B mod 1/2 single area OSPFv2 concepts/configuration
What is the order of packet types used by an OSPF router to establish convergence
Hello, DBD, LSR, LSU, LSAck
Refer to the exhibit. Suppose that routers B, C, and D have a default priority, and router A has a priority 0. Which conclusion can be drawn from the DR/BDR election process
If the DR fails, the new DR will be router B.
Which three statements describe features of the OSPF topology table? (Choose three.)
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 is a feature of the OSPF routing protocol
It scales well in both small and large networks
In an OSPFv2 configuration, what is the effect of entering the command network 192.168.1.1 0.0.0.0 area 0
It tells the router which interface to turn on for the OSPF routing process.
Which OPSF packet contains the different types of link-state advertisements?
LSU
A network technician issues the following commands when configuring a router
OSPF process ID on R1
A router is participating in an OSPFv2 domain. What will always happen if the dead interval expires before the router receives a hello packet from an adjacent DROTHER OSPF router?
OSPF will remove that neighbor from the router link-state database.
Refer to the exhibit. On which router or routers would a default route be statically configured in a corporate environment that uses single area OSPF as the routing protocol
R0-A
Refer to the exhibit. Which command did an administrator issue to produce this output
R1# show ip ospf interface serial0/0/1
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?
The R1 dead timer expires between hello packets from R2.
What happens immediately after two OSPF routers have exchanged hello packets and have formed a neighbor adjacency
They exchange abbreviated lists of their LSDBs.
What is a benefit of multiarea OSPF routing
Topology changes in one area do not cause SPF recalculations in other areas.
What is used to create the OSPF neighbor table?
adjacency database
What function is performed by the OSPF designated router
dissemination of LSAs
What type of address is 64.101.198.197
public
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 serial 0/0/0
What is a function of OSPF hello packets?
to discover neighbors and build adjacencies between them
In an OSPF network when are DR and BDR elections required
when the routers are interconnected over a common Ethernet network
An administrator is configuring single-area OSPF on a router. One of the networks that must be advertised is 64.102.0.0 255.255.255.128. What wildcard mask would the administrator use in the OSPF network statement
0.0.0.127
An administrator is configuring single-area OSPF on a router. One of the networks that must be advertised is 192.168.181.0 255.255.254.0. What wildcard mask would the administrator use in the OSPF network statement
0.0.1.255
An administrator is configuring single-area OSPF on a router. One of the networks that must be advertised is 192.168.223.0 255.255.254.0. What wildcard mask would the administrator use in the OSPF network statement
0.0.1.255
An administrator is configuring single-area OSPF on a router. One of the networks that must be advertised is 128.107.0.0 255.255.252.0. What wildcard mask would the administrator use in the OSPF network statement
0.0.3.255
An administrator is configuring single-area OSPF on a router. One of the networks that must be advertised is 198.19.0.0 255.255.252.0. What wildcard mask would the administrator use in the OSPF network statement
0.0.3.255
An administrator is configuring single-area OSPF on a router. One of the networks that must be advertised is 128.107.0.0 255.255.255.192. What wildcard mask would the administrator use in the OSPF network statement
0.0063
By default, what is the OSPF cost for any link with a bandwidth of 100 Mb/s or greater
1
What is the default router priority value for all Cisco OSPF routers
1
Refer to the exhibit. If no router ID was manually configured, what would router Branch1 use as its OSPF router ID
192.168.1.100
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?
60 seconds
Refer to the exhibit. What is the OSPF cost to reach the router A LAN 172.16.1.0/24 from B
65
Which statement is correct about multiarea OSPF?
Arranging routers into areas partitions a large autonomous system in order to lighten the load on routers.
What is the recommended Cisco best practice for configuring an OSPF-enabled router so that each router can be easily identified when troubleshooting routing issues
Configure a value using the router-id command.
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 30 minutes
Which three OSPF states are involved when two routers are forming an adjacency? (Choose three.)
Init Two-way Down
Refer to the exhibit. A network administrator has configured OSPFv2 on the two Cisco routers but PC1 is unable to connect to PC2. What is the most likely problem
Interface Fa0/0 has not been activated for OSPFv2 on router R2.
What is the format of the router ID on an OSPF-enabled router
a 32-bit number formatted like an IPv4 address
Match the description to the term. (Not all options are used.)
adjacency database => This is where the details of the neighboring routers can be found. Shortest Path First => This is the algorithm used by OSPF. Single-area OSPF => All the routers are in the backbone area. - not scored - link-state database => This is where you can find the topology table. - not scored -
What will an OSPF router prefer to use first as a router ID?
any IP address that is configured using the router-id command
Which step in the link-state routing process is described by a router building a link-state database based on received LSAs
building the topology table
Which step in the link-state routing process is described by a router inserting best paths into the routing table?
choosing the best route
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
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 hello interval
Which step in the link-state routing process is described by a router sending Hello packets out all of the OSPF-enabled interfaces?
establishing neighbor adjacencies
Which step in the link-state routing process is described by a router flooding link-state and cost information about each directly connected link?
exchanging link-state advertisements
Which step in the link-state routing process is described by a router running an algorithm to determine the best path to each destination
executing the SPF algorithm
At which OSPF state are neighbor routers converged and able to exchange routing updates?
full
What indicates to a link-state router that a neighbor is unreachable
if the router no longer receives hello packets
What is identical on all OSPF routers within a single area
link-state database
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
What does an OSPF area contain?
routers that have the same link-state information in their LSDBs
What command would be used to determine if a routing protocol-initiated relationship had been made with an adjacent router
show ip ospf neighbor
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 protocols
What is the reason for a network engineer to alter the default reference bandwidth parameter when configuring OSPF
to more accurately reflect the cost of links greater than 100 Mb/s
What are two reasons for creating an OSPF network with multiple areas? (Choose two.)
to reduce SPF calculations to reduce use of memory and processor resources
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