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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