Session 7

What algorithm does OSPF use to determine the best route?

• Bellman-Ford
• A* Algorithm
• Dijkstra's SPF Algorithm
• Flooding

Answer explanation

OSPF uses Dijkstra’s Shortest Path First to compute optimal paths.

What type of routing protocol is OSPF?

• Distance-vector
• Link-state
• Path-vector
• Static

Answer explanation

OSPF is a link-state protocol, meaning it maintains a full map of the network.

Which OSPF network type does not require DR/BDR election?

• Broadcast
• Point-to-Multipoint
• Non-Broadcast
• Point-to-Point

Answer explanation

Point-to-Point connections have only two devices, so no need for DR/BDR.

What is the purpose of OSPF Hello packets?

• To update routes
• To request more info
• To discover and maintain neighbors
• To acknowledge data

Answer explanation

Hello packets are used for neighbor discovery and to maintain adjacency.

Which OSPF state indicates full adjacency has been formed?

• 2-Way
• ExStart
• Full
• Init

Answer explanation

In Full state, routers have exchanged all necessary information.

What is the OSPF Administrative Distance (AD)?

• 90
• 100
• 120
• 110

Answer explanation

OSPF has an AD of 110, more preferred than RIP but less than EIGRP.

Which OSPF router type connects different areas?

• IR
• BR
• ASBR
• ABR

Answer explanation

ABR (Area Border Router) connects backbone and non-backbone areas.

Why are DR/BDR used in OSPF?

• For encryption
• For load balancing
• To reduce traffic
• To increase routing speed

Answer explanation

DR/BDR help reduce OSPF traffic in broadcast networks.

How is OSPF cost calculated?

• 100 / Bandwidth
• Bandwidth / 100
• Latency * Distance
• Distance + Delay

Answer explanation

Cost = Reference Bandwidth / Interface Bandwidth.

What happens during the Exchange state in OSPF?

• Database exchange begins
• Neighbors are discovered
• Routes are removed
• Master/Slave negotiation

Answer explanation

DBD packets are exchanged during the Exchange state.