ENSA - Module 1 - OSPF Single Area Concepts

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 secs
• 15 secs
• 30 secs
• 45 secs
• 75 secs

What is identical on all OSPF routers within a single area?

• Routing table
• Topology table
• Neighbor table
• Link-state database
• Database Description

What is used to facilitate hierarchical routing in OSPF? (Choose two)

• Frequent SPF calculations
• Autosummarisation
• The use of multiple areas
• Backbone area
• Election of Designated routers

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.)

• OSPF process ID
• Hello interval
• Router priority
• LSDB
• Dead interval

In an OSPF network when are DR and BDR elections required?

• In a multiaccess Ethernet network
• When all the routers in an OSPF area cannot form adjacencies
• In a Point-to-Point network
• When the two adjacent neighbors are in two different networks
• When hello packets are not received

In which OSPF state is the DR/BDR election conducted?

• Init
• Exstart
• Two-Way
• Loading State
• Exchange state

Which step does an OSPF-enabled router take immediately after establishing an adjacency with another router?

• Sttart sending Hello packets
• Build the topology table
• Execute the SFP algorithm
• Choose the best path
• Exchange link-state advertisements

Two OSPF-enabled routers are connected over a point-to-point link. During the ExStart state, which router will be chosen as the first one to send DBD packets?

• Router with the lowest router ID
• Router with the lowest IP address on the conecting interface
• Router with the highest router ID
• Router with the highest IP address on the connecting interface
• Router with lowest loopback address

What indicates to a link-state router that a neighbor is unreachable?

• If the router no longer receives routing updates
• If the router no longer receives hello packets
• If the router no longer receives acknowledgements
• If the router is not in the routing table
• If the router receives an LSP with previously learned information

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 R3 will become the BDR
• Router R1 will become the DR and router R2 will become the BDR
• Router R3 will become the DR and router R2 will become the BDR
• Router R3 will become the DR and R1 will become the BDR
• Router R4 will become the DR and R1 will become the BDR