구텐모르겐 AmeriKa

26. Which of the following is not a characteristic of fast switching?
a. Fast switching reduces a router's CPU utilization, compared to process switching
b. all packets of a flow, except for the first packet, use the information in the fast cache
c. It can be enabled with the interface command ip route-cache
d. Fast switching uses a fast cache maintained in a router's control plane
e. Teh fast cache contains information about how traffic from different data flows should be forwarded
f. Even though the fast switching is enabled, the first packet of a flow is still process switched

답은 d인데 Fast Switching은 router의 data plane을 이용한다. control plane은 l3 switching과 router에서 동시에 사용되어지는 반면 data plane은 l3 switching과 router에서 다른 목적으로 사용되어 진다. CEF는 data plane에서 Forwarding Information Base와 adjacency table테이블을 생성한다.
data plane과 control plane의 용도에 대해 정확히 알아놓는게 중요하다.

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27. Which of the following commands will display a router's crypto map IPsec security association settings?
a. show crypto map ipsec sa
b. show crypto map
c. show crypto engine connections active
d. show ipsec crypto map
e. show crypto map sa
f. show ipsec crypto map sa

답은 a이다. d,e,f와 같은 명령어는 없다.

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28. Which of the following pieces of information will the command show interface provide? (choose all that apply)
a. Layer 1 status
b. Output queue drops
c. Interface CPU utilization
d. Cable type connected to interface
e. Layer 2 status
f. Input queue drops

좀 짜증나는 문제인듯. show interface는 해당 포트의 디테일한 정보를 보여주는 명령어이므로 c와 같이 CPU정보를 보여주지는 않는다. d의 케이블타입도 나타나지 않으므로 a,b,e,f가 되겠다.

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29. Which of the following statements concerning IGMP are correct? (choose all that apply)
a. With IGMPv1, queries are sent to a specific group
b. Hosts issuing IGMPv1 requests will be correctly interpreted by IGMPv2 hosts due to backward compatibility
c. An IGMPv2 router will ignore IGMPv2 leave messages when IGMPv1 hosts are present
d. With IGMPv2, a leave message is supported
e. An IGMPv2 host will send an IGMPv1 report on an IGMPv1 router
f. An IGMPv2 router can only allow IGMPv2 hosts to execute a join request

IGMP는 세가지 버전이 있다.
IGMPv1은 60초마다 PC에 연결성을 확인하고 3분까지 기다리게 된다. 연결은 224.0.0.1로 이루어진다.
IGMPv2는 특정그룹에게 쿼리를 보내고 PC는 leave메세지를 라우터에 보낼수 있다. IGMPv2가 IGMPv1과 통신할때는 IGMPv1으로 쿼리해야 한다.
IGMPv1 router and a mixture of IGMPv1 and IGMPv2가 있는데 여기선 생략하겠다.
답은 c,d,e이다.

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30. Which of the following are byproducts of a structured maintenance plan?(choose all that apply)
a. Predictable security vulnerabilities
b. Economies of scale
c. Improved expenditure forecasts
d. Increased downtime
e. Predictable equipment obsolescence
f. Consumption of fewer resources

중요한 문제는 아닌듯하다. downtime이 관리와 관게는 없다. 답은 a,b,c,e,f이다.

21. Which of teh following options represents the correct sequence of DHCP messages after a client initially boots?
a. DHCPREQUEST, DHCPOFFER, DHCPDISCOVER, DHCPACK
b. DHCPDISCOVER, DHCPOFFER, DHCPREQUEST, DHCPACK
c. DHCPOFFER, DHCPACK, DHCPREQUEST, DHCPDISCOVER
d. DHCPDISCOVER, DHCPREQUEST, DHCPOFFER, DHCPACK
e. DHCPREQUEST, DHCPDISCOVER, DHCPOFFER, DHCPACK
f. DHCPDISCOVER, DHCPACK, DHCPREQUEST, DHCPOFFER

discover-offer-discover-ack 그냥 외우자!

