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思科认证Cisco 642-055 题库

日期:2015/8/23 19:57:50 来源:本站原创 访问量:
1. Which two commands can you use to confirm the native VLAN on the active trunk interface
GigabitEthernet0/1 if only user EXEC privileges are available? (Choose two.) 
A. show vlan 
B. show vlan dot1q tag native 
C. show interface GigabitEthernet0/1 trunk 
D. show interface GigabitEthernet0/1 switchport 
E. show interface GigabitEthernet0/1 capabilities 
Answer: CD 
2. Refer to the exhibit. Assuming that Switch_A is correctly configured, which two configuration options, when
configured on the GigabitEthernet2/1 and GigabitEthernet2/2 interfaces of Switch_B, will allow the EtherChannel
bundle to come up? (Choose two.)  
A. channel-group 10 mode active 
B. channel-group 10 mode auto 
C. channel-group 10 mode desirable 
D. channel-group 10 mode on 
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E. channel-group 10 mode passive 
Answer: BC 
3. Refer to the exhibit. Which command will correctly set the holdtime for HSRP Group 11 to 300 milliseconds?  
A. standby 11 timers holddown msec 100 
B. standby 11 timers msec 300 msec 100 
C. standby 11 timers msec 100 msec 300 
D. standby 11 timers msec 100 holddown 
Answer: C 
4. Refer to the exhibit. Users complain that they intermittently lose data and connections to important servers.
After investigation, you discover that the 802.1Q trunk between DSW111 and ASW1 is down. Even though the
HSRP group 11 is being serviced by DSW112, you discover that the SVI for VLAN 11 is in the up state on
DSW111. Which three Cisco Catalyst IOS commands should you use on DSW111 to find the source of this
problem? (Choose three.)  
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A. show vtp status 
B. show interfaces vlan 11 
C. show standby vlan 11 brief 
D. show spanning-tree vlan 11 
E. show interfaces <fast | gig> mod/port trunk 
Answer: BDE 
5. Refer to the exhibit. What is the HSRP state and priority of this interface after HSRP reaches its steady state?  
A. Active, Priority 151 
B. Active, Priority 201 
C. Active, Priority 251 
D. Standby, Priority 151 
E. Standby, Priority 201 
F. Standby, Priority 251 
Answer: D 
6. When you enter the interface command auto qos voip cisco-phone on a port at the edge of a network, how does
the Cisco Catalyst switch detect if a Cisco IP Phone is connected to the port? 
A. by snooping the CoS marking on the incoming frames 
B. by using RTP hello messages between the switch port and the Cisco IP Phone 
C. by using CDP 
D. by using DHCP snooping 
E. by snooping the incoming 802.1Q VLAN tag 
Answer: C
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7. Refer to the exhibit. What is wrong with the Cisco Catalyst switch 802.1x authentication configuration?  
A. The authentication method list is not correctly enabled for dot1x. 
B. 802.1x authentication is not enabled globally on the switch. 
C. The Fa0/1 interface is not configured as an 802.1Q trunk port. 
D. The guest VLAN is not correctly configured. 
E. dot1x reauthentication is not globally enabled. 
Answer: A 
8. On a Cisco Catalyst switch, which configuration command is used to apply a VACL named "test" to filter the
traffic within VLAN100? 
A. interface vlan 100 
ip access-group test 
B. interface vlan 100 
ip access-group test in 
C. interface vlan 100 
ip access-group test out 
D. vlan filter test vlan-list 100 
E. vlan access-map test 100 
Answer: D 
9. What is the function of the no switchport Catalyst switch interface configuration command? 
A. switches the port from access mode to trunk mode 
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B. converts the port from physical Layer 2 port to physical Layer 3 port 
C. enables the interface for Layer 2 switching 
D. disables the interface to prevent traffic flow 
E. clears all the configurations on the interface 
Answer: B 
10. On the Catalyst 6500 Series switch, which command is used to establish a console connection to the Firewall
Services Module? 
A. telnet 
B. connect 
C. session 
D. ssh 
E. login 
Answer: C 
11. Which two statements are correct in verifying SPFv3 IPv6 routing configurations? (Choose two.) 
A. OSPFv3 router ID is now 128 bits instead of 32 bits. 
B. OSPFv3 area ID and link-state ID are now 128 bits instead of 32 bits. 
C. OSPFv3 is enabled per-link, not per-network. 
D. OSPFv3 requires router to be running CEF. 
E. When configuring a broadcast interface, OSPFv3 requires a list of OSPFv3 neighbors to be manually
configured. 
