考试波澜不惊，实验题老三样，选择和拖图也没见到什么新题。但是碰到不少自己在学习题库时疑惑的争议题。根据考分结果，感觉大部分自己的判断是正确的。因此，贡献我自己整理的题库勘误，大家可以发表意见。总之，不能死记题库，还是要深入学习。6 O) g1 S ^* G' F" C! w
QUESTION 20 Which two statementsabout CDP are true? (Choose two) A. It can bedisabled only at the interface level. B. Devices withCisco Discovery Protocol configured send advertisement messages to a multicast address on aperiodic basis C. It is disabledwhen switches have mismatched native VLANs. D. Devices withCisco Discovery Protocol configured send advertisement messages to a broadcast address on aperiodic basis. E. VTP relies onCisco Discovery Protocol to carry VTP domain information CorrectAnswer: BC9 P6 W: \* N% I2 A" ~( N7 Q/ ^$ H
I think:BE
8 n j: r: r! ]+ X) }9 m0 R! [Native vlan不匹配就是靠cdp通告的。E本身是正确的8 [% D+ u, |& m X+ ?0 z6 m
' b! o$ P/ v& O$ @' X1 ?! `/ \, Q* V9 ?QUESTION 38 You have recentlydeployed an access switch with two fiber cables that connect it to adistribution switch in EtherChannel mode.Soon after it booted up, one of the uplink ports to the distribution switch waserrordisabled. Which option is themost likely reason for the problem? A. The port-channeldetected an inconsistent configuration B. The switch isoperating in UDLD aggressive mode and it failed to receive a UDLD message fromthe peer C. spanning treedetected a loop D. The switch isoperating in UDLD normal mode and it failed to receive a UDLD message from thepeer CorrectAnswer: A
! w+ \: R0 k) sI think：B# a# M/ }6 D+ [9 j2 l; }
Portchannel misconfig会down掉channel中所有的物理端口以及channel端口本身。Udld只down掉单通的那个端口, U) Q9 Y3 c6 {6 _/ [4 Y a
2 a+ O) U$ f$ U9 aQUESTION 55 Which twocircumstances can cause a port to errdisable? (Choose two.) A. It is connectedto a host with an NIC that is unable to recognize B. The switchincurred a port security violation. C. It detected acollision. D. It learned a newMAC address. E. It detected apeer with a matching duplex. CorrectAnswer: BE' I, U6 U, k$ p4 k# s$ c9 ~& K: G! k
I think:BC（除非E的正确写法是It detected a peer with a mismatching duplex）( ?' P( O7 U& v
Errdisable的原因：0 M) H- N2 x! V5 i- {6 D% i
Duplex mismatch/ q2 I1 X7 ]6 M6 x% ], w9 w, M) l
Portchannel misconfig, Y$ Q) x$ X& c5 `
BPDUguard
/ d% T( e6 l3 n, N: @% qUDLD+ [1 [7 A7 z1 j/ D% R
Late-collision% X# |! B9 l" {
Security( [, z2 I0 _- z( ~1 p2 J
PAgp Flap6 w4 N+ |2 ~7 N: J8 `2 U
L2TP guard
: @; m* h$ v, ?7 W+ rDHCP snooping rate-limit
' ^9 f8 E1 h/ h* bGBIC-SFP misconfig/ E( y# \8 F8 ]- ?- @( B# }
ARP inspection" z# f5 \8 H) ^' i
Inline Power
9 e& Y+ e: J' j' G8 h ) z5 C3 L6 V1 H) r2 ]/ u
QUESTION 82 For which reasonwould you configure RSPAN instead of SPAN on your network? A. RSPAN providesmore complete monitoring of the traffic on a single switch. B. Only RSPANdevices can monitor traffic on other device C. Only RSPAN canlog traffic on a VLAN that spans multiple switches. D. Only RSPANsupports STP on multiple switches across a campus. CorrectAnswer: C1 w$ i. c3 ^' `! E- e
I Think: B
4 m" p! H/ ]& i8 P# a! S5 iC写得是log，即记录日志，而不是监控流量
1 D7 Y3 h; S* `2 z" N D ! B) W4 T; u$ j1 |6 Q
QUESTION 126 Which two newfeature are included in VTP3?(choose two) A. VTPs can now beconfigured in off mode B. VLANs configuredfor token ring are now eligible to participate in VTP C. VTP now supportMD5 passwords D. it can beconfigured to prevent the override of the vlan database CorrectAnswer: AC
+ M9 E8 x* K$ h7 n0 Y3 W: zI Think:CD, R( V: m. z n# R7 j+ B2 \
VTP 1-3都有off mode) S4 d! K6 _5 S# r f' |' {" f6 i$ S& W
VTP 3引入了primary server模式，作为最权威的vtp服务器，其他server不能更改% m6 C4 b$ m( P3 u- ]
2 d, V" o* P- G# ?- \: R1 N