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22. Which of the following statements regarding documentation would not bo considered a helpful step in the troubleshooting process?
a. Use the Cisco Auto Configuration tool
b. Use the Cisco Rollback feature
c. Automate documentation
d. Schedule documentation checks
e. Use the Cisco Configuration Archive tool
f. Require documentation prior to a ticket being closed out

Cisco Auto Configuration Tools은 네트워크 설정하는 툴로써 문제해결과는 관련이 없다.

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23. Which of the following statements are true concerning the command ip sla monitor responder type tcpconnect ipaddress 10.1.1.1 port 23? (choose all that apply)
a. The command will initiate a probe with a destination IP address of 10.1.1.1
b. The command is used on the IP SLA responder and the IP SLA source
c. The command will allow only source address 10.1.1.1 to source probes
d. The command will initiate a probe with a destination Telnet port
e. The command is used to make the router a responder
f. The command will initiate a probe with a source port of 23

IP SLA는 특정 프로그램에서의 트래픽이 어떻게 다뤄지는지를 알아보는 툴로 사용되어진다. ip sla monitor responder type tcpconnect ipaddress 10.1.1.1 port 23은 tcpconnect의 형태로 10.4.4.4호스트를 responder의 형태로 응답을 유도하는 탐사형태이다. 시스코프레서 P427 참조. 그러므로 b에서 IP SLA는 responder로만 쓰였으므로 틀리다. c에서 10.1.1.1.은 responder의 주소이다. f는 destination이 포트 23을 쓰므로 틀리다. e는 누가 소스를 말하고 누가 데스티네이션을 말하는지 모호한 표현이므로 일단 제거. 그러므로 답은 a와 d

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24. In what situation would the command ip helper-address be required? (choose the best answer)
a. Only when there is a duplicate IP address caused by a combination of static and dynamic IP address allocation
b. On each router that exists between the client and the server
c. Only when a router separates the client from the server
d. Only if the DHCP server issues a DHCPNAK to the initial request
e. Only when the client is on the same subnet as the sever
f. Only when the DHCP pool is out of IP address

ip helper-address는 해당 interface의 트래픽을 UDP브로드캐스팅된 트래픽을 destination IP로 보내주는 역할을 한다. 즉 broadcast->unicast의 역할을 하게된다. 그러므로 떨어져 있는 server와의 연결을 도와주므로 c가 답이 된다.

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25. Which of the folowing commands will restore a previously archived configuration by replacing the running configuration with the archived configuration
a. configure archive running-config
b. configure replace
c. copy archive running-config
d. copy startup-config running-config
e. copy tftp running-config
f. configure tftp running-config

show archive를 통해 어떤 파일이 백업되어 있는지 확인이 가능하고 configure replace명령어로 restore가 가능하다. 그러므로 답은 b이다.

16. Several troubleshooters are about to work on the same problem. Which of the following troubleshooting methods would be most appropriate to make the best use of the troubleshooters' time?
a. Bottom up
b. Component swapping
c. Top down
d. Shoot from the hip
e. Divide and conquer
f. Follow the traffic path

답은 e. 그닥 설명이 필요한 문제가 아니므로 생략

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17. Which of the following are not EIGRP data structures? (choose all that apply.)
a. EIGRP database table
b. EIGRP CEF table
c. EIGRP neighbor table
d. EIGRP adjacency table
e. EIGRP interface table
f. EIGRP topology table

c,e,f는 EIGRP data structure가 아니다. 그러므로 답은 a,b,d이다.

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18. Which of the following is a valid host IPv6 address? (choose all that apply)
a. ff02:a:b:c::1/64
b. 2001:aaaa:1234:456c::1/64
c. 2001:000a:1b2c::/64
d. 2fff:f:f:f::f/64
e. ff02:33ab:1:32::2/128
f. 2001:bad:2345:a:b::cef/128

호스트는 f로 시작할수 없으므로 a,e는 틀린 답이다. 그리고 c는 마지막 비트에 대한 정의가 없으므로 틀린 표현이다. 그러므로 답은 b,d,e이다.