Answer: CD 
12. Which three of these items are found within the router advertisement message of IPv6 stateless
autoconfiguration? (Choose three.) 
A. /64 prefix that can be used on the link and the lifetime of the prefix 
B. IPv6 DHCP server address information 
C. flags indicating the kind of autoconfiguration that can be done by hosts 
D. default router information 
E. IPv6 DNS server address information 
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Answer: ACD 
13. Referring to the debug output shown below, which one of the statements is correct? 
R1# debug ipv6 icmp 
ICMPv6: Sending echo request to 2001:DB8:C18:1::D0C 
ICMPv6: Received ICMPv6 packet from 2001:DB8:C18:1::D0C, type 129 
ICMPv6: Received ICMPv6 packet from FE80::260:3EFF:FE47:1530, type 134 
A. FE80::260:3EFF:FE47:1530 is the site-local address of R1. 
B. 2001:DB8:C18:1::D0C is a link-local address. 
C. The last ICMP message received is a router advertisement message. 
D. The type 129 ICMP echo reply message indicates an MTU error. 
E. The type 129 message is an ICMP redirect message. 
Answer: C 
14. Which three of these items are IPv6 transition mechanisms? (Choose three.) 
A. NATv6 
B. PATv6 
C. ISATAP 
D. automatic 4to6 relay tunnels 
E. dual stack configurations 
F. manually configured overlay tunnels 
Answer: CEF 
15. What are four advantages to using tunnel brokers in an IPv6 transition environment? (Choose four.) 
A. Tunnel broker configuration is automated in Cisco IOS. 
B. IPv6 enabling a node looks automatic to the end user. 
C. Tunnel brokers make it simpler for nontechnical users to deploy manual tunnels. 
D. Tunnel information is sent via IPv4. 
E. Tunnel brokers automatically provide configuration parameters to peer routers. 
Answer: BCDE 
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16. How many subnets are possible in an enterprise that has just been assigned an IPv6 prefix by its ISP? 
A. 256 
B. 1024 
C. 4096 
D. 16384 
E. 65536 
F. 16777216 
Answer: E 
17. Which keyword is used with the show ip bgp neighbors [keyword] command to display all routes that are
received and accepted from a neighbor? 
A. paths 
B. routes 
C. received-routes 
D. accepted-routes 
E. advertised-routes 
Answer: B 
18. Which Cisco IOS command is used to troubleshoot a problem in which a BGP session stays in the active
state? 
A. debug ip bgp events 
B. debug ip tcp events 
C. debug ip bgp updates 
D. debug ip tcp updates 
E. debug ip bgp transactions 
F. debug ip tcp transactions 
Answer: F 
19. What is the most likely reason that an IBGP route that has been selected as a best route is not entered into the
IP routing table? 
A. The next-hop address is unreachable. 
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B. No loopback interface has been configured on a router. 
C. BGP synchronization has been enabled. 
D. Route reflectors are not passing updates properly. 
Answer: C 
20. Which command is used to view IPv6 parameters related to the BGP process? 
A. show ip bgp 
B. show ipv6 bgp 
C. show bgp ipv6 
D. show ip bgp ipv6 
E. show protocols ipv6 
Answer: C 
21. Which four of these items will the show ipv6 interface tunnel0 command provide? (Choose four.) 
A. link-local address 
B. global unicast address of the tunnel endpoint 
C. global unicast address of the tunnel destination 
D. multicast joined group addresses 
E. MTU 
F. tunnel encapsulation type 
Answer: ABDE 
22. Which keyword is used with the debug ipv6 [keyword] command to troubleshoot neighbor discovery
problems? 
A. nd 
B. icmp 
C. packet 
D. discovery 
E. transaction 
Answer: A 
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23. Refer to the exhibit. A Catalyst 6500 is configured to aggregate two ports into an EtherChannel. Based on the
configuration snippet, which of these statements is true regarding the EtherChannel?  
A. It is a Layer 2 EtherChannel autocreated using LACP. 
B. It is a Layer 2 EtherChannel with no autocreation. 
C. It is a Layer 2 EtherChannel autocreated using PAgP. 
D. It is a Layer 3 EtherChannel autocreated using LACP. 
E. It is a Layer 3 EtherChannel with no autocreation. 
F. It is a Layer 3 EtherChannel autocreated using PAgP. 
Answer: E 
24. When an IP packet is Layer 3-switched from a source in one VLAN to a destination in another VLAN, which
field in a packet will be rewritten? 
