您好,欢迎来到江浙沪招生考试网 !

设为首页|加入收藏|联系我们|网站地图|

江浙沪招生考试网

您现在的位置: test4exam >> 历年真题 >> it认证题库 >> 正文

思科认证CISCO 642-611 题库

日期:2015/9/4 13:43:13 来源:本站原创 访问量:
1. Refer to the diagram. How many VRF tables are needed to support three VPNs (Customer A, Customer B, and
a VoIP VPN) with the following requirements:   
A. 1 VRF 
B. 3 VRFs 
C. 4 VRFs 
D. 5 VRFs 
E. 7 VRFs 
Answer:D 
TestInside    642-611
2. Which three statements are correct regarding Layer 2 overlay VPNs and peer-to-peer VPNs? (Choose three.) 
A. Peer-to-peer VPNs require the establishment of virtual circuits to connect the different customer sites together. 
B. Peer-to-peer VPNs require the service provider to participate in the customer routing, accepting customer
routes, transporting them across the service provider backbone, and finally propagating them to other customer
sites. 
C. With peer-to-peer VPNs, the service provider is responsible for transport of Layer 2 frames between customer
sites, and the customer takes responsibility for all higher layers. 
D. The implementation of Layer 2 overlay VPNs is the traditional switched-WAN model, implemented with
technologies like X.25, Frame Relay or ATM. 
E. With Layer 2 overlay VPNs, the service provider is not aware of customer routing and has no information about
customer routes. 
F. It is simple to implement Layer 2 overlay VPNs because the Customer Edge (CE) router just needs a connection
to the Service Provider's Provider Edge (PE) router. 
Answer:BDE 
3. Which type of VPN implementation is simple and cost effective because all sites connect only to the PE router
and as a result optimum routing between sites is enabled by default? 
A. peer-to-peer VPN 
B. overlapping VPN 
C. hub-and-spoke overlay VPN 
D. fully-meshed overlay VPN 
E. client-server VPN 
Answer:A 
4. For which purpose is the command mpls ldp maxhops used? 
A. In large ATM-MPLS networks, the LFIB can become too large and it may be necessary to limit the maximum
diameter of the MPLS LSPs. 
B. Because downstream-on-demand label allocation uses hop count to control loop detection, it maybe necessary
to limit the maximum diameter of the MPLS network. 
C. Because end-to-end delay can cause problems with some voice applications, it may be necessary to limit the
maximum diameter of the MPLS network. 
TestInside    642-611
D. When interconnecting large frame mode MPLS and cell mode networks it may be necessary to limit the
maximum network diameter to prevent forwarding loops. 
Answer:B 
5. Refer to the diagram. What problem can be caused by the second P router summarizing the loopback address of
the egress PE router?  
A. The first P router will be faced with a VPN label which it does not understand. 
B. The second P router will be faced with a VPN label which it does not understand. 
C. The egress PE router will not be able to establish a label switch path (LSP) to the ingress PE router. 
D. A label switch path (LSP) will be established from the ingress PE router to the egress PE router, an event that is
not desirable. 
E. The ingress PE router will not be able to receive the VPN label from the egress PE router via MP-IBGP. 
Answer:B 
6. What is a good definition of Cisco's implementation of an ATM Virtual Path as related to LC-ATM MPLS
support? 
A. designed to establish switch-to-switch connectivity between parts of a public ATM network over a private
network 
B. designed to establish switch-to-switch connectivity between parts of a private ATM network over a public
TestInside    642-611
network 
C. designed to establish router-to-router connectivity between parts of a private ATM network over a public
network 
D. designed to establish router-to-router connectivity between parts of a public ATM network over a private
network 
Answer:B 
7. In reference to the diagram depicting the flow of routing updates in an overlapping VPN, which statement is
true?  
A. Sites A1 and A2 will import all networks with RTs 123:750 and 123:1000. 
B. Sites B1 and B2 will export all networks with RTs 123:760 and 123:1000. 
C. Sites A1 and A2 communicate with Sites B1 and B2 via A-Central and B-Central. 
D. Site A-Central exports RTs 123:750 and 123:1000. 
E. Site B-Central is exporting and importing RT 123:1000 so it can communicate with sites A1 and A2. 
Answer:D
TestInside    642-611
8. Which statement is true about overlapping VPNs? 
A. Sites that participate in more than one VPN import routes with RTs from any VPN in which they participate
and export routes with RTs for all VPNs in which they participate. 
B. Sites that participate in more than one VPN import routes with RTs for all VPNs in which they participate and
export routes with RTs for none of the VPNs in which they participate. 