QUESTION 127 Refer to the exhibit.A single server in Company 123 is connected via EtherChannel to a singleupstream switch. Which EtherChannel load balancing method on the switch makesoptimal use of the redundant links as traffic flows from the routers to theserver? A. source MACaddress B. source IP address C. source anddestination MAC address D. destination MACaddress CorrectAnswer: A2 C- X- ?0 @ _* @1 s' A4 R5 |
I Think: B
1 q$ V2 v) u" a; u2 U* i$ I/ d没有标注两个路由器以太口的MAC地址，不知道最后一位分别是0和1，所以用mac地址效果不明，最好用source ip8 V0 G g! L/ c& U+ K
% W) W+ E! E. U9 g; nQUESTION 144 Refer to the exhibit Which two statementsabout the network environment are true? (Choose two.) A. Interface fa0/1and fa0/2 cannot communicate via Layer 2 switching. B. Interface fa0/1and fa0/3 cannot communicate via Layer 2 switching. C. Interface fa0/2and fa0/3 can communicate via Layer 2 switching. D. The twoaaaa.aaaa.aaaa MAC address entries must be from the same VLANs. E. The twoaaaa.aaaa.aaaa MAC address entries must be from different VLANs. CorrectAnswer: AE$ q$ @3 S$ j; J$ R- P u( {
答案没问题，题目抄错了，vlan号从上到下分别是：10 10 20
' H9 H( N' r/ K+ n0 R 0 A& c/ M2 v' H- U. c) ^
QUESTION 160 which commandenables you to determine whether any interface on a device was shut down as aresult of a port security violation? A. showport-security address B. show errdisabledetect C. show interfaceerr-disabled status D. showport-security CorrectAnswer: B/ W5 H. z0 \; m, M& G* h$ B
I Think: D5 L- B6 b \% g; e6 t- U9 [ I7 M
B是看哪些errdisable的探测是enable的，只有D才能看到由于port-security被关闭的端口
# X, Q: e- G# u' k
$ d; d0 F" m- o% U2 d4 @6 GQUESTION 183 Which two statementsabout source port monitoring in a SPAN are true? (Choose two.) A. Traffic through adestination port can be copied and included in the SPAN session. B. The entireEtherChannel must be monitored. C. It can monitoronly FastEthernet and GigabitEthernet port types. D. It can monitorindividual interfaces within a port channel. E. It can monitoringress and egress traffic. CorrectAnswer: AE- \8 u3 P4 S |7 V3 x# R
I Think: DE4 U+ e5 m# s: O# h. W
A显然错误，span是可以监控channel的物理端口或整个逻辑端口的0 R) R5 z9 `3 P w
: [: u# l" r/ \/ I
QUESTION 185 Which two commandsdisplay the VLANs that are present in the VLAN database? (Choose two.) A. showrunning-config B. show vlandatabase C. show vlan brief D. show vlan E. show vlan id CorrectAnswer: AD G# K3 n# z* `
I Think: CD( |; H. w d5 ~' Q3 S8 J' d
敲一下命令看输出就知道了 A最大的问题在于如果是通过vtp学习到的vlan是看不到的( F' S1 o! x$ w9 z
Z' H" u1 d+ U* X. \0 a
QUESTION 203 Which two commandsenable you to determine the native VLAN that is configured on an interface? (Choose two.) A. show interfacestatus B. show interfaces C. show interfacetrunk D. showrunning-config E. show interfacebrief CorrectAnswer: CE
, T5 c' ?, Q2 [% }5 \* ?I Think:CD+ A$ c3 z9 E) D9 B5 p& Z- r
没有E这个命令
# k" X( e3 b. g; E
' O6 v9 ?7 U* D% J- q- r2 UQUESTION 276 Which two statementsabout manually-configured LACP EtherChannels are true? (Choose two.) A. LACP negotiationmust be disabled on both devices in the EtherChannel B. They requireCisco Discovery Protocol. C. Each physicalport in the EtherChannel must have the same speed and duplex settings. D. LACP negotiationmust be disabled on one device in the EtherChannel. E. They use an MD5hash for equal load balancing. F. If the physicalport configurations on the two devices are different, the ports are placed intothe errdisabled state CorrectAnswer: AC7 I' ?9 s# V; K0 v/ @
I Think: CF
: Y C/ Y% C$ d$ i0 x! t协商是否关闭并不影响不选A，由于Portchannel-misconfig默认打开，所以F表述正确
4 m& q; |$ m/ ~( g