A. Layer 2 TTL 
B. Layer 3 TTL 
C. Layer 3 source address 
D. Layer 3 transport protocol 
E. Layer 3 destination address 
Answer: B 
25. Which of these tools should you use to compress VoIP packets on a low-speed Frame Relay circuit? 
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A. RTP header compression 
B. TCP header compression 
C. FRF.9 payload compression 
D. Predictor payload compression 
E. Cisco proprietary payload compression 
Answer: A 
26. What is required to enable fragmentation of large FTP packets when voice quality on the network is affected
by FTP transfers? 
A. Configure MLP on the Frame Relay interfaces. 
B. Configure TCP header compression on interfaces. 
C. Fragmentation is not supported with service internetworking. 
D. Configure FRF.12 fragmentation on the Frame Relay interfaces. 
Answer: A 
27. Refer to the exhibit. You have a Cisco router directly connected to a non-Cisco router via a leased T1 line. The
service provider has validated that the T1 is operational. What should be completed for communications between
routers to commence?  
A. Reload both routers. 
B. Reset the interface on both routers. 
C. Enable Frame Relay on both routers. 
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D. Enable PPP encapsulation on both routers. 
E. Configure a routing protocol on both routers. 
Answer: D 
28. How can Cisco NetFlow be used to aid in the operation and troubleshooting of QoS issues? 
A. NetFlow can report on the number of traffic matches for each class map in a configured QoS policy
configuration. 
B. NetFlow records can be used to understand traffic profiles per class of service for data, voice, and video traffic. 
C. NetFlow can discover the protocols in use and automatically adjust QoS traffic classes to meet policy-map
requirements. 
D. NetFlow can be configured to identify voice and video traffic flows and place them into a low-latency queue
for expedited processing. 
Answer: B 
29. Refer to the exhibit. You have a Cisco router and a non-Cisco router directly connected to a service provider
cloud. You want to set up dual connectivity into the corporate network. Which protocol must you configure?  
A. Hot Standby Router Protocol 
B. Gateway Load Balancing Protocol 
C. Virtual Router Redundancy Protocol 
D. Multigroup Hot Standby Router Protocol 
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Answer: C 
30. Refer to the exhibit. You have a non-Cisco switch that is not communicating properly while connected to the
distribution-layer Cisco switching fabric. Which two best-practice actions can you take to overcome this problem?
(Choose two.)  
A. Turn off MST (802.1s) on all switches. 
B. Turn on MST (802.1s) on all switches. 
C. Turn on RSTP (802.1w) on all switches. 
D. Turn off RSTP (802.1w) on all switches. 
Answer: BD 
31. When implementing MPLS VPNs between CE and PE routers, which of these statements is correct? 
A. If using IS-IS as the PE-CE routing protocol, no redistribution is required. 
B. If using static routes between the CE and PE routers, no redistribution of other VPN routes is required. 
C. If the PE-CE protocol is not BGP, redistribution of other VPN routes from MP-BGP is required. 
D. If RIP is the routing protocol that is used between the PE-CE routers, no redistribution is required, but any
other protocol will require redistribution. 
E. If using OSPF or EIGRP as the PE-CE routing protocol, redistribution is not required, but any other protocol or
static route will require redistribution. 
Answer: C
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32. Refer to the exhibit. Which two of these events will be the result of issuing the above command? (Choose
two.)  
A. A 64-bit IPv4 prefix will be created. 
B. The route distinguisher will be used to indicate VPN membership. 
C. Extended BGP communities will be used to encode route distinguishers. 
D. A 96-bit VPNv4 prefix will be created and propagated across the IP network. 
E. The route distinguisher is 64 bits and will be prepended to an existing IPv4 route to make it globally unique. 
Answer: DE 
33. Refer to the exhibit. In analyzing the configuration of the router, which three of these statements are correct?
(Choose three.)  
A. Neighbor 172.16.32.14 will receive VPNv4 routes. 
B. Neighbor 172.16.32.15 will receive Internet routes. 
C. Neighbor 172.16.32.15 will receive VPNv4 routes. 
D. Neighbor 172.16.32.27 will receive VPNv4 routes. 
E. Neighbor 172.16.32.27 will receive Internet routes. 
F. Neighbor 172.16.32.14 will receive both VPNv4 and Internet routes. 
Answer: CDE 
34. Refer to the exhibit. As shown in the configuration, RIP is being used as the PE-CE routing protocol. Which of
these statements is correct? 
