Cisco CCNA Single-Area OSPFv2 Configuration 3

Question 1

A router shows 'OSPF: Hello from 192.168.1.2 with mismatched area ID'. What is the most likely cause?

Accepted Answer

One interface is in area 0 and the other is in a different area

Answer

An area ID mismatch means the two interfaces are configured in different OSPF areas, preventing adjacency.

Question 2

What is the purpose of the OSPF DR (Designated Router) on a broadcast network?

Accepted Answer

To reduce LSA flooding by acting as a central point for LSDB synchronization

Answer

The DR reduces OSPF traffic on multi-access segments by collecting and distributing LSAs on behalf of all routers.

Question 3

Which OSPF state indicates that two routers have fully synchronized their Link State Databases?

Accepted Answer

Full

Answer

The Full state means both routers have identical LSDBs and the adjacency is complete.

Question 4

A Cisco router has 'passive-interface GigabitEthernet0/1' configured under OSPF. What is the effect?

Accepted Answer

Gi0/1 still advertises its network but does not send or receive Hello packets

Answer

A passive interface suppresses Hello packets so no adjacencies form, but the network is still advertised into OSPF.

Question 5

What is the OSPF cost of an interface with a bandwidth of 100 Mbps using the default reference bandwidth?

Accepted Answer

1

Answer

OSPF cost = reference bandwidth (100 Mbps) / interface bandwidth (100 Mbps) = 1.

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