New CCNA – OSPF Questions

Note: If you are not sure about OSPF, please read our OSPF Tutorial.

Question 1

Which characteristics are representative of a link-state routing protocol? (Choose three)

A. provides common view of entire topology
B. exchanges routing tables with neighbors
C. calculates shortest path
D. utilizes event-triggered updates
E. utilizes frequent periodic updates

 

Answer: A C D

Question 2

Which statements describe the routing protocol OSPF? (Choose three)

A. It supports VLSM.
B. It is used to route between autonomous systems.
C. It confines network instability to one area of the network.
D. It increases routing overhead on the network.
E. It allows extensive control of routing updates
F. It is simpler to configure than RIPv2.

 

Answer: A C E

Explanation

Answer A and C are obviously correct. For answer E, it allows extensive control of routing updates via Link-State Advertisement (LSA). Administrators can filter these LSAs to meet their requirements easily.

Question 3

A network administrator is trying to add a new router into an established OSPF network. The networks attached to the new router do not appear in the routing tables of the other OSPF routers. Given the information in the partial configuration shown below, what configuration error is causing this problem?

Router(config)# router ospf 1 Router(config-router)# network 10.0.0.0 255.0.0.0 area 0

A. The process id is configured improperly.
B. The OSPF area is configured improperly.
C. The network wildcard mask is configured improperly.
D. The network number is configured improperly.
E. The AS is configured improperly.
F. The network subnet mask is configured improperly.

 

Answer: C

Question 4

A network associate has configured OSPF with the command:
City(config-router)# network 192.168.12.64 0.0.0.63 area 0

After completing the configuration, the associate discovers that not all the interfaces are participating in OSPF.
Which three of the interfaces shown in the exhibit will participate in OSPF according to this configuration statement? (Choose three)

A. FastEthernet0/0
B. FastEthernet0/1
C. Serial0/0
D. Serial0/1.102
E. Serial0/1.103
F. Serial0/1.104

 

Answer: B C D

Explanation

The “network 192.168.12.64 0.0.0.63″ equals to network 192.168.12.64/26. This network has:
+ Increment: 64 (/26= 1111 1111.1111 1111.1111 1111.1100 0000)
+ Network address: 192.168.12.64
+ Broadcast address: 192.168.12.127
Therefore all interface in the range of this network will join OSPF -> B C D are correct.

Question 5

What is the default maximum number of equal-cost paths that can be placed into the routing of a Cisco OSPF router?

A. 16
B. 2
C. unlimited
D. 4

 

Answer: D

Explanation

The default number of equal-cost paths that can be placed into the routing of a Cisco OSPF router is 4. We can change this default value by using “maximum-paths” command:

Router(config-router)#maximum-paths 2

Note: Cisco routers support up to 6 equal-cost paths

Question 6

Which two statements describe the process identifier that is used in the command to configure OSPF on a router? (Choose two)

Router(config)# router ospf 1
A. All OSPF routers in an area must have the same process ID.
B. Only one process number can be used on the same router.
C. Different process identifiers can be used to run multiple OSPF processes
D. The process number can be any number from 1 to 65,535.
E. Hello packets are sent to each neighbor to determine the processor identifier.

 

Answer: C D

Question 7

Why do large OSPF networks use a hierarchical design? (Choose three)

A. to confine network instability to single areas of the network.
B. to reduce the complexity of router configuration
C. to speed up convergence
D. to lower costs by replacing routers with distribution layer switches
E. to decrease latency by increasing bandwidth
F. to reduce routing overhead

 

Answer: A C F

Explanation

Hierarchical design of OSPF (basically means that you can separate the larger internetwork into smaller internetworks called areas) helps us create a network with all features listed above (decrease routing overhead, speed up convergence, confine network instability to single areas of the network).

Question 8

Which commands are required to properly configure a router to run OSPF and to add network 192.168.16.0/24 to OSPF area 0? (choose two)

A. Router(config)#router ospf 1
B. Router(config)#router ospf 0
C. Router(config)#router ospf area 0
D. Router(config-router)#network 192.168.16.0 0.0.0.255 area 0
E. Router(config-router)#network 192.168.16.0 0.0.0.255 0
F. Router(config-router)#network 192.168.16.0 255.255.255.0 area 0

 

Answer: A D

Explanation

In the router ospf command, the ranges from 1 to 65535 so o is an invalid number -> A is correct but B is not correct.

Question 9

Refer to the exhibit. Given the output for this command, if the router ID has not been manually set, what router ID will OSPF use for this RouterD?

RouterD# show ip interface brief

 

A. 10.1.1.2
B. 10.154.154.1
C. 172.16.5.1
D. 192.168.5.316

 

Answer: C

Explanation

The highest IP address of all loopback interfaces will be chosen -> Loopback 0 will be chosen as the router ID.

Question 10

What is the default administrative distance of OSPF?
A. 120
B. 100
C. 90
D. 110

 

Answer: D