C. Sites that participate in more than one VPN only import routes with RTs for all VPNs in which they participate. 
D. None of the above statements are correct regarding overlapping VPNs. 
Answer:A 
9. Refer to the graphic. CE-2 is using a dedicated sub-interface implementation for Internet access. In this case,
PE-2 will need to establish VPNv4 BGP neighbor relationships with which other router(s)?  
A. PE-1 only 
B. PE-IG only 
C. PE-1 and PE-IG 
D. PE-1 and CE-2 
TestInside    642-611
Answer:A 
10. In a central services topology, which routes do client VRFs contain? 
A. routes from the client site, but not from the server site 
B. routes from the server site, but not from the client site 
C. routes from both the client site and the server site 
D. only EBGP routes from either the client site or the server site 
Answer:C 
11. On a dedicated subinterface implementation, PE-2 must establish an address-family vrf IPv4 BGP neighbor
relationship with which router?  
A. CE-1 
B. CE-2 
C. PE-1 
D. PE-IG 
TestInside    642-611
E. CE-1 and CE-2 
F. PE-1 and PE-IG 
Answer:B 
12. Which component of MPLS architecture is a simple label-based forwarding engine that is independent of the
type of routing protocol or label exchange protocol? 
A. control plane 
B. data plane 
C. routing plane 
D. forwarding plane 
Answer:B 
13. Which kind of link does a Layer 3 overlay VPN use? 
A. emulated point-to-point 
B. dedicated point-to-point 
C. point-to-multipoint 
D. permanent virtual circuits 
Answer:A 
14. What is true about how MPLS implementations support different applications? 
A. The applications only differ in the control plane. 
B. The forwarding plane is customized for each application. 
C. MPLS VPNs require RSVP. 
D. In general a FEC is assigned to a label. 
Answer:A 
15. What are two drawbacks when the Internet is accessed through a dedicated subinterface implementation?
(Choose two.) 
A. The VRF will leak routes into the global routing table. 
B. The P router must run both an IGP and BGP. 
C. The PE routers must perform Internet routing. 
TestInside    642-611
D. A limited set of Internet services will be implemented. 
E. A separate physical link or specific WAN encapsulation is required. 
Answer:CE 
16. In the diagram, Internet access is through a dedicated subinterface implementation. Which of its routing tables
will PE-2 use to forward packets from Site-2 to Site-1?  
A. the global routing table 
B. the VPNv4 routing table 
C. the VRF A routing table 
D. the VRF A FIB 
E. the PE-IG routing table 
Answer:C 
17. In the diagram, the Internet is accessed through a dedicated Internet VPN implementation. Which routing table
will PE-IG use to forward packets from the Internet to Site-2? 
TestInside    642-611 
A. Global routing table 
B. VPNv4 routing table 
C. VRF A routing table 
D. VRF Internet routing table 
Answer:D 
18. What best describes wholesale Internet access service? 
A. an ISP that uses the IP transport infrastructure of another service provider to reach the customers 
B. an ISP that provides broadband access (like DSL or cable) directly to the customers 
C. an ISP that provides both MPLS VPN and Internet access simultaneously to the customers 
D. an ISP that provides a managed firewall service to the customers 
E. an ISP that provides managed CE services to customers 
Answer:A 
19. The exhibit shows a topology where the customer is using Internet access through a central firewall at their
TestInside    642-611
central site. If the customer's MPLS VPN and the Internet access traffic share the same service provider backbone,
which two of the following statements are true? (Choose two.)  
A. Customer Internet traffic can cross the service provider backbone twice, first as VPN traffic and then as
Internet traffic. 
B. Each customer site CE router must perform NAT if the customer is using private IP addresses. 
C. Suboptimal routing of the customer's VPN traffic will occur. 
D. The PE routers will need to exchange both VPNv4 and IPv4 BGP routing updates. 
E. BGP must be used as the routing protocol between the CE and PE routers. 
Answer:AD 
20. A pair of MPLS routers, operating in the default frame-mode, are connected over two parallel links. Which of
the following describes what will happen when they try to establish LDP sessions? 
A. Only one LDP session will be established. 
B. Multiple LDP sessions, one for each link, will be established and the TCP traffic will be load balanced between
the links. 
C. Multiple LDP sessions, one for each link, will be established, but only the one with the highest IP address will
be active. 
D. Multiple LDP sessions, one for each link, will be established, but only the one with the best metric will be
active. 
Answer:A 
21. Which two of the following statements regarding LDP are true? (Choose two.) 
TestInside    642-611
A. LDP can also be used between nonadjacent routers using multicast LDP hello messages. 
B. LDP does not require periodic hello messages once the LDP session has been established between the LDP
peers. 
