OSPF Questions
Question 1
What characteristics do a link-state routing protocol have? (Choose three)
A. Each node has a common map of the whole topology
B. Each node advertises full routing table with other neighbors
C. Use shortest path algorithm
D. send updates periodically
E. send updates on changes only
Answer: A C E
Question 2
Which of the following statements are correct about OSPF? (Choose three)
A. It uses Dijkstra algorithm
B. It uses Diffusing Update (DUAL) algorithm
C. It supports VLSM
D. It uses bandwidth to calculate cost
E. It uses hop count to calculate cost
Answer: A C D
Question 3
A technician has configured a new router into OSPF domain with the following commands:
R1(config)#router ospf 100
R1(config-router)#network 192.168.1.0 255.255.255.0 area 0
But 192.168.1.0/24 network do not appear in the routing table of other OSPF routers. What caused this problem?
A. OSPF process number is mismatched
B. OSPF area number is mismatched
C. The wildcard mask is wrongly configured
D. The network is wrongly configured
E. The interface must be turned on
Answer: C
Question 4
Check the output shown below of TUT router with the “show ip interface brief” command.
A technician enter the following commands:
TUT_Router(config)#router ospf 1
TUT_Router(config-router)#network 10.10.15.64 0.0.0.63 area 0
Which interfaces will participate into OSPF process 1? (Choose three)
A. Fa1/0
B. Fa1/1
C. Serial1/0
D. Serial1/1.1
E. Serial1/1.2
F. Serial1/1.3
Answer: B C D
Explanation
The “network 10.10.15.64 0.0.0.63″ equals to network 10.10.15.64/26. This network has:
+ Increment: 64 (/26= 1111 1111.1111 1111.1111 1111.1100 0000)
+ Network address: 10.10.15.64
+ Broadcast address: 10.10.15.127
Therefore all interface in the range of this network will join OSPF -> B C D are correct.
Question 5
What is the maximum number of equal-cost paths to the same destination that OSPF can install in the IP routing table by default?
A. 2
B. 6
C. 4
D. 8
E. 16
Answer: C
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 of the following statements are correct about OSPF process identifier?
A. There is only one OSPF process identifier that can be configured on a router
B. Many OSPF process identifiers can be configured on a router. Each runs a separate OSPF process
C. The process identifier is advertised to other OSPF routers in hello packets
D. The range of OSPF process identifier is from 1 to 65,535
E. OSPF routers must run the same process number to form neighbor relationship
Answer: B D
Question 7
What are the advantages of hierarchical design in OSPF topologies? (Choose three)
A. mitigate the instability to one area when there is a change in the topology
B. increase the speed of convergence
C. increase the speed of transmission
D. areas help reduce routing overhead because of fewer packets need to be processed
E. decrease the number of routers need to be used
Answer: A B D
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 of the following commands should be used to advertise network 10.10.1.0/24 with OSPF? (Choose two)
A. router ospf 45
B. router ospf
C. router ip ospf
D. network 10.10.1.0/24 area 0
E. network 10.10.1.0 subnet-mask 255.255.255.0 area 0
F. network 10.10.1.0 0.0.0.255 area 0
Answer: A F
Explanation
In the router ospf command, the OSPF process ID ranges from 1 to 65535 -> A is correct
Question 9
Check the output below. Which IP will be chosen as the OSPF router ID if the router ID was not assigned manually?
A. 192.168.15.48
B. 210.110.15.121
C. 10.10.15.125
D. 10.10.15.129
Answer: D
Explanation
The highest IP address of all loopback interfaces will be chosen -> Loopback1 will be chosen as the router ID.
Question 10
A colleague wants to know about the default administrative distance of OSPF. What will you answer her?
A. 120
B. 110
C. 90
D. 20
E. 1
F. 10
Answer: B