English FormB CCNA3 Version3.1 Module2 – 2006 fall
1. Which command sequence will enable OSPF in the backbone area for the two Ethernet links on RouterA?
RouterA(config)# router ospf 1
RouterA(config-router)# network 172.16.4.0 0.0.1.255 area 1
***RouterA(config)# router ospf 10
RouterA(config-router)# network 172.16.4.0 0.0.0.255 area 0
RouterA(config-router)# network 172.16.5.0 0.0.0.255 area 0
RouterA(config)# router ospf 10
RouterA(config-router)# area 0 network 172.16.4.0 0.0.1.255
RouterA(config)# router ospf 0
RouterA(config-route)# network 172.16.4.0 0.0.255.255 area 0
RouterA(config)# router ospf 0
RouterA(config-router)# network 172.16.4.0 255.255.255.0
RouterA(config-router)# network 172.16.5.0 255.255.255.0
RouterA(config)# router ospf 1
RouterA(config-router)# network 172.16.4.0 255.255.254.0 area 0
2. How can the OSPF cost for a link be established? (Choose two.)
It is set to 1544 by default for all OSPF interfaces.
***It can be set with the ip ospf cost command.
The configured loopback addresses map to link costs.
It is calculated proportionally to observed throughput capacity of the router.
***It may be calculated using the formula 108/bandwidth.
3. Which router command will display the interface priority value and other key information for the OSPF configuration of the serial 0 interface?
router# show ospf serial 0
router# show interface serial 0 OSPF
router# show ip interface serial 0
***router# show ip ospf interface serial 0
4. Because of security concerns, a network administrator wants to set up authentication between two routers. Which of the following commands will configure Router_A to trust Router_B with a clear text password of apollo?
Router_A(config-if)# ospf authentication-key apollo
Router_A(config-if)# ip authentication-key apollo
Router_A(config-if)# ip ospf authentication apollo
***Router_A(config-if)# ip ospf authentication-key apollo
5. RouterA, RouterB, and RouterC in the diagram are running OSPF on their Ethernet interfaces. Loopback interfaces (Lo 0) are configured as shown. What happens when RouterD is added to the network?
RouterB takes over as DR and RouterD becomes the BDR.
RouterD becomes the BDR and RouterA remains the DR.
RouterD becomes the DR and RouterA becomes the BDR.
RouterC acts as the DR until the election process is complete.
RouterD becomes the DR and RouterB remains the BDR.
***There is no change in the DR or BDR until either current DR or BDR goes down.
6. Refer to the network shown in the diagram. Which command sequence on RouterB will redistribute a Gateway of Last Resort to the other routers in OSPF area 0?
RouterB(config)# router ospf 10
RouterB(config-router)# gateway-of-last-resort 172.16.6.6
RouterB(config)# ip route 0.0.0.0 0.0.0.0 serial 0
***RouterB(config)# ip route 0.0.0.0 0.0.0.0 172.16.6.6
RouterB(config)# router ospf 10
RouterB(config-router)# default-information originate
RouterB(config)# router ospf 10
RouterB(config-router)# default network 172.16.6.6 0.0.0.3 area 0
RouterB(config)# ip route 0.0.0.0 0.0.0.0 172.16.6.6
RouterB(config)# ip default-route 0.0.0.0 0.0.0.0 172.16.6.6
RouterB(config)# router ospf 10
RouterB(config-router)# redistribute ip default-route
7. Which of the following should be considered when troubleshooting a problem with the establishment of neighbor relationships between OSPF routers? (Choose three.)
***OSPF interval timers mismatch
gateway of last resort not redistributed
***interface network type mismatch
no loopback interface configured
administrative distance mismatch
***inconsistent authentication configuration
8. In which types of networks are OSPF DR elections necessary? (Choose two.)
point-to-point
point-to-multipoint
***broadcast multiaccess
***nonbroadcast multiaccess
9. What does OSPF use to reduce the number of exchanges of routing information in networks where large numbers of neighbors are present? (Choose two.)
root router
backup root router
domain router
backup domain router
***designated router
***backup designated router
10. What information can be obtained from the output of the show ip ospf interface command? (Choose three.)
link-state age intervals
***timer intervals
***router ID number
link-state update intervals
***neighbor adjacencies
11. Which of the following are required when adding a network to the OSPF routing process configuration? (Choose three.)
***network address
loopback address
autonomous system number
subnet mask
***wildcard mask
***area ID
12. What speeds up convergence in a network using link-state routing?
***updates triggered by network changes
updates sent at regular intervals
updates sent only to directly connected neighbors
updates that include complete routing tables
13. Why is it difficult for routing loops to occur in networks that use link-state routing?
Each router builds a simple view of the network based on hop count.
Routers flood the network with LSAs to discover routing loops.
***Each router builds a complete and synchronized view of the network.
Routers use hold-down timers to prevent routing loops.
14. Which router is the root of an SPF tree?
border router
nearest neighboring router
***local router
trunk router, as determined by the SPF algorithm
15. Which of the following are disadvantages of link-state routing? (Choose three.)
***Link-state protocols require careful network design.
Link-state protocols are prone to routing loops.
Link-state hello updates can cause broadcast flooding.
***Link-state protocols place significant demands on router processors and memory resources.
***Link-state protocols require a knowledgeable network administrator.
Link-state protocols do not support Variable Length Subnet Masking.
16. What are the benefits of the hierarchical design approach that is used in large OSPF networks? (Choose three.)
***reduction of routing overhead
increased routing overhead
***faster convergence
slower convergence
distribution of network instability to all areas of the network
***isolation of network instability to one area of the network
17. A network administrator has configured a default route on Router_A but it is not being shared with adjacent Router_B and the other routers in the OSPF area. Which command will save the administrator the time and trouble of configuring this default route on Router_B and all of the other routers in the OSPF area?
Router_A(config-router)# ospf redistribute default-route
Router_B(config-router)# ospf redistribute default-route
***Router_A(config-router)# default-information originate
Router_B(config-router)# default-information originate
Router_A(config-router)# ip ospf update-default
Router_B(config-router)# ip ospf update-default
18. What does OSPF use to calculate the cost to a destination network?
***bandwidth
bandwidth and hop count
bandwidth and reliability
bandwidth, load, and reliablity
19. What will be the result of the DR and BDR elections for this single area OSPF network? (Choose three.)
HQ will be DR for 10.4.0.0/16.
***Router A will be DR for 10.4.0.0/16.
***HQ will be BDR for 10.4.0.0/16.
Router A will be DR for 10.5.0.0/16.
***Remote will be DR for 10.5.0.0/16.
Remote will be BDR for 10.5.0.0/16.
20. The routers in the diagram are configured as shown. The loopback interface on router R1 is labeled as lo0. All OSPF priorities are set to the default except for Ethernet0 of router R2, which has an OSPF priority of 2. What will be the result of the OSPF DR/BDR elections on the 192.1.1.0 network? (Choose two.)
R1 will be the DR
R1 will be the BDR
***R2 will be the DR
R2 will be the BDR
R3 will be the DR
***R3 will be the BDR
www.inafridge.com – 2006