C. LDP hello messages use TCP packets with a destination port number of 646. 
D. Multiple sessions can be established between a pair of LSRs if they use multiple label spaces. 
E. Per-platform label space can be identified by a label space ID of 0 in the LDP identifier field. 
Answer:DE 
22. Refer to the exhibit. Which two of the following statements about the MPLS configurations are true? (Choose
two.)  
A. The VPI range being configured is the default VPI range. 
B. The router is missing the mpls label protocol ldp configuration command on its ATM 0/0.1 subinterface to
make it an LC-ATM enabled subinterface. 
C. There is a problem with the configurations because the control VC should be set to 0 32 instead. 
D. The ATM switch is using VC merge since VC merge is enabled by default. 
E. For MPLS label allocations, both VPI 6 and 7 can be used. 
Answer:DE 
23. A PE router is running EIGRP with its MPLS VPN customer. What is wrong with the following EIGRP
configuration on the PE router? 
TestInside    642-611 
A. The autonomous-system as-number command is missing under the address-family. 
B. The network 10.0.0.0 command should be configured under the router eigrp configuration mode and not under
the address-family. 
C. The redistribute bgp 65200 metric 10000 100 255 1 1500 command should be configured under the router eigrp
configuration mode and not under the address-family. 
D. The address-family ipv4 vrf testvpn command should be changed to address-family vpnv4 vrf testvpn. 
E. The EIGRP AS number (100) does not match the BGP AS number (65100). 
Answer:A 
24. Refer to the configuration shown in the graphic. Router R1 is supposed to selectively attach an additional RT
of 115:301 to all export routes matched by access-list 10. The configuration is currently not working as intended.
Which two items are wrong with the configuration? (Choose two.)  
A. The route-map is missing the route-map RTMAP permit 20 statement. 
B. The vrf configuration is missing the export map RTMAP command. 
C. The vrf configuration is missing the route-target export 115:301 command. 
TestInside    642-611
D. The rd 115:300 command is not correct. 
E. The set extcommunity rt 115:301 command is not correct. 
F. The route-target both 115:300 command is not correct. 
Answer:BE 
25. Refer to the graphic. In which type of MPLS VPN are customers A and B participating?  
A. overlapping MPLS VPN 
B. simple MPLS VPN 
C. central services MPLS VPN 
D. overlay MPLS VPN 
E. managed CE service MPLS VPN 
Answer:A 
26. What is the difference in implementation between a managed CE services MPLS VPN and a central services
MPLS VPN? 
A. RD assignment 
B. selective routes export 
C. selective routes import 
D. MP-BGP route redistribution filtering 
E. CE-PE routing process 
TestInside    642-611
F. none 
Answer:B 
27. Refer to the exhibit. Client_1 is supposed to participate in a central service MPLS VPN. What import and
export RTs are required in the Client_1 VRF?  
A. route-target both 123:101 
route-target export 123:303 
route-target import 123:203 
B. route-target both 123:101 
route-target export 123:203 
route-target import 123:303 
C. route-target both 123:101 
route-target both 123:103 
D. route-target both 123:203 
route-target both 123:303 
E. route-target both 123:103 
route-target export 123:303 
route-target import 123:203 
F. route-target both 123:103 
route-target export 123:203 
TestInside    642-611
route-target import 123:303 
Answer:A 
28. In situations where cost prohibits having separate physical links for VPN and Internet traffic, what are the two
recommended methods for creating two logical links over a single physical link? (Choose two.) 
A. the use of Frame Relay subinterfaces 
B. the use of 802.1q trunking on LAN interfaces 
C. the use of GRE tunnel interfaces 
D. the use of PPP multilink interfaces 
E. the assignment of two VRFs on the same physical interface 
Answer:AB 
29. What benefit does AToM provide to the service provider's customers? 
A. By supporting Layer 2 VPNs, customers maintain control of their site-to-site routings over the WAN. 
B. By supporting Layer 3 VPNs, a full mesh of virtual circuits will not be required between the different customer
sites to enable optimal routing. 
C. By supporting secured Layer 3 VPNs, customers do not have to deal with the complexity of configuring IPSec. 
D. By supporting MPLS traffic engineering over ATM, customers can better utilize their WAN link. 
E. By supporting Diff-Serv QoS, AToM allows customers to deploy voice/video applications across the WAN. 
Answer:A 
30. What is a benefit of CEF switching? 
A. CEF supports IP source prefix-based switching using the FIB. 
B. CEF uses less memory than fast switching uses. 
C. CEF is less CPU intensive than fast switching is. 
D. CEF provides Netflow statistics with minimum CPU overhead. 
E. CEF allows multiple data planes to share a common control plane. 
Answer:C 
31. When nonadjacent LDP neighbors are used for implementing an MPLS traffic engineering solution, how are
the nonadjacent LDP neighbors discovered? 
