Are you ready to master ospf interview questions and boost your networking potential? Our CCNA OSPF quiz is designed to challenge your expertise with interview questions for ospf, covering modules 1 - 2: ospf concepts and configuration exam essentials. Whether you're refining your understanding of link-state routing or preparing for real-world scenarios, this OSPF quiz questions collection gives you a hands-on edge. You'll get instant feedback with detailed explanations, so you can identify gaps and track your progress. Ready to level up? Explore ospf interview questions or test your knowledge now!
What metric does OSPF use to determine the best path?
Hop count
Cost
Delay
Bandwidth
OSPF uses a composite cost metric based on interface bandwidth to select the best route. Lower cost paths are preferred over higher cost paths. The cost is calculated as the reference bandwidth divided by the interface bandwidth. For further details, see Cisco OSPF Overview.
Which type of routing protocol is OSPF?
Link-state
Distance-vector
Path-vector
Hybrid
OSPF is classified as a link-state routing protocol because it builds a complete map of network topology and uses SPF calculations. Link-state protocols share state information about the links rather than hop counts. This allows OSPF to converge quickly and scale well in large networks. Learn more at OSPF on Wikipedia.
What is the default hello interval on OSPF-enabled broadcast networks?
60 seconds
10 seconds
30 seconds
5 seconds
On broadcast and point-to-point networks, OSPF sends hello packets every 10 seconds by default. This interval helps routers discover and maintain neighbor adjacencies. Adjusting the hello interval can affect convergence time and neighbor relationships. More information can be found at Cisco OSPF Timers.
At which OSI layer does OSPF operate?
Layer 4 (Transport)
Layer 1 (Physical)
Layer 3 (Network)
Layer 2 (Data Link)
OSPF is an IP routing protocol that operates at OSI Layer 3 (the Network layer). It makes forwarding decisions based on IP addressing and routing tables. OSPF packets are encapsulated directly in IP, using protocol number 89. For further reading, see RFC 2328.
Which OSPF packet type is used to exchange database description information?
Link State Request
Link State Acknowledgment
Database Description
Hello
The Database Description (DBD) packet is used during adjacency formation to describe the contents of the OSPF link-state database. Each router advertises a summary of its LSDB entries via DBD. Neighbors use this to determine which LSAs they need. See DBD Packet Details for more.
Which OSPF LSA type is used to advertise external routes imported into the OSPF domain?
Type 5 (External LSA)
Type 1 (Router LSA)
Type 3 (Summary LSA)
Type 2 (Network LSA)
Type 5 LSAs, also called External LSAs, are flooded throughout the OSPF autonomous system to advertise routes redistributed from other routing protocols. They carry external network information and their costs. Internal OSPF routers use these to reach networks outside the OSPF domain. For details, refer to RFC 2328 Section on External LSAs.
What election occurs on a multiaccess network segment in OSPF?
Backbone router election
ABR election
DR election
ASBR election
On multiaccess networks such as Ethernet, OSPF elects a Designated Router (DR) and a Backup Designated Router (BDR) to reduce LSA flooding. The DR sends LSAs on behalf of the network segment. This election is based on priority and router ID if priorities are equal. More details are in OSPF DR/BDR Election.
Which command is used to manually set the OSPF router ID in Cisco IOS?
ip ospf id
router-id
neighbor router-id
set ospf router-id
Under the OSPF routing process configuration, the command 'router-id ' sets the OSPF router ID manually. This takes effect immediately or after process restart. If not configured, OSPF picks the highest IP on loopback or active interfaces. See Cisco Configuration Guide for syntax.
In OSPF adjacency formation, which state follows the Exchange state?
ExStart
Loading
Full
Init
After the Exchange state, where routers exchange DBD packets, OSPF moves to the Loading state to request any missing LSAs. In Loading, routers send Link State Request packets for more details. Once all LSAs are received, adjacency reaches Full state. See RFC 2328 Section 10 for a full state description.
Which OSPF area type allows external Type 7 LSAs but blocks Type 5 LSAs?
Not-So-Stubby Area (NSSA)
Totally stubby area
Backbone area
Stub area
An NSSA (Not-So-Stubby Area) permits the injection of external routes as Type 7 LSAs but prevents Type 5 LSAs from flooding into the area. An ABR later translates Type 7 to Type 5 for inter-area propagation. NSSAs are used when redistributing external routes into a mostly stub environment. For more, see Cisco NSSA Overview.
What is the default dead interval on an OSPF broadcast network?
20 seconds
30 seconds
40 seconds
120 seconds
OSPF uses a dead interval to determine when a neighbor is declared down, set by default to four times the hello interval (4 × 10s = 40s) on broadcast links. If no hello packets are received within this time, the neighbor is removed. Adjusting this can speed up or slