Cisco CCNA Single-Area OSPFv2 Configuration 4

Question 1

After configuring OSPFv2, a router shows neighbor state as '2-Way' rather than 'Full'. What does this indicate?

Accepted Answer

Both routers see each other's Hellos but are not DR/BDR, which is normal for DROTHER routers

Answer

2-Way state is normal between two DROTHER routers on a multi-access segment; Full adjacency only forms with the DR and BDR.

Question 2

What is the multicast address used by OSPFv2 to send Hello packets to all OSPF routers?

Accepted Answer

224.0.0.5

Answer

OSPFv2 uses 224.0.0.5 (AllSPFRouters) to send Hello packets and LSAs to all OSPF-enabled routers.

Question 3

A router's OSPF neighbor table shows a neighbor stuck in the 'EXSTART' state. What is the most likely cause?

Accepted Answer

Duplicate OSPF router IDs on the network

Answer

Duplicate router IDs cause OSPF to get stuck in ExStart because routers cannot agree on master/slave roles during DBD exchange.

Question 4

Which command manually sets the OSPF cost on an interface to 50?

Accepted Answer

ip ospf cost 50 (interface mode)

Answer

The 'ip ospf cost value' command in interface configuration mode directly sets the OSPF cost for that interface.

Question 5

How does OSPFv2 handle equal-cost paths to the same destination by default on Cisco routers?

Accepted Answer

Traffic is load-balanced across up to 4 equal-cost paths

Answer

Cisco routers perform equal-cost load balancing (ECMP) across up to 4 paths by default when OSPF finds multiple equal-cost routes.

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