形和都能起到限速的作用，但和圖示的一樣，整形比轉(zhuǎn)發(fā)數(shù)據(jù)時(shí)更加平緩。89. Which picture is? Why.will drop the flowt exceeds the specific value of the traffic rateTheiswe set.,Second is traffic shtraffic being sen

32、t,because trffihprovides a means to control the volume ofo a network in a specified period, it can let the traffimoothness.Traffic shaqueues exs packets to stay withhe desired traffic rate.Traffic policing typically drops or marks exs traffic to stay within a traffic raimit.90. PQ major disadvantage

33、 ?Starvation of lower -priority classes when highriority classes are congested介紹 GTS 的三個(gè)特性Generic Traffic ShaClassification of traffic, so policies app d to them.t different traffic classes can have different2.Metering, using a token-bucket mechanism, to distinguish betand exceeding traffic.n confor

34、ming3.Shara, using buffering, timit.ay exceeding traffic and shit to the configured92. Whats PHB?The Per-Hehavior is indicated by encoding a 6-bit value-called the DifferentiatedServiCode Po(DSCP)- o the 8-bit Differentiated Servi(DS) field of the IPpacket header. Besides defining DSCP values and th

35、eir text names, the PHB alsosuggests a simple set of Qovalues. / 加重部分是答題重點(diǎn)ionst should be taken based on the DSCP93. 就是問什么技術(shù) : 當(dāng)網(wǎng)絡(luò)發(fā)生擁塞的時(shí)候，隨即丟棄數(shù)據(jù)包?？梢愿鶕?jù)數(shù)據(jù)包的優(yōu)先級來決定丟棄的概率。可以設(shè)置權(quán)重值。WRED2394. ipp 和 dscp 位數(shù)IPP 3bits DSCP 6bits95. What fields in IP packet is used to classification by QOS ?TOS96. what is the p

36、ure of classification?A:classification is a method to differentiate the flow, aftert ,the administrator can apply specific policyto a particular class of flow, and the administrator can recognize these flow by different classification.Switching97. Layer 2 protocol , 2-secondos,and a 50-second conver

37、gence time?Because a switch is a Layer 2 device , all VLANs use Spanning Tree to build loop-freepaths betn switches.o timer is 2 seconds ,Forward delay timer: This timer is the default 15 seconds Max age timer : The default value is 20 secondsFor STP to recover from a link failure, it takes approxim

38、a y 50 seconds ; it takes 20 seconds for the BPDU to age out ,the max age; and it takes 15 seconds for the listening s e and 15 seconds for the learning s e.非直連鏈路失效，導(dǎo)致 50 妙的收斂時(shí)間。98. SW1 是根,SW2 到 SW1 COST10,SW3 到 SW1 COST3,其它默認(rèn)的為 19,問 SW4 哪個(gè)端口是 root port?(這是原題,但也有可能問你 root 是 SW4 和 SW2/SW3,如果要是沒確定根,則需

39、要 supe)24Sw1 是 root，sw4 中間的端口是 root port Sw2 是 root，sw4 左邊的端口是 root port Sw3 是 root，sw4 右邊的端口是 root portSw4 是 root，無 root port99. 說了一個(gè)現(xiàn)象 問是哪個(gè) feature我就看到了不學(xué)習(xí)不STP 然后就說 portfast 了這題題目不太明確Portfast 是會(huì)發(fā)收 BPDU,BPDU 但是 portfast 倒是不會(huì)經(jīng)過學(xué)習(xí)和 portfast. (lins)二個(gè)狀態(tài).如果說是沒有 learn listen 二個(gè)狀態(tài),那就是100.句話描述一項(xiàng)技術(shù)，問你是什么技術(shù)

