Friday, April 29, 2016

CCNAv2 Chapter 8 Quiz Answers (100%)

Greetings, welcome to Seeseenayy.
Below is the Chapter 8 Quiz for CCNA 2, hand-crafted by yours truly. 
I included the tutorial/explanations from the quiz page to help describe each response. Honestly, most answer pages don't ever have a tutorial section-- this is the least I could do.


Question 1
Which two statements are correct about the OSPF passive-interface command? (Choose two.) 
The OSPF network will benefit from more efficient use of bandwidth and resources. 
The router will not advertise the network of the passive interface to its neighbors.
OSPF link-state information is still sent and received through the passive interface. 
The router will not establish any OSPF neighbor relationships with routers on that link.

Question Explanation:
Refer to curriculum topic: 8.2.2 
>>The passive-interface router configuration mode command prevents routing messages from being transmitted through a router interface but it will still allow that network to be advertised to other routers through other participating interfaces. Stopping the unnecessary forwarding of routing protocol messages through a LAN interface saves bandwidth and provides more efficient use of resources on LAN devices.

Question 2
Which OSPF wildcard mask would be appropriate to use for the given network prefix?
/13 and 0.7.255.255

Question Explanation:
Refer to curriculum topic: 8.2.2 To calculate wildcard masks, follow these steps: 
1. Change the subnet mask into dotted-decimal format. 
2. Subtract the resulting mask from 255.255.255.255. 
3. The result is the wildcard mask. 
Example: A mask of /18 equals 255.255.192.0. A mask of 255.255.192.0 subtracted from 255.255.255.255 yields a wildcard mask of 0.0.63.255.

Question 3
Match each OSPF packet type to how it is used by a router. (Not all options are used.)
In Order:
advertise new information
compare local topology to that sent by another router
establish and maintain adjacencies
query another router for additional information

Question Explanation: 
Refer to curriculum topic: 8.1.2


Question 4
Which statement is correct about multiarea OSPF?
OSPF can consolidate a fragmented OSPF area into one large area
All routers are in one area called the backbone area (area 0).
Arranging routers into areas partitions a large autonomous system in order to lighten the load on routers.
OSPF multiarea increases the frequency of SPF calculation.

Question Explanation: 
Refer to curriculum topic: 8.1.1 
A company with one large autonomous system or AS can be divided into smaller areas. When this occurs and the OSPF routing protocol is implemented, the design is called multi-area OSPF. Multi-area OSPF decreases the frequency of the SPF calculation, thus lightening the load on the router. In a single area OSPF design, all the routers are located in area 0 or the backbone area.

Question 5
Fill in the blank. The wildcard mask that is used to advertise exactly the network 192.168.160.0 with subnet mask 255.255.240.0 is what?
0.0.15.255

Question Explanation: 
Refer to curriculum topic: 8.2.2 
The easiest method for calculating a wildcard mask is to subtract the network subnet mask from 255.255.255.255. In this case we have 255.255.255.255 - 255.255.240.0.


Question 6
Which statement describes a difference or similarity between OSPFv2 and OSPFv3?
OSPFv2 requires the DR/BDR election to occur on multiaccess networks only, whereas OSPv3 requires DR/BDR elections for all network types.
Both OSPFv2 and OSPFv3 use the router configuration network command to advertise networks.
Both OSPFv2 and OSPFv3 use multicast destination addresses for link-state packets.
OSPFv2 uses a 32 bit router ID and OSPFv3 uses a 128 bit router ID.

Question Explanation: 
Refer to curriculum topic: 8.3.1 
OSPFv2 uses the router configuration network command to advertise networks. OSPFv3 uses the ipv6 ospf process-id area area-id interface configuration command. Both OSPFv2 and OSPFv3 use a 32 bit router ID. Both OSPFv2 and OSPFv3 require the DR/BDR election to occur on multiaccess networks. Neither protocol requires a DR/BDR election for point-to-point networks.


Question 7
At which OSPF state are neighbor routers converged and able to exchange routing updates?
Two-Way
ExStart
Exchange
Full

Question Explanation: 
Refer to curriculum topic: 8.1.3 
OSPF neighbors that reach the Full state are converged and can exchange routing information.