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A. Though preferred, it is not necessary that the RIP parameters be specified in the VRF. 
B. Though RIPv2 is specified in the configuration, any version of RIP supports VRFs. 
C. On the receiving end, the RIP hop count is copied into a BGP extended community attribute. 
D. On the sending end, the RIP hop count is copied into the BGP multi-exit discriminator attribute. 
E. Because RIP is being used as the PE-CE routing protocol, the redistribution commands in the configuration are
not necessary because redistribution occurs automatically between RIP and BGP. 
Answer: D 
35. When EIGRP is used as the PE-CE routing protocol, which of these statements is correct? 
A. Configuration of the VPN is only required on the PE router. 
B. EIGRP can be used only as the PE-CE routing protocol if the PE and CE routers are in the same AS. 
C. When using EIGRP as the PE-CE routing protocol, EIGRP does not require a VRF. 
D. Unlike other routing protocols that are used between PE and CE routers, EIGRP supports backdoor links. 
E. Other EIGRP AS routes are automatically advertised to the CE router and do not require a redistribution
configuration command to be configured. 
Answer: A 
36. When BGP is used as the PE-CE routing protocol, which of these statements is correct? 
A. On PE routers, the CE EBGP neighbors are configured in the VRF context. 
B. On the CE router, PE neighbors must be configured in the VRF context on the CE router. 
C. On PE routers, the CE IBGP neighbors are configured in the global BGP configuration. 
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D. When using BGP as the PE-CE routing protocol, only public AS numbers can be used when configuring the
BGP neighbor relationships. 
E. A separate BGP process must be used on the PE routers for CE routers so that they do not use the same BGP
routing process as that used for the PE router's other provider neighbors. 
Answer: A 
37. Refer to the exhibit. Which of these statements is correct regarding the output display shown in the exhibit?  
A. MPLS is not operational because there are no discovered sources. 
B. Interface S0/0.112 has been configured for LDP passive mode. 
C. The MPLS neighbor connected to S0/0.111 is misconfigured. 
D. The MPLS LDP protocol may not have been configured on the S0/0.112 adjacent LSR. 
E. In the Local LDP ID display 192.168.1.17:0, the 0 indicates the beginning LDP label that will be assigned. 
Answer: D 
38. Refer to the exhibit. MPLS has been enabled on router PE11. Which of these statements is correct regarding
the output display shown in the exhibit?  
A. CEF switching is not needed for MPLS operation. 
B. CEF switching is only needed to forward labeled packets. 
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C. CEF switching is needed on both ingress and egress interfaces on which MPLS is enabled. 
D. Interface-level CEF switching is needed only on egress interfaces that are sending IP packets on which the
egress LSR performs the label imposition process. 
E. Interface-level CEF switching is needed only on ingress interfaces that are receiving IP packets on which the
ingress LSR performs the label imposition process. 
Answer: E 
39. Refer to the exhibit. Which of these statements is correct regarding the output display shown in the exhibit?  
A. Label 19 has been advertised by PE11 and is assigned to prefix 150.1.12.16. 
B. For destination 150.1.12.16, label 19 will be on the incoming packet and PE11 will impose label 21. 
C. For destination 192.168.1.64, label 19 will be on the incoming packet and PE11 will impose label 17. 
D. For destination 150.1.12.16, PE11 has sent information to its neighbor that it will impose label 21 on packets
for that destination. 
Answer: C 
40. Refer to the exhibit. Analyze the two traceroutes that are displayed. Which of these statements is correct in
describing what most likely caused the traceroute differences?  
A. Do not fragment has been configured on PE11. 
B. MPLS has been disabled on routers P11 and P12. 
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C. An access list has been created on P11 to block traceroutes from PE11. 
D. The no mpls ip propgate-ttl local command has been configured on PE11. 
E. ICMP has been disabled on the intermediary routers between PE11 and PE12. 
Answer: D 
41. Refer to the exhibit. Which two of these statements are correct? (Choose two.)  
A. PE11 originated label 20. 
B. PE11 originated label 21. 
C. The PE11 upstream neighbor originated label 21. 
D. The PE11 downstream neighbor originated label 20. 
E. PE11 will append label 21 to incoming packets labeled 32. 
F. PE11 will impose label 20 on incoming packets labeled 32. 
Answer: AC 
42. Refer to the exhibit. You are migrating a network from IGRP to OSPF. What must you do to ensure that
connectivity and reachability of all networks is maintained between routing protocols when OSPF has the longer
subnet mask?  
