Cisco 642-902 Online Practice Questions and Exam Preparation

Cisco 642-902 Online Questions & Answers

• Question 311:

  Refer to the exhibit.

  

  R1 accesses the Internet using E0/0. You have been asked to configure R1 so that a default route is generated to its downstream neighbors (191.0.0.1 and 192.0.0.1). Which commands would create this configuration?

  A. router eigrp 190 redistribute static ! ip route 0.0.0.0 0.0.0.0 Null0
  B. ip default-network 20.0.0.0
  C. router eigrp 190 redistribute static ! ip route 0.0.0.0 255.255.255.255 Null0
  D. ip default-network 20.20.20.0
  A. router eigrp 190 redistribute static ! ip route 0.0.0.0 0.0.0.0 Null0

  ---

  Since you are running EIGRP and you have other routers that need a default route, you can use EIGRP to distribute that without having to program static routes in each. Since 2 are default routes they are only used on the router that they are configured on. The first option has you configure the static route as well as a way to redistribute that route to other routers connecting to you via EIGRP. This will essentially publish this route the same as if it were programmed in with the network x.x.x.x sub-command in the router eigrp 100 routing table.

• Question 312:

  Refer to the exhibit.

  

  Which statement about this neighbor of R1 is true?

  A. OSPFv3 adjacency has been lost, which causes the neighbor to be considered Stale.
  B. Aggregate global addresses are always used between IPv6 neighbors.
  C. OSPFv3 adjacency will not work between link-local addresses.
  D. R1 used ICMP to learn about this neighbor.
  D. R1 used ICMP to learn about this neighbor.

  ---

  ICMP is a ping echo. IPv6 uses ICMP to learn about its neighbor.

• Question 313:

  Refer to the exhibit.

  

  Which three commands should be used on router B1 to redistribute the EIGRP AS 10 routes into RIP? (Choose three.)

  A. router rip
  B. router eigrp 10
  C. redistribute eigrp 10
  D. redistribute rip
  E. default-metric 10000 100 255 1 1500
  F. default-metric 5
  A. router rip
  C. redistribute eigrp 10
  F. default-metric 5

  ---

  Reference: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009487e.shtml#ri p

• Question 314:

  LAB. (IPv6 OSPF Virtual Link Simulation)

  Acme is a small export company that has an existing enterprise network that is running IPv6 OSPFv3. Currently OSPF is configured on all routers.

  However, R4's loopback address (FEC0:4:4) cannot be seen in R1's IPv6 routing table. You are tasked with identifying the cause of this fault and implementing the needed corrective actions that uses OSPF features and does no change the

  current area assignments. You will know that you have corrected the fault when R4's loopback address (FEC0:4:4) can ping from R1 to R4 loopback address.

  

  Check the answer below

  To troubleshoot the problem, first issue the show running-config on all of 4 routers. Pay more attention to the outputs of routers R2 and R3 The output of the "show running- config" command of R2:

  

  The output of the "show running-config" command of R3:

  

  We knew that all areas in an Open Shortest Path First (OSPF) autonomous system must be physically connected to the backbone area (Area 0). In some cases, where this is not possible, we can use a virtual link to connect to the backbone through a non-backbone area. The area through which you configure the virtual link is known as a transit area. In this case, the area 11 will become the transit area. Therefore, routers R2 and R3 must be configured with the area virtual-link command. + Configure virtual link on R2 (from the first output above, we learned that the OSPF process ID of R2 is 1): R2>enable R2#configure terminal R2(config)#ipv6 router ospf 1 R2(config-rtr)#area 11 virtual-link 3.3.3.3 Save the configuration: R2(config-rtr)#end R2#copy running-config startup-config (Notice that we have to use neighbor router-id 3.3.3.3, not R2's router-id 2.2.2.2) + Configure virtual link on R3 (from the second output above, we learned that the OSPF process ID of R3 is 1 and we have to disable the wrong configuration of "area 54 virtual-link 4.4.4.4"): R3>enable R3#configure terminal R3(config)#ipv6 router ospf 1 R3(config-rtr)#no area 54 virtual-link 4.4.4.4 R3(config-rtr)#area 11 virtual-link 2.2.2.2 Save the configuration: R3(config-rtr)#end R3#copy running-config startup-config You should check the configuration of R4, too. R4(config)#ipv6 router ospf 1 R4(config-router)#no area 54 virtual-link 3.3.3.3 R4(config-router)#end After finishing the configuration doesn't forget to ping between R1 and R4 to make sure they work well! Note. If you want to check the routing information, use the show ipv6 route command, not "show ip route".

• Question 315:

  How is authentication handled with OSPFv3?

  A. OSPFv3 for IPv6 authentication is supported by IPv6 IPsec.
  B. OSPFv3 for IPv6 authentication is supported by MD5 authentication.
  C. OSPFv3 for IPv6 authentication is supported by IPv4 IPsec.
  D. OSPFv3 for IPv6 authentication is supported by SHA-1 authentication.
  A. OSPFv3 for IPv6 authentication is supported by IPv6 IPsec.

  ---

  Reference: http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_ospf/configuration/xe- 3s/ip6-route-ospfv3-auth-ipsec-xe.html

• Question 316:

  Study the exhibit carefully.

