1.4.2 Module Quiz – Single-Area OSPFv2 Concepts Answers
1. What is a function of OSPF hello packets?
- to discover neighbors and build adjacencies between them
- to ensure database synchronization between routers
- to send specifically requested link-state records
- to request specific link-state records from neighbor routers
2. Which OPSF packet contains the different types of link-state advertisements?
3. Which statements describe features of the OSPF topology table? (Choose three.)
- After convergence, the table only contains the lowest cost route entries for all known networks.
- The topology table contains feasible successor routes.
- The table can be viewed via the show ip ospf database command.
- Its contents are the result of running the SPF algorithm.
- It is a link-state database that represents the network topology.
- When converged, all routers in an area have identical topology tables.
4. What does an OSPF area contain?
- routers that share the same process ID
- routers that share the same router ID
- routers that have the same link-state information in their LSDBs
- routers whose SPF trees are identical
5. 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?
- A new dead interval timer of 4 times the hello interval will start.
- SPF will run and determine which neighbor router is “down”.
- OSPF will run a new DR/BDR election.
- OSPF will remove that neighbor from the router link-state database.
6. What is the order of packet types used by an OSPF router to establish convergence?
- LSAck, Hello, DBD, LSU, LSR
- LSU, LSAck, Hello, DBD, LSR
- Hello, DBD, LSR, LSU, LSAck
- Hello, LSAck, LSU, LSR, DBD
7. What is a feature of the OSPF routing protocol?
- OSPF authentication is configured in the same way on IPv4 and IPv6 networks.
- Routers can be grouped into autonomous systems to support a hierarchical system.
- It scales well in both small and large networks.
- The SPF algorithm chooses the best path based on 30-second updates.
8. What is used to create the OSPF neighbor table?
- link-state database
- forwarding database
- routing table
- adjacency database
9. What is identical on all OSPF routers within a single area?
- neighbor table
- routing table
- link-state database
- static routes
10. What function is performed by the OSPF designated router?
- summarizing routes between areas
- maintaining the link-state database
- redistribution of external routes into OSPF
- dissemination of LSAs
11. What are two reasons for creating an OSPF network with multiple areas? (Choose two.)
- to simplify configuration
- to ensure that an area is used to connect the network to the Internet
- to reduce use of memory and processor resources
- to reduce SPF calculations
- to provide areas in the network for routers that are not running OSPF
12. At which OSPF state are neighbor routers converged and able to exchange routing updates?
13. 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?
- 30 seconds
- 60 seconds
- 45 seconds
- 15 seconds
14. What happens immediately after two OSPF routers have exchanged hello packets and have formed a neighbor adjacency?
- They exchange abbreviated lists of their LSDBs.
- They negotiate the election process if they are on a multiaccess network.
- They exchange DBD packets in order to advertise parameters such as hello and dead intervals.
- They request more information about their databases.
15. Which statement is correct about multiarea OSPF?
- OSPF can consolidate a fragmented OSPF area into one large area.
- Arranging routers into areas partitions a large autonomous system in order to lighten the load on routers.
- All routers are in one area called the backbone area (area 0).
- OSPF multiarea increases the frequency of SPF calculation.
16. Which OSPF data structure is identical in all routers in an OSPF area after convergence?
- Adjacency database
- Link-state database
- Routing table
- SPF tree
17. What are the purposes of an OSPF router ID? (Choose two.)
- To enable the SPF algorithm to determine the lowest-cost path to remote networks
- To facilitate router participation in the election of the designated router
- 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
18. Which statement describes a multiarea OSPF network?
- It consists of multiple network areas that are daisy-chained together.
- It has a core backbone area with other areas connected to the backbone area.
- It has multiple routers that run multiple routing protocols simultaneously, and each protocol consists of an area.
- It requires a three-layer hierarchical network design approach.
19. What are the advantages of using multiarea OSPF? (Choose two.)
- A backbone area is not required.
- It allows OSPFv2 and OSPFv3 to run together.
- It enables multiple routing protocols to run in a large network.
- It improves routing efficiency by reducing the routing table and linkstate update overhead.
- It improves routing performance by dividing the neighbor table into separate smaller ones.
- Topology changes in one area do not cause SPF recalculations in other areas.
20. Which command can be used to verify the contents of the LSDB in an OSPF area?
- show ip ospf database
- show ip ospf interface
- show ip ospf neighbor
- show ip route ospf
21. Which of the following facilitates hierarchical routing in OSPF?
- 1. Auto-summarization
- 2. Frequent SPF calculations
- 3. The election of designated routers
- 4. The use of multiple areas
22. Which step does an OSPF-enabled router take immediately after the OSPF router builds the topology table?
- Chooses the best path
- Establishes an adjacency with another router
- Exchanges link-state advertisements
- Executes the SPF algorithm
23. 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 Acknowledgment
- Link-State Request
- Link-State Update
24. Which OSPF states are performed prior to two routers forming a neighbor adjacency? (Choose three.)
25. In an OSPF network, when are DR and BDR elections required?
- 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 two adjacent neighbors are interconnected over a point-topoint link
26. When an OSPF network is converged and no network topology change has been detected by a router, how often are LSU packets sent to neighboring routers?
- Every 10 seconds
- Every 40 seconds
- Every 15 minutes
- Every 30 minutes