40、第一個(gè)描述是在中定義第二個(gè)是和他匹配的數(shù)據(jù)包第三個(gè)是和他不匹配的數(shù)據(jù)包轉(zhuǎn)發(fā)第四個(gè)是可以取代控制列表未知，可能是101.解釋 STP 的過程和相應(yīng)的時(shí)間Disabled-Blocking-listening-Learning-Forwarding時(shí)間：o time 2sbpdu max-age 20s Listening 15sLearning 15s102.which vtp mode will not transport vlan in vtpTransparent mode?103.SRR 和 WRR 的區(qū)別?Srr（sh In shd round robin） can make a qu

41、eue work under shd or shared mode.d mode, the egress queues are guaranteedrcentage of the bandwidth, andthey are raimited tot amount.In shared mode, the queues share the bandwidmong them according to theconfigured weights. The bandwidth is guaranteed at this level but not limited to it.Wrr (weighted

42、 round robin ) wrr service the queues based on the weight assigned on each queue in round robin.104.問 fr 口物理是 up 的, line protocol down 是什么原因？Lmi-type 不一樣 或 非 fram-relay 封裝25105.Please try to describe why the frame-relay pvc was down ？Show frame-relay pvcNote：ACTIVE PVC is up and functioning normally

43、.INACTIVE PVC is not up endtoend. This may be because either there is nomap(or incorrect map) for the local DLCIhe framerelay cloud or the remoteend of the PVC is Deleted.DELETED Either the Local Managementerface (LMI) is not exchanged betnthe router and the local switch, or the switch does noswitch

44、.ve DLCI configured on the localSIC no keepalive configured on the framerelayerface of the router.26106.r1 是 hub 端，接口模式點(diǎn)對多點(diǎn)，r2 和 r3 是 spoke 端，當(dāng) r2 down 掉時(shí)，r1 端有什么反應(yīng)27The pvc bet still active.Note：n r1 and r2 will change se to inactive. And the pvc betn r1 and r3R1 側(cè)物理接口 up，鏈路層協(xié)議也是 up；show frame-rela

45、y pvc 會(huì)看到到 R2 的 pvc 狀態(tài)為 inactive；Tip:當(dāng)顯示內(nèi)容中有 inactive 時(shí)，表明對端出現(xiàn)問題，(對端接口 shut down，no keeplive)當(dāng)出現(xiàn) active 提示時(shí)，說明 frame-relay 網(wǎng)絡(luò)正常如果為 deleted，則是本端出現(xiàn)問題了，請檢查相關(guān)配置。107.配置如下 RA： s0/0/0:en framipv add 2020:yy:yy:24:2fram map ipv 2020:yy:yy:24:4 204 broRB:en framipv add 2020:yy:yy:24:4fram map ipv 2020:yy:yy:

46、24:2 402 broquestion: why canteach other？可能是 PVC 號碼寫的不正確。Link-local 地址的 frame-relay map寫與否不會(huì)影響直連網(wǎng)絡(luò)的可達(dá)性。它只會(huì)影響到路由協(xié)議的運(yùn)行。看題目仔細(xì)觀察其他配置有無錯(cuò)誤。108.fr 的 pvc 通，s0 不通，問為什么sh 出來 pvc 是好的，但是 S0 down 了28？/*回憶不全不知道問的是什么109.給出一個(gè) show ip bgp 的表項(xiàng),其中有 3 條明細(xì),一條掩碼短的,說明這個(gè)短的掩碼的路由下一跳是 .,本地產(chǎn)生的 aggregate 路由 (BGP 匯總)Other110.給出了

47、一個(gè) pat 的配置,讓說明后面的 overload 的關(guān)鍵字的意義如：ip nat inside source lister s1/1overloadoverload關(guān)鍵字： Enables the router to use one global address for many local addresses.When overloading is configured, the TCP or User Datagrrotocol (UDP) port numberof each inside host distinguishes betIP address.n the multiple