  

  Router R1 is connected to networks 172.16.1.0 /26 and 172.16.1.64 /27. Based on the partial output in the exhibit, which description is correct?

  A. Router R1 should be reconfigured with an ACL instead of an ip prefix-list command.
  B. Router R1 will advertise both routes.
  C. Router R1 will deny the 172.16.1.0/27 route while permitting the 172.16.1.0/26 route to be advertised.
  D. Router R1 will deny the 172.16.1.0/26 route while permitting the 172.16.1.64/27 route to be advertised.
  C. Router R1 will deny the 172.16.1.0/27 route while permitting the 172.16.1.0/26 route to be advertised.

  ---

  Prefix lists are configured with permit or deny keywords to either permit or deny the prefix based on the matching condition. A prefix list consists of an IP address and a bit mask. The IP address can be a classful network, a subnet, or a single host route. The bit mask is entered as a number from 1 to 32.

  Prefix lists are configured to match an exact prefix length or a prefix range. The ge and le keywords are used to specify a range of the prefix lengths to match, providing more flexible configuration than can be configured with just the network/ length argument. The prefix list is processed using an exact match when neither ge nor le keyword is entered.

  Therefore in this case the exact 172.16.1.0/26 network is permitted while other networks are denied.

  (Reference: http://www.cisco.com/en/US/docs/ios/12_3t/ip_route/command/reference/ip2_i2gt.html)

• Question 317:

  When implementing OSPFv3, which statement describes the configuration of OSPF areas?

  A. In interface configuration mode, the OSPFv3 area ID combination assigns interfaces to OSPFv3 areas.
  B. In router configuration mode, the network wildcard area ID combination assigns networks to OSPFv3 areas.
  C. In interface configuration mode, the IPv6 OSPF process area ID combination assigns interfaces to OSPFv3 areas.
  D. In router configuration mode, the IPv6 OSPF interface area ID combination assigns interfaces to OSPFv3 areas.
  C. In interface configuration mode, the IPv6 OSPF process area ID combination assigns interfaces to OSPFv3 areas.

  ---

  Reference:

  http://www.hh.se/download/18.4cf286ee134f03ddb7b800015/1326882212358/Chapter3_VT 2012.pdf (slide 42)

• Question 318:

  What are the two reasons for the appearance of 0.0.0.0 as the next hop for a network in the show ip bgp command output? (Choose two.)

  A. The network was originated via redistribution of an interior gateway protocol into BGP.
  B. The network was defined by a static route.
  C. The network was learned via IBGP.
  D. The network was learned via EBGP.
  E. The network was originated via a network or aggregate command.
  A. The network was originated via redistribution of an interior gateway protocol into BGP.
  E. The network was originated via a network or aggregate command.

  ---

  "The network was originated via a network or aggregate command" has the next hop of 0.0.0.0. In short, the router on which you use the "network" or "aggregate" command will set the next hop of 0.0.0.0 for that route.

  About redistribution please refer to the Understanding Redistribution of OSPF Routes into BGP:

  http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800943c5.shtml you will see after the network 2.0.0.0 has been redistributed in BGP it has the next hop of 0.0.0.0.

• Question 319:

  Refer to the exhibit. OSPF is running throughout the network. You want to minimize the propagation of LSAs into and out of Area 1. Which OSPF feature would best achieve this goal?

  

  A. stub
  B. totally stubby
  C. NSSA
  D. totally NSSA
  D. totally NSSA

  ---

  We need to redistribute RIP from R1 to Area 1 so Area 3 cannot be a stub or totally stubby area. To minimize the propagation of LSAs into and out of Area 1 we should configure it as a totally NSSA. Notice that a NSSA allows LSA Type 3 and 7

  while a Totally NSSA only allows LSA Type 7

  Note:

  Both Totally Stubby Area and Totally Stubby NSSA do not accept external AS routes or inter- area routes (LSA Types 3, 4 and 5). They recognize only intra-area routes and the default route 0.0.0.0. The main difference between them is Totally

  Stubby NSSA accepts routes from other AS while Totally Stubby Area does not.

  Below summarizes the LSA Types allowed and not allowed in area types:

  

• Question 320:

  When other routing protocol routes are being redistributed into OSPF, what is one of the most common problems?

  A. missing the tag option in the redistribute command.
  B. missing the subnet option in the redistribute command.
  C. missing the metric option in the redistribute command.
  D. misconfiguring the metric-type option in the redistribute command to type-1.
  E. misconfiguring the metric-type option in the redistribute command to type-2.
  B. missing the subnet option in the redistribute command.

  ---

  The point of this question is about the redistribution of OSPF. To redistribute routes from one routing domain into another routing domain, use the redistribute command in router configuration mode. redistribute protocol [process-id] {level- 1 |

  level-1-2 | level-2} [as-number] [metric {metric-value | transparent}] [metric-type type- value] [match {internal | external 1 |

  external 2}] [tag tag-value] [route-map map-tag] [subnets] The subnets keyword tells OSPF to redistribute all subnet routes. Without the subnets keyword, only networks that are not subnetted are redistributed by OSPF.