TestInside    642-611
A. using multicast CR-LSP (constraint-based LSP) 
B. using unicast CR-LSP (constraint-based LSP) 
C. using multicast LDP hello messages 
D. using unicast LDP hello messages 
E. using multihop MP-IBGP 
F. using multihop MP-EBGP 
Answer:D 
32. What are two concerns when implementing CEF switching? (Choose two.) 
A. increased CPU utilization from maintaining the FIB table 
B. increased memory requirement 
C. the requirement to disable other IOS features such as NBAR and MQC 
D. increased memory requirement on the VIP when implementing DCEF 
E. configuration complexity 
F. troubleshooting complexity because of the many tables that CEF maintains 
Answer:BD 
33. With MPLS VPN-aware NAT, what additional information is tracked inside the NAT translation table? 
A. RD information 
B. RT information 
C. VRF information 
D. Multi-protocol BGP prefixes 
E. MPLS Labels 
Answer:C 
34. What is the purpose of the global configuration command, ip dhcp relay information option vpn? 
A. enables the DHCP relay agent to insert the VPN suboptions to the BOOTP request 
B. enables the DHCP relay agent to convert the broadcast DHCP request to a unicast DHCP request to a shared
DHCP server 
C. enables the DHCP relay agent to perform VRF-aware NAT before forwarding the DHCP request to a shared
DHCP server 
TestInside    642-611
D. enables ODAP (On-Demand Address Pool) on the DHCP relay agent 
Answer:A 
35. What are three characteristics of overlay VPNs? (Choose three.) 
A. Service provider infrastructure appears as point-to-point links to the customer routers. 
B. Routing protocols run directly between the customer routers. 
C. Implementing optimum routing between customer sites requires a partial mesh of virtual circuits. 
D. Service provider PE routers use route filtering to isolate between different customers. 
E. Service provider does not participate in customer routing. 
Answer:ABE 
36. Which of the following could be called a VPN identifier in the MPLS/VPN architecture? 
A. route target 
B. route distinguisher 
C. VRF 
D. VPN IPv4 address 
E. BGP site-of-origin (SOO) extended community attribute 
Answer:A 
37. What best describes the following configuration example of allowas-in?  
A. permits incoming BGP updates defined by access-list 2 
B. permits incoming BGP updates defined by class-map 2 
C. permit incoming BGP updates defined by route-map 2 
D. permits incoming BGP updates with no more than two occurrences of AS 100 in the AS path 
E. permits incoming BGP updates with no more than two occurrences of AS 123 in the AS path 
Answer:D
TestInside    642-611
38. Which three statements correctly describe a route target (RT)? (Choose three.) 
A. An RT is an extended BGP community. 
B. An RT is a 64-bit prefix prepended to a IPv4 address enabling different customers to share the same IP address
pool. 
C. An RT is attached to IPv4 routing updates for indication of MPLS VPN membership. 
D. Multiple RTs can be attached to a single VPNv4 BGP routing update. 
E. Each VRF on a PE router can have multiple import RTs configured. 
F. Export RTs are manually configured on the CE routers. 
Answer:ADE 
39. The following partial output is a PE router configuration related to the OSPF process. During troubleshooting,
you notice that the OSPF routes from the remote sites are not showing up in the local CE router. 
What is a problem that can cause this issue? 
A. The output is missing the metric option in the redistribute command. 
B. The output is missing the metric-type option in the redistribute command. 
C. The output is missing the subnet option in the redistribute command. 
D. The output is missing the vrf option in the redistribute command. 
E. The OSPF network statement is not correct. 
F. The OSPF routing process is missing the address-family ipv4 vrf ABC configuration. 
Answer:C 
40. Which four of the following questions need to be answered during the MPLS VPN troubleshooting process?
(Choose four.) 
A. Are the VPNv4 routes propagated to the other PE routers? 
B. Are the CE routes received by the PE and inserted into the PE VRF? 
C. Are the CE routes received by the PE router redistributed into the PE global BGP table? 
D. Are the VPNv4 routes redistributed from MPBGP into the PE-CE routing protocol? 
E. Are the VPNv4 routes inserted into the VRF on the other PE routers? 
TestInside    642-611
F. Are the PE routers enabled for propagating IPv4 routing updates between them? 
Answer:ABDE
相关阅读

Copyright ©2013-2015 江浙沪招生考试网 All Rights Reserved.
地址: 苏州市姑苏区阊胥路483号(工投创业园)  电话:0512-85551931 邮编: 214000
邮箱: [email protected] 版权所有:苏州迈峰教育科技有限公司 苏ICP备15050684号-2