CCNA - OSPF Quiz Questions And Answers

1. What is the default administrative distance of OSPF?

120

100

90

110

The default administrative distance of OSPF is 110. Administrative distance is a measure of the trustworthiness of a routing protocol. It is used by routers to determine which route to choose when there are multiple routes to the same destination. A lower administrative distance indicates a more trustworthy protocol, and OSPF has a default administrative distance of 110. This means that if there are multiple routes available, OSPF will be preferred over protocols with a higher administrative distance, such as RIP (120) or EIGRP (90).

Explanation

The default administrative distance of OSPF is 110. Administrative distance is a measure of the trustworthiness of a routing protocol. It is used by routers to determine which route to choose when there are multiple routes to the same destination. A lower administrative distance indicates a more trustworthy protocol, and OSPF has a default administrative distance of 110. This means that if there are multiple routes available, OSPF will be preferred over protocols with a higher administrative distance, such as RIP (120) or EIGRP (90).

2. A network administrator is trying to add a new router to 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?

The process id is configured improperly.

The OSPF area is configured improperly.

The network wildcard mask is configured improperly.

The network number is configured improperly.

The AS is configured improperly.

The network subnet mask is configured improperly.

The network wildcard mask is configured improperly. In OSPF, the wildcard mask is used to determine which IP addresses are included in the OSPF network. It is used in conjunction with the network number to define the network. If the wildcard mask is configured improperly, it may not match the actual network addresses attached to the new router, causing them to not appear in the routing tables of the other OSPF routers.

Explanation

The network wildcard mask is configured improperly. In OSPF, the wildcard mask is used to determine which IP addresses are included in the OSPF network. It is used in conjunction with the network number to define the network. If the wildcard mask is configured improperly, it may not match the actual network addresses attached to the new router, causing them to not appear in the routing tables of the other OSPF routers.

3. 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?

10.1.1.2

10.154.154.1

172.16.5.1

192.168.5.316

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

Explanation

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

4. 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)

Router(config)#router ospf 1

Router(config)#router ospf 0

Router(config)#router ospf area 0

Router(config-router)#network 192.168.16.0 0.0.0.255 area 0

Router(config-router)#network 192.168.16.0 0.0.0.255 0

Router(config-router)#network 192.168.16.0 255.255.255.0 area 0

The correct answer is "Router(config)#router ospf 1" and "Router(config-router)#network 192.168.16.0 0.0.0.255 area 0".

The first command "Router(config)#router ospf 1" is used to enable OSPF routing protocol on the router and assign it a process ID of 1.

The second command "Router(config-router)#network 192.168.16.0 0.0.0.255 area 0" is used to add the network 192.168.16.0/24 to OSPF area 0. The network command specifies the network address and wildcard mask, and the area parameter specifies the OSPF area to which the network belongs.

Explanation

The correct answer is "Router(config)#router ospf 1" and "Router(config-router)#network 192.168.16.0 0.0.0.255 area 0".

The first command "Router(config)#router ospf 1" is used to enable OSPF routing protocol on the router and assign it a process ID of 1.

The second command "Router(config-router)#network 192.168.16.0 0.0.0.255 area 0" is used to add the network 192.168.16.0/24 to OSPF area 0. The network command specifies the network address and wildcard mask, and the area parameter specifies the OSPF area to which the network belongs.

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

16

2

Unlimited

4

The default maximum number of equal-cost paths that can be placed into the routing of a Cisco OSPF router is 4. This means that the router can have up to 4 different paths with the same cost to reach a destination network. This allows for load balancing and redundancy in the network, as the router can distribute traffic across multiple paths.

Explanation

The default maximum number of equal-cost paths that can be placed into the routing of a Cisco OSPF router is 4. This means that the router can have up to 4 different paths with the same cost to reach a destination network. This allows for load balancing and redundancy in the network, as the router can distribute traffic across multiple paths.

6.

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)

FastEthernet0/0

FastEthernet0/1

Serial0/0

Serial0/1.102

Serial0/1.103

Serial0/1.104

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.

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.

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7. 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

All OSPF routers in an area must have the same process ID.

Only one process number can be used on the same router.

Different process identifiers can be used to run multiple OSPF processes.

The process number can be any number from 1 to 65,535.

Hello packets are sent to each neighbor to determine the processor identifier.

The process identifier used in the command to configure OSPF on a router can be any number from 1 to 65,535. This allows for flexibility in assigning unique identifiers to different OSPF processes running on the same router. Additionally, different process identifiers can be used to run multiple OSPF processes, enabling the router to participate in multiple OSPF instances simultaneously.

Explanation

The process identifier used in the command to configure OSPF on a router can be any number from 1 to 65,535. This allows for flexibility in assigning unique identifiers to different OSPF processes running on the same router. Additionally, different process identifiers can be used to run multiple OSPF processes, enabling the router to participate in multiple OSPF instances simultaneously.

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

To confine network instability to single areas of the network.

To reduce the complexity of router configuration

To speed up convergence

To lower costs by replacing routers with distribution layer switches

To decrease latency by increasing bandwidth

To reduce routing overhead

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).

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).

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9. Which statements describe the routing protocol OSPF? (Choose three

It supports VLSM.

It is used to route between autonomous systems.

It confines network instability to one area of the network.

It increases routing overhead on the network.

It allows extensive control of routing updates.

It is simpler to configure than RIPv2.

OSPF supports VLSM, which stands for Variable Length Subnet Masking. This allows for more efficient allocation of IP addresses by allowing the use of different subnet mask lengths within a single network. OSPF also confines network instability to one area of the network, meaning that if there is a problem or change in one area, it does not affect the entire network. Additionally, OSPF allows extensive control of routing updates, giving administrators more flexibility and control over how routing information is exchanged between routers.

Explanation

OSPF supports VLSM, which stands for Variable Length Subnet Masking. This allows for more efficient allocation of IP addresses by allowing the use of different subnet mask lengths within a single network. OSPF also confines network instability to one area of the network, meaning that if there is a problem or change in one area, it does not affect the entire network. Additionally, OSPF allows extensive control of routing updates, giving administrators more flexibility and control over how routing information is exchanged between routers.

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

Provides a common view of the entire topology

Exchanges routing tables with neighbors

Calculates the shortest path

Utilizes event-triggered updates

Utilizes frequent periodic updates

A link-state routing protocol is characterized by three main features. Firstly, it provides a common view of the entire topology, meaning that all routers in the network have access to the same information about the network's layout. Secondly, it calculates the shortest path, allowing routers to determine the most efficient route for forwarding packets. Lastly, it utilizes event-triggered updates, which means that routing updates are only sent when there is a change in the network, reducing unnecessary traffic.

Explanation

A link-state routing protocol is characterized by three main features. Firstly, it provides a common view of the entire topology, meaning that all routers in the network have access to the same information about the network's layout. Secondly, it calculates the shortest path, allowing routers to determine the most efficient route for forwarding packets. Lastly, it utilizes event-triggered updates, which means that routing updates are only sent when there is a change in the network, reducing unnecessary traffic.

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