. ?$ w: s( G$ hQUESTION 277 Which four LACPcomponents are used to determine which hot-standby links become active after aninterface failure within an EtherChannel bundle? (Choose two) A. interface bandwidth B. system ID C. interface MACaddress D. hot-standby linkidentification number E. port number CorrectAnswer: BE3 p1 Q$ r* u" c# r$ }9 T& p; T. o
原题是要选4个答案（which four lacp components）还有两个选项是：+ f6 b. Z2 @! ^ I, r" D; t t0 Z, ^2 W
LACP system priority9 U: p3 w: V6 q. B
LACP port priority
+ o6 \: E4 L* Y/ A8 z
- R. l5 W8 q1 o9 e0 R. _) S& vQUESTION 307 An access switch hasbeen configured with an EtherChannel port. After configuring SPAN to monitorthis port, the network administrator notices that not all traffic is beingreplicated to the management server. What is a cause forthis issue? A. VLAN filters arerequired to ensure traffic mirrors effectively. B. SPANencapsulation replication must be enabled to capture EtherChannel destinationtraffic. C. The port channelcan be used as a SPAN source, but not a destination. D. RSPAN must beused to capture EtherChannel bidirectional traffic. CorrectAnswer: C
9 A* i9 }* Q5 n/ r/ jI Think: B
6 M( J, S' c! Q6 L7 v& zC表述正确，但是答非所问5 q; ~7 T; P4 G7 D% o* S/ z
Span默认不镜像vtp、stp、trunkprotocl等流量，如果要完整镜像就要加入replica关键字9 {% f) J2 P2 u6 j" R8 f# ]) K
3 a; ^* j: B4 W; P$ H1 d) c6 [$ g
QUESTION 309 which two statementsabout dynamic MAC address learning are true?(choose two) A.Dynamically-learned MAC addresses can be cleared on a per-interface basis only B. it must beenabled on ports with port security enabled C. switch interfaceslearn MAC addresses dynamically by default D. it can bedisabled on a per-vlan basis only E.Dynamiccally-learned MAC addresses supersede static MAC addresses CorrectAnswer: AC
4 d9 {0 F/ \5 t# J8 U+ T( EI Think:BC
( { |6 Z% j2 H5 }5 Q5 u动态mac可以在global模式、vlan模式、端口模式清理，A错. x. _) P" d6 P/ s6 w0 S- V; c+ T
打开了port security的端口必须强制打开mac learning B正确- ~$ ~/ p* J0 P! v4 Y8 V- j$ B
9 ]1 j2 P c$ K' }* t2 C* ZQUESTION 314 Which commandremoves all Mac-address from port channel ？ A. Clear mac-addresstable dynamic B. Clear mac-addresstable dynamic addresses mac addresses C. Clear mac-addresstable dynamic interface interface-id D. gyros for all E. Clearmac-addredss table dynamic vlan vlan-id CorrectAnswer: A4 t6 I \* X2 W4 D$ Q6 p! r( q7 `
I Think: C
* o4 f( J) g1 D+ o8 P3 fA会清理掉整个mac表
; e4 W" w' a) H) E. XClear mac-address tabledynamic interface port-channel 1正解0 i O" E, Z; G& l( W
5 E% h' P2 Q6 Z3 o( }- l9 `) m& f
QUESTION3201 g9 T% M* l& Y) N0 S- k
Source Port：2 l$ y# S2 ?5 i( }0 c1 m1 {
It can bean Etherchannel Port
6 u; U1 z4 f9 a0 wIt is themonitored Port3 I0 Q1 ?$ j2 N& _2 Y* R, g+ H T
Multipleports can be included in a single session! a+ X. [( M0 t& ^
DestinationPort:$ j! c4 f! I) y. ~7 v
It isexcluded from STP% @2 D3 u6 ^3 k0 t( G' d
It isremoved from portchannel
. V1 E0 W b: \+ ^$ m0 `0 BIt can beany physical Ethernet Port7 [9 B: Z% g+ C' S# U% Z
3 ]% K( `" h# C3 R% uQUESTION3218 u a+ J. c1 l9 J: K" b! L
True ofRSPAN VLAN y Z4 ~% l3 \/ o
MAC addresslearning is not support- M7 W. e H% A3 b: l- _' z
They canonly be configured on trunk port4 m. `: X/ ~- J, I2 T5 J, v
They canbe configured with STP only on the source port
7 g9 z" W3 h* N+ Z- nThey use VLAN ID from 2 to 10011 q% t$ S |, p$ i
' A# J! f# r) c& nFalse of RSPAN VLAN- ~4 m: i8 h6 _! }
They are not supported with vtp
& f: G; t' D' K; T4 Z( W; d7 C" qThey can be configured only on access port
, A( x# Q- [& ]' y! B4 r& ZThey use VLAN ID from 2 through 1024. m X; D0 i, v- u
. J/ L+ w" z% Z' v
0 U) s# D L9 T2 q) D) |+ p! _, t+ H | 
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发表于 2019-11-21 21:19:54
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