martes, 4 de agosto de 2015

CCNA 3 Cisco v5.0 Chapter 5 - Answers

1. A network administrator has just changed the router ID on a router that is working in an OSPFv2 environment. What should the administrator do to reset the adjacencies and use the new router ID?

Configure the network statements.
Change the interface priority.
Change the OSPFv2 process ID.
Issue the clear ip ospf process privileged mode command.

2. Which two pieces of information are used by the OSPF MD5 algorithm to generate a signature? (Choose two.)

interface IP address
OSPF router ID
OSPF message
secret key 
router hostname

3. When checking a routing table, a network technician notices the following entry:

O*E2 [110/1] via, 00:20:22, Serial0/0/0

What information can be gathered from this output?

This route is a propagated default route.
The route is located two hops away.
The metric for this route is 110.
The edge of the OSPF area 0 is the interface that is addressed

4. Which command will a network engineer issue to verify the configured hello and dead timer intervals on a point-to-point WAN link between two routers that are running OSPFv2?

show ip ospf interface fastethernet 0/1
show ip ospf interface serial 0/0/0 
show ip ospf neighbor
show ipv6 ospf interface serial 0/0/0

5. A network engineer has manually configured the hello interval to 15 seconds on an interface of a router that is running OSPFv2. By default, how will the dead interval on the interface be affected?

The dead interval will now be 15 seconds.
The dead interval will now be 60 seconds. 
The dead interval will now be 30 seconds.
The dead interval will not change from the default value.

6. When OSPFv2 neighbors are establishing adjacencies, in which state do they elect a DR and BDR router?

Exchange state
Two-Way state
Loading state
Init state


Refer to the exhibit. A network administrator has configured the OSPF timers to the values that are shown in the graphic. What is the result of having those manually configured timers?

R1 automatically adjusts its own timers to match the R2 timers.
The neighbor adjacency has formed.
The hello timer on R2 expires every ten seconds.
The R1 dead timer expires between hello packets from R2.


Refer to the exhibit. Fill in the blank. Do not use abbreviations.

The command show ipv6 route can be issued on router R2 to verify the propagation of a static default route from R1 to R2.

9. A network engineer is troubleshooting convergence and adjacency issues in an OSPFv2 network and has noted that some expected network route entries are not displayed in the routing table. Which two commands will provide additional information about the state of router adjacencies, timer intervals, and the area ID? (Choose two.)

show ip protocols
show ip route ospf
show running-configuration
show ip ospf interface 
show ip ospf neighbor


Refer to the exhibit. What kind of OSPF authentication has been configured on this interface?

plain text


12. Which command is used to verify that OSPF is enabled and also provides a list of the networks that are being advertised by the network?

show ip interface brief
show ip route ospf
show ip protocols 
show ip ospf interface


Refer to the exhibit. R1 and R2 are connected to the same LAN segment and are configured to run OSPFv3. They are not forming a neighbor adjacency. What is the cause of the problem?

The IPv6 addresses of R1 and R2 are not in the same subnet.
The OSPFv3 process IDs of R1 and R2 are different.
The timer intervals of R1 and R2 do not match. 
The priority value of both R1 and R2 is 1.


Refer to the exhibit. Four routers are connected to an Ethernet LAN segment and are configured to run OSPFv3. However, none of the routers are receiving routing updates. What is the cause of the problem?

All of the routers have an OSPFv3 interface priority of 0. 
The network type has been set to BROADCAST instead of NBMA.
The routers are using IPv6 link local addresses to communicate.
The routers are using IPv4 addresses for router IDs.


Refer to the exhibit. What three conclusions can be drawn from the displayed output? (Choose three.)

This interface is using the default priority.
The router ID values were not the criteria used to select the DR and the BDR.
The DR can be reached through the GigabitEthernet 0/0 interface. 
The router ID on the DR router is
The BDR has three neighbors.
There have been 9 seconds since the last hello packet sent.

16. A network engineer is troubleshooting OSPFv2 routing issues on two connected routers. Which two requirements to form an adjacency need to be verified? (Choose two.)

Verify that one of the routers is the DR or BDR and the other router a DRother.
Verify that one of the interfaces that connects the two routers is active and the other passive.
Verify that the interfaces that connect the two routers are in the same area. 
Verify that both routers are using the same OSPFv2 process ID.
Verify that the interfaces that connect the two routers are in the same subnet.


18. Why do OSPF serial interfaces usually require manual bandwidth configuration?

OSPF uses the bandwidth value to compute routes for its routing table. 
All serial interfaces default to a value of 1.544 Mb/s.
Bandwidth value affects the actual speed of the link.
Each side of an OSPF serial link should be configured with a unique value


Refer to the exhibit. These two routers are configured to run OSPFv3 but they are not forming a neighbor adjacency. What is the cause of the problem?

The routers have both been elected as the DR.
The routers do not have global IPv6 addresses that are configured on the Fa0/0 interfaces.
The routers are configured with the same router ID. 
The routers have the same priority.


Refer to the exhibit. An administrator is trying to configure R1 to run OSPFv3 but the neighbor adjacency is not forming with the router connected to Fa0/0. What is the cause of the problem?

A link-local address has not been configured on interface FastEthernet0/0.
No router ID has been configured. 
FastEthernet0/0 has been configured as a passive interface.
The OSPF process ID and area values are backwards in the interface configuration.

21. A network engineer suspects that OSPFv3 routers are not forming neighbor adjacencies because there are interface timer mismatches. Which two commands can be issued on the interface of each OSFPv3 router to resolve all timer mismatches? (Choose two.)

ip ospf hello-interval 10
no ipv6 ospf hello-interval
no ipv6 router ospf 10
no ipv6 ospf dead-interval
ip ospf dead-interval 40
no ipv6 ospf cost 10

22. Fill in the blank. Do not use abbreviations.

When IPv4 and OSPFv2 are being used, the command show ip ospf neighbor is used to verify that a router has formed an adjacency with its neighboring routers.

23. Why is MD5 authentication more secure than simple authentication for OSPF updates?

MD5 employs IPsec to keep the updates from being intercepted.
MD5 does not send the password to the neighbor router. 
MD5 uses both a username and a password to authenticate the neighbor.
MD5 requires passwords that are at least 8 characters long.

24. A network engineer is troubleshooting an OSPFv2 network and discovers that two routers connected by a point-to-point WAN serial link are not establishing an adjacency. The OSPF routing process, network commands and area ID are all confirmed as correct, and the interfaces are not passive. Testing shows that the cabling is correct, that the link is up, and pings between the interfaces are successful. What is most likely the problem?

The OSPFv2 process IDs on each router do not match.
A clock rate has not been set on the DCE interface of the serial link.
The subnet masks on the two connected serial interfaces do not match. 
A DR election has not taken place.

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Espero haber ayudado en algo. Hasta la próxima oportunidad!

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