48、 conversations using the same local111.他問有沒有可能這兩個(gè)網(wǎng)段互相通信 ？可以，使用 NAT 解決 address overlap問題112.OSPF 負(fù)載均衡問題從一個(gè)地方到另外一個(gè)地方有 3 條路徑可以選擇，運(yùn)行 OSPF，其中 2 條路徑的 cost 的總合是相同的，問 OSPF 怎么選路。我回答是負(fù)載均衡。113.Q:問描述的是什么這個(gè)協(xié)議用的 TCP 179 端口29有 peer-group，有 keepalive，有 established,從這幾個(gè)關(guān)鍵字好像是描述 BGP 建立鄰居的過程It describes the pros how t

49、o establish bgp neighbor.114.1. What is theA:65535 bytesum size of an IP packet in bytes?115.What is the multicast address updates?A:t an OSPF designated router will used to send116.What is the default OSPF reference bandwidth?1000,000 bits, 100Mbps, 108117.By default, traffic matched in a class-map

50、 sement must match all entries - true or false?A:Match-all is the default118.Under what condition(s) will r1 advertised a default routeo area 0? router ospf 100router-id log-adjacency-changesnetwork 55 area 0 default-information originate metric 100A:r1 musve a default route present in its routing t

51、able119.Which LSA type is originated by the designated router only?Type-2 (Network) LSA120. An OSPF forwarding address of indicates destination should.be forwarded to the advertising router.t packets for the external121. Does filtering an inbound OSPF prefix widistribution list removet prefix fromth

52、e routing table of neighboring OSPF routers? Why or why not?No. While the route is not installedis flooded to OSPF neighbors.he local routing table, the LSA is not filtered and122.Why are Register messages needed in PIM SM?Because thehop router does not receive the joessage, its outgoingerfacelist i

53、s empty, it is nesary to use unicast to send the register message to RP, waitingfor the joessage from RP.123. List some triggerst initiate Joessages30The receivers send the report message to last hop router, the last hop router willsend the jo When thhop router.essage.receives the register message,

54、t will send joessage to thehe situation of spt switchover, when the router find the shortest path tree whichis bettern the path betn rp andhop, the router send joessage.124. What is the primary difference bet(informs)?ns and SNMP inform requestsSNMP informs are trapst include a request for confirmat

55、ion of receipt fromthe SNMP manager.125. What is the multicast address designated router?t an OSPF device uses to communicate with the126. An NSSA Area Border Router will do what before advertising a Type-7 LSA non-NSSA area?Translate it to a Type-5 LSAo a127.4. What type of OSPF area allows only LS

56、A-types 1 and 2 as well as a single type-3 default route?Totally stubby area128.5. Which OSPF area willerface FastEthernet0/0fa0/0 be assigned:ip address ipf 100 area 12Rack1R1(configr)#router ospf 100Rack1R1(config-router)#network area 21Rack1R1(config-router)#network 55 area 2Rack1R1(config-router

57、)#network 55 area 3Rack1R1(config-router)#network area 4A: Area 12/ 接口下優(yōu)于全局，全局下，精確的優(yōu)先；129.1. Which po -to-multipotechnology utilizes an IPv4 address embedded in an IPv6address (the IPv4 address is converted to hexadecimal and then concatenated to theprefix 2002:/16) to allow isolated IPv6network to

58、remote IPv6 networks?s to be connected over an IPv4A:Automatic 6to4 Tunnels/*關(guān)鍵字 2002 這個(gè)地址是給 AUTO 6TO4 用的130.2. Which OSPF feature allows a router to continue to forward packets while undergoing specific, well-known failure conditions?A:OSPF Graceful Restart31131.3. By default, OSPF floods new LSAa

59、over allerfahe same area except.A:theerfacet the LSA arrives on.132.4. What are the default OSPFbroadcast network type?o-inverval and dead- erval for the OSFPA:10 seconds for theo- erval and 40 seconds for the dead- erval.133.5. R1#r?*r=resumereload resume*ri=”show ip route” releaserenamerloginrenew

60、rshrestartWhat is true about the:They are aliases. Moreds preceded by asterisks?specifically, they are exec level aliases. Even morespecifically, r is one of the IOS Defaultd Aliases, while ri is a custom alias.134.1. Which LSA type is flooded throughout the autonomous system by an Area BorderRouter