Question 8
Fill in the blank. Do not use abbreviations. The command "clear ip ospf _____" forces a router with a new or changed router ID to form new adjacencies.
process

Question Explanation: 
Refer to curriculum topic: 8.2.1 
An active OSPF router will not allow the router ID to be changed until it is reloaded or the OSPF process is cleared. Clearing the current process forces the router to renegotiate adjacencies and advertise its new information.

Question 9
A network technician issues the following commands when configuring a router: R1(config)# router ospf 11 
R1(config-router)# network 10.10.10.0 0.0.0.255 area 0 
What does the number 11 represent?
the autonomous system number to which R1 belongs 
the area number where R1 is located 
the cost of the link to R1 
the OSPF process ID on R1 
the administrative distance that is manually assigned to R1

Question 10
A network administrator configures a loopback interface as the OSPF router ID with the IP address of 192.168.1.1/30. What could be the consequence of using this 30-bit mask for the loopback interface?
Older routers do not recognize the router-id command.
The interface is not enabled for OSPF.
OSPF routers must also be configured with a router priority value.
This loopback interface may be advertised as a reachable network.

Question Explanation: 
Refer to curriculum topic: 8.2.1 
A loopback interface used as an OSPF router ID normally uses a 32-bit mask that creates a host route. This route is not advertised as a route to other routers unless a network statement including this interface is added.

Question 11

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Media consists of a network topology showing three connected routers. Router R1 is connected to Router R2 horizontally by a red solid line in the form of a lightning flash. Shown above the connecting line is 192.168.3.0/30, and below the line is 64 kb/s. Router R2 is connected to router R3 by a vertical solid straight red line. Next to this connecting line on one side is 172.16.2.0/30, and on the other side of the line is 100 Mb/s. Router R3 is connected to a cloud icon with a horizontal solid straight red line. Beneath this connecting line is 172.16.1.0/24.

Fill in the blank. 
Refer to the exhibit. With the default metric settings, the OSPF cost for R1 to reach the network 172.16.1.0 is ____?
1564


Question Explanation: 
Refer to curriculum topic: 8.2.3 
The OSPF cost metric is the accumulated value from R1 to network 172.16.1.0. The cost for the first link is 100,000,000/64,000 (1562). The cost for the second link is 100,000,000/100,000,000 (1). The cost for the third link is 100,000,000/100,000,000 (1). The OSPF cost metric from R1 to 172.16.1.0 is therefore 1564.


Question 12
The OSPF hello timer has been set to 15 seconds on a router in a point-to-point network. By default, what is the dead interval on this router?
15 Seconds
30 Seconds
45 Seconds
60 Seconds

Question Explanation: 
Refer to curriculum topic: 8.1.2 
By default, the dead interval is calculated as 4 times the hello interval.

Question 13
What are three entries that are displayed by the show ip ospf neighbor command? (Choose three.)
the route metric and neighbor next hop address 
the router ID of the neighboring routers 
the OSPF state of each interface 
the OSPF process ID used to establish the adjacency 
the OSPF area number shared by the neighbor routers 
the IP address of the neighbor router interface to which this router is directly connected

Question Explanation: 
Refer to curriculum topic: 8.2.4 
The route metric and neighbor next hop address are routing table entries that are displayed by the show ip route command. The show ip ospf neighbor command does not display the OSPF process ID or the OSPF area number.

Question 14
What will an OSPF router prefer to use first as a router ID?
any IP address that is configured using the router-id command 
a loopback interface that is configured with the highest IP address on the router 
the highest active interface IP that is configured on the router
the highest active interface that participates in the routing process because of a specifically configured network statement

Question Explanation: 
Refer to curriculum topic: 8.2.1 
The first preference for an OSPF router ID is an explicitly configured 32-bit address. This address is not included in the routing table and is not defined by the network command. If a router ID that is configured through the router-id command is not available, OSPF routers next use the highest IP address available on a loopback interface, as loopbacks used as router IDs are also not routable addresses. Lacking either of these alternatives, an OSPF router will use the highest IP address from its active physical interfaces.




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