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19. You examine the port statistics on a Cisco Catalyst switch and notice an excessive number of frames are being dropped. Which of the following are possible reasons for the drops?
a. Unknown destination MAC address
b. Bad cabling
c. MAC forwarding table is full
d. Port configured for half duplex
e. Port configured for full duplex
f. Network congestion

만약 모르는 MAC주소일때는 Vlan에서 포워딩하게 된다. duplex자체만으로는 문제가 생기지 않는다. 그러므로 답은 b, f이다.

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20. Which of the following would be considered reasonable network maintenance tasks? (choose all that apply)
a. Ensuring compliance with legal regulations and corporate policies
b. Troubleshooting problem reports
c. Planning for network expansion
d. Providing support to sales and marketing
e. Giving presentations to management
f. Monitoring and tuning network performance

네트웍 유지관리하는데 영업과 마케팅 부서를 서포팅하는게 들어갈 필요는 없고 프리젠테이션은 더더욱 필요가 없다 그러므로 a,b,c,f이다.

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Tshoot 시험 자체가 요즘 추세에 맞게 관리위주의 문제가 많이 나오는 듯하다. 새로 출제된 routing과 switching문제를 보지는 못했지만 많은 부분 ITIL이나 CISSP와 같은 administrative쪽 측면의 문제가 많이 출제되는듯 하다.

11. Which of the following commands can be used to gather information about the AS-PATH of a BGP route? (choose all that apply.)
a. show ip bgp neighbors
b. debug ip bgp updates
c. show ip route bgp
d. show ip bgp
e. show ip bgp summary
f. sh ip bgp database

show ip route bgp neighbors는 이웃라우터의 정보만 제공한다. show ip route bgp는 bgp entry와 라우팅정보만을 제공하고 BGP의 속성값에 대해서는 정보를 제공하지 않는다. sh ip bgp database란 명령어는 존재하지 않는다. 그러므로 답은 b,d,e이다.

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12. How long will a port remain in the listening state by default?
a. depends on the number of switches in the spanning tree domain
b. 50 seconds
c. 15 seconds
d. until the root directs it to start forwarding
e. 20 seconds
f. depends on the port speed

답은 c이다. blocking (20sec) - listening (15sec) - learning (15sec) - forwarding순으로 이루어진다. 위 값들은 다 디펄트 값이다.

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13. A new router is added to an existing HSRP standby group. One of the existing routers is in an active state, the other is in a standby state. Under what circumstance will the new router become the active router?
a. The new router will become active immediately because it's the newest router introduced into the group.
b. The new router can become active only when the existing active router and the existing standby router become unavaiable.
c. The new router has a lower priority value.
d. The new router will never become active unless the existing active router becomes unavaiable.
e. The new router has preempt configured and a higher priority
f. The new router has a higher priority value.

HSRP에서 preempt옵션이 있을때는 active router가 될 우선권을 가지게 된다. higher priority는 active router를 정하는 우선값이다.

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14. Which of the following is not a valid reason for a packet to be punted?
a. The TCAM has reached capacity
b. An unknown destination MAC address
c. A packet being discarded due to a security violation
d. A Telnet packet from a session being initiated with the switch
e. Routing protocols sending broadcast traffic
f. A packet belonging to a GRE tunnel

TCAM이 프로세싱을 위해 CPU에 보내는 것을 패킷이 punt되었다고 한다. (왜 punt라고 하는지 나도 잘 모르겠다. 앞이 넙적한 배를 punt선이라고 하는데 무언가를 실어나르다라는 표현으로 쓰여진거 같다.)
TCAM은 CEF의 한 방법으로 다른 방법은 adjacency가 있다. 이 문제는 외워야 할거 같다. ㅎ 너무 광범위한 질문이여서 나도 잘 모르겠다. 하지만 일반적으로 생각해서 메모리 프로세스로 가는데 unknown destination MAC address를 저장할리는 없고, discarded된 패킷을 저장할리도 없으니 답은 쉽게 나오리라 본다.

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15. Which of the following are not true OSPF LSA rules?
a. OSPF LSA type 5 triggers an LSA type 7 at an ABR between an NSSA and the backbone area.
b. OSPF LSA type 1 triggers an LSA type 3 at an ABR
c. OSPF LSA type 7 triggers an LSA type 5 at an ABR between an NSSA and the backbone area.
d. OSPF LSA type 3 triggers an LSA type 4 at an ABR
e. OSPF LSA type 5 triggers an LSA type 7 at an ASBR but only in NSSAs
f. OSPF LSA type 2 triggers an LSA type 3 at an ABR

중요하고 중요하고 중요한 문제!
type 1 lsa - 물리적으로 연결되어 있는 subnets, local area에 국한된다
type 2 lsa - 라우터간 연결, local area에 국한된다
type 3 lsa - ABR
type 4 lsa - ABR to reach to ASBR
type 5 lsa - ASBR for outside of domain
type 7 lsa - NSSA, stub은 외부와 연결할수 없는 반면 NSSA는 할 수 있다.

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질문 달아주시면 아는대로 답변해드리겠습니다.

어제에 이어 데모버전 문제를 5개 풀어보겠다.

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6. Which of the following best describes the following command: ip flow-export destination 192.168.1.50 1500?
a. It is not a valid NetFlow command
b. It is an SNMP command that exports 1500-byte packets to IP address 192.168.1.50
c. It is a NetFlow command that will export 1500-byte packets to IP address 192.168.1.50
d. It is a NetFlow command that allows IP address 192.168.1.50 to send traffic to port 1500
e. It is a NetFlow command that will specify that the NetFlow collector's IP address is 192.168.1.50 over UDP port 1500
f. It is an SNMP command that exports flows to destination address 192.168.1.50 for packets up to an MTU of 1500

IP주소 이후에 따라온 1500이란 숫자는 당연히 포트번호이므로 답은 e이다.

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7. Which of the following are valid methods of providing a router with information corcerning the location of the RP? (choose all that apply.)
a. Statically defined RP
b. Bootstrap Router
c. Auto-RP
d. RP Discovery Protocol (RDP)
e. RP Hellos
f. RP ARP (RARP)

d,e,f같은 프로토콜은 존재하지 않는다. 그러므로 답은 a,b,c이다.

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8. Which of the following are shared distribution tree characteristics? (choose all that apply.)
a. Memory requirements are higher for shared distribution tree than for source distribution tree.
b. Creates a tree from a central RP to all last-hop routers.
c. Uses a rendezvous point.
d. An optimal path is created between each source router and each last-hop router.
e. Place (S,G) entry in each router's multicast routing table.
f. Place (*,G) entry in a router's multicast routing to table.

우선 답은 b,c,f인데 shared distributin tree에서는 RP에 조인하고 싶은 라우터는 (*,G)상태를 생성하면서 RP와 last-hop router의 연결을 설정한다.

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9. Given the multicast IP address of 224.193.5.10, what wuold the corresponding multicast MAC address be?
a. 00-00-0c-05-0a
b. 00-00-0c-c1-05-0a
c. 01-00-5e-41-05-0a
d. 01-00-5e-41-05-0a
e. 00-00-0c-01-00-5e
f. 01-00-5e-c1-05-0a

답은 d.
224.193.5.10의 2진수는 1100.0001.0000.0101.0000.1010이고 여기서 첫번째 비트는 0으로 놓으므로 0100.0001.0000.0101.0000.1010이 되고 이것을 Hex로 표현하면 41-05-0a로 표기된다.

이진수와 십육진수의 변환이 궁금하면 http://en.wikipedia.org/wiki/Bit와 http://en.wikipedia.org/wiki/Hexadecimal에서 확인하기 바란다.

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10. Which of the following is an accurate description of the command copy startup-config ftp://kevin:cisco@192.168.1.74?
a. The configuration on the FTP server is copied to RAM
b. The command is not valid on a Cisco router
c. The configuration file in RAM is copied to an FTP server
d. The configuration file in NVRAM is copied to an FTP server.
e. The configuration on the FTP server is copied to NVRAM.
f. The configuration will be copied from NVRAM to an FTP sever with a filename of Kevin

답은 d이고, CCNA문제이므로 독자들의 자존심을 고려해서 설명은 생략. ㅎ

2010년 4월 30일부터 CCNP를 따기 위한 과목중 하나인 Tshoot과목이 시작되었다.

덤프를 아무리 찾아보려고 해도 찾을 수 없고 기존의 베타버전의 덤프만 존재하는데 그 덤프만이라도 뽑아서 정리해보고자 한다.

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1. Which of the following characteristics describe the BPDU Guard featuer? (Choose all that apply.)

a. A BPDU Guard port should only be configured on ports with PortFast enabled.
b. BPDU Guard and PortFast should not be enabled on the same port.
c. BPDU Guard is used to ensure that superior BPDUs are not received on a swith port.
d. A BPDU Guard port receiving a BPDU will go into err-disable state.
e. A BPDU Guard port receiving a BPDU will be disabled.
f. BPDU Guard can be enabled on any switch port.

BPDU Guard는 PortFast가 설정된 포트에서만 작동되므로 a가 답이 된다. 또한 BPDU Guard는 BPDU를 받을때 disable되므로 e가 정답이 된다.

다음은 BPDU Guard에 대한 내용을 시스코 프레스에서 발췌하였다.

The BPDU Guard feature is enabled on ports configured with Cisco's PortFast feature. The PortFast feature is enabled on ports that connect out to end-user devices, such as PCs, and it reduces the amount of time required for the port to go into the forwarding state after being connected. The logic of PortFast is that a port that connects to an end-user device does not have the potential to create a topology loop. Therefre, the port can go active sooner by skipping STP's Listening and Learning states, which by default take 15 seconds each. Because these PortFast ports are connected to end-user devices, there ports should never receive a BPDU. Therefore, if a port enabled for BPDU Guard receives a BPDU, the port is disabled.

쉽게 설명하면 BPDU를 통해서 Spanning-tree의 값을 정하게 되는데 이러한 프로세스를 생략해주는 것이 BPDU Guard라고 생각하면 이해가 쉬울 것이다.

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2. Which of the following are valid modes of accessing the data plane? (choose all that apply.) a. Serial connection b. Secure Shell c. RADIUS d. Simple Network Management Protocol e. HTTP f. Telnet RADIUS는 authentication서버이므로 다음의 질문에 상관이 없다.

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3. Which ofo the following is not an essential prerequisite for AutoQoS to be correctly applied to an interface? (choose all that apply) a. The interface must be configured as a Multilink PPP interface b. The correct bandwidth should be configured on the interface. c. A QoS policy must not be currently attached to the interface. d. CEF must be enabled. e. AutoQoS must be enabled globally before it can be enabled on the itnerface. f. An IP address must be configured on the interface if its speed is equal to or less than 768 kbps. AutoQoS는 interface에 설정되므로 e가 틀린 답이다. Multilink PPP interface는 AutoQoS에서는 불필요하다.

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4. Which of the following topology situations would be a good candidate for configuring DMVPN?
a. extranet VPN
b. Managed overlay VPN topology
c. Hub-and spoke VPN topology
d. Central-site VPN topology
e. Full mesh VPN topology
f. remote-access VPN topology

다음은 시스코프레스에서 발췌한 부분이다.

Rather than creating a full mesh of VPN connectionso vetween all sites in an enterprise network, you can alternatively use Dynamic Multipoint VPN (DMVPN) technology. DMVPN allows VPN connectinos to be dynamically created on an as-needed basis.
DMVPN solution overcomes the performance issues of a hub-and spoke topology, while simultaneously overcoming the scalability issues presented by a full mesh topoloty.

그래서 답은 full messh VPN topology이다.

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5. Which of the following is not considered a common approach to narrow the field of potential problem causes? (choose teh best answer.)
a. Following the traffic path
b. Top-down
c. Comparing configurations
d. Bottom-up
e. Divide and conquer
f. Examine SLAs

Narrow the field of potential causes는 다음과 같다.
Top-Down / Bottom-Up / Divide and Conquer Method / Following the Traffic Path / Comparing Configurations / Component Swapping
그래서 답은 f이다. 참고로 SLA는 Service-Level Agreement의 약어이다.