A. Use the default metric of 1. 
B. This scenario should not present any reachability problems if the autonomous systems are the same. 
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C. Add multiple static routes in the gateway router pointing to the OSPF network. 
D. Add a static route in the gateway router for 128.103.35.0/24 pointing to null0. 
Answer: D 
43. Referring to the partial Cisco Catalyst switch configuration shown, which two of these statements are correct?
(Choose two.)  
A. A router connected to the fastethernet 1/4 interface will be able to communicate with hosts connected to
interface fastethernet 1/1, 1/2, and 1/3. 
B. A router connected to the fastethernet 1/4 interface will not be able to communicate with the host connected to
interface fastethernet 1/3. 
C. Hosts connected to interface fastethernet 1/1 and 1/2 can communicate with each other. 
D. Hosts connected to interface fastethernet 1/1, 1/2, and 1/3 can communicate with each other. 
Answer: AC 
44. In MPLS networks, what is the benefit of disabling TTL propagation? 
A. to improve MPLS convergence time 
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B. to improve the IGP convergence time 
C. to hide visibility to the core (provider) routers in the MPLS network 
D. to provide a visible extension of IP TTL functionality in an MPLS-enabled domain 
E. to provide a visible extension of MPLS TTL functionality in a non-MPLS-enabled domain 
Answer: C 
45. What is the purpose of the int-num variable in the Cisco IOS interface configuration command mpls
l2transport route when you configure a Cisco 7600 Series router to do Ethernet over MPLS? 
A. It specifies the incoming interface of the Layer 2 traffic to be transported over the MPLS backbone. 
B. It specifies the interface address of the remote router. 
C. It specifies the desired VLAN interface number. 
D. It specifies the outgoing interface through which to route the EoMPLS traffic. 
Answer: B 
46. You have just reinstalled a VIP 6-80 in a Cisco 7500 Series router. What must you do to bring up the port
adapter interfaces? 
A. Any interfaces not previously configured must be manually configured and brought online. 
B. All interfaces must be manually brought online, even those previously configured. 
C. The previous VIP configuration must be reloaded to bring interfaces online. 
D. All interfaces are online by default once the VIP is up and running normally. 
Answer: A 
47. With a VPN Accelerator Module 2+ (VAM2+) installed in a Cisco 7200 series router, what will be the
resulting action when entering the command no crypto engine accelerator slot number? 
A. removes the VAM2+ crypto engine feature and disables the associated configuration commands from the router 
B. disables the crypto engine hardware acceleration, resulting in all crypto functions to be performed in software 
C. disables dual VAM2+ hardware stateful failover capabilities 
D. disables OIR on the VAM2+ module 
Answer: D 
48. What are three pieces of information that the Cisco IOS show environment command displays on a Cisco ISR
TestInside    642-055
router? (Choose three.) 
A. installed hardware 
B. system load statistics 
C. hardware serial number 
D. ambient room temperature 
E. the status of the system fans 
F. main power supply condition 
Answer: BEF 
49. Refer to the exhibit. Two switches connected to each other are having serious performance issues on the link.
Which command(s) can you issue at switch B to correct this problem?  
A. set port duplex 1/1 full 
B. no set port duplex 1/1 auto 
C. set port speed 1/1 10
set port duplex 1/1 full 
D. no set port duplex 1/1 auto
set port duplex 1/1 full 
Answer: C 
50. What are three pieces of information that the Cisco IOS show inventory command displays on a Cisco ISR
router? (Choose three.) 
A. installed hardware 
B. Unique Device Identifier 
C. system internal temperature 
D. main power supply condition 
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E. the status of installed hardware 
F. installed hardware serial numbers 
Answer: ABF 
51. Refer to the exhibit. On the switch named CatosSwitch, how many VLANs did the administrator manually
configure?  
A. 1 
B. 2 
C. 3 
D. 7 
Answer: B 
52. What are two requirements to perform a warm Cisco IOS upgrade on a Cisco ISR router? (Choose two.) 
A. at least one enabled Ethernet interface 
B. Cisco IOS version 12.3(2)T or greater 
C. physical access to the router to be upgraded 
D. enough memory to decompress the new Cisco IOS image 
E. internal flash memory equaling two times the space required for the current Cisco IOS image 
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Answer: BD 
53. What is a new feature of the Cisco ISR router? 
A. FICON ports 
B. Cisco CallManager 5.0 support 
C. warm Cisco IOS upgrade feature 
D. packet voice data module 
E. advanced integration module 
Answer: C
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