CCNA 3 v7 Modules 1 – 2: OSPF Concepts and Configuration Flashcards
What is a function of OSPF hello packets?
to send specifically requested link-state records
to discover neighbors and build adjacencies between them
to ensure database synchronization between routers
to request specific link-state records from neighbor routers
to discover neighbors and build adjacencies between them
Which OSPF packet contains the different types of link-state advertisements?
hello
DBD
LSR
LSU
LSAck
LSU
Which three statements describe features of the OSPF topology table? (Choose three.)
It is a link-state database that represents the network topology.
Its contents are the result of running the SPF algorithm.
When converged, all routers in an area have identical topology tables.
The topology table contains feasible successor routes.
The table can be viewed via the show ip ospf database command.
After convergence, the table only contains the lowest cost route entries for all known networks.
It is a link-state database that represents the network topology.
When converged, all routers in an area have identical topology tables.
The table can be viewed via the show ip ospf database command.
What does an OSPF area contain?
routers that share the same router ID
routers whose SPF trees are identical
routers that have the same link-state information in their LSDBs
routers that share the same process ID
routers that have the same link-state information in their LSDBs
What is used to facilitate hierarchical routing in OSPF?
the use of multiple areas
frequent SPF calculations
autosummarization
the election of designated routers
the use of multiple areas
Which OSPF data structure is identical on all OSPF routers that share the same area?
forwarding database
link-state database
adjacency database
routing table
link-state database
Which step does an OSPF-enabled router take immediately after establishing an adjacency with another router?
builds the topology table
exchanges link-state advertisements
chooses the best path
executes the SPF algorithm
exchanges link-state advertisements
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 not change from the default value.
The dead interval will now be 30 seconds.
The dead interval will now be 60 seconds.
The dead interval will now be 15 seconds.
The dead interval will now be 60 seconds.
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 R1 dead timer expires between hello packets from R2.
The hello timer on R2 expires every ten seconds.
The neighbor adjacency has formed.
The R1 dead timer expires between hello packets from R2.
To establish a neighbor adjacency two OSPF routers will exchange hello packets. Which two values in the hello packets must match on both routers? (Choose two.)
dead interval
router priority
list of neighbors
router ID
hello interval
dead interval
hello interval
What is the default router priority value for all Cisco OSPF routers?
0
1
10
255
1
Which type of OSPFv2 packet contains an abbreviated list of the LSDB of a sending router and is used by receiving routers to check against the local LSDB?
database description
link-state update
link-state request
link-state acknowledgment
database description
In an OSPF network when are DR and BDR elections required?
when the two adjacent neighbors are interconnected over a point-to-point link
when all the routers in an OSPF area cannot form adjacencies
when the routers are interconnected over a common Ethernet network
when the two adjacent neighbors are in two different networks
when the routers are interconnected over a common Ethernet network
When an OSPF network is converged and no network topology change has been detected by a router, how often will LSU packets be sent to neighboring routers?
every 5 minutes
every 10 minutes
every 30 minutes
every 60 minutes
every 30 minutes
What will an OSPF router prefer to use first as a router ID?
a loopback interface that is configured with the highest IP address on the router
any IP address that is configured using the router-id command
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
any IP address that is configured using the router-id command
What are the two purposes of an OSPF router ID? (Choose two.)
to uniquely identify the router within the OSPF domain
to facilitate router participation in the election of the designated router
to enable the SPF algorithm to determine the lowest cost path to remote networks
to facilitate the establishment of network convergence
to facilitate the transition of the OSPF neighbor state to Full
to uniquely identify the router within the OSPF domain
to facilitate router participation in the election of the designated router
Refer to the exhibit. If no router ID was manually configured, what would router Branch1 use as its OSPF router ID?
10.0.0.1
10.1.0.1
192.168.1.100
209.165.201.1
192.168.1.100
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 OSPF process ID on R1
the cost of the link to R1
the autonomous system number to which R1 belongs
the administrative distance that is manually assigned to R1
the area number where R1 is located
the OSPF process ID on R1
An OSPF router has three directly connected networks; 172.16.0.0/16, 172.16.1.0/16, and 172.16.2.0/16. Which OSPF network command would advertise only the 172.16.1.0 network to neighbors?
router(config-router)# network 172.16.1.0 0.0.255.255 area 0
router(config-router)# network 172.16.0.0 0.0.15.255 area 0
router(config-router)# network 172.16.1.0 255.255.255.0 area 0
router(config-router)# network 172.16.1.0 0.0.0.0 area 0
router(config-router)# network 172.16.1.0 255.255.255.0 area 0
Refer to the exhibit. Which three statements describe the results of the OSPF election process of the topology that is shown in the exhibit? (Choose three.)
R3 will be elected BDR.
The R4 FastEthernet 0/0 priority is 128.
The R4 router ID is 172.16.1.1.
R1 will be elected BDR.
The router ID on R2 is the loopback interface.
R2 will be elected DR.
R3 will be elected BDR.
The R4 router ID is 172.16.1.1.
R2 will be elected DR.
Refer to the exhibit. If the switch reboots and all routers have to re-establish OSPF adjacencies, which routers will become the new DR and BDR?
Router R4 will become the DR and router R1 will become the BDR.
Router R2 will become the DR and router R3 will become the BDR.
Router R1 will become the DR and router R2 will become the BDR.
Router R4 will become the DR and router R3 will become the BDR.
Router R4 will become the DR and router R1 will become the BDR.
By default, what is the OSPF cost for any link with a bandwidth of 100 Mb/s or greater?
100000000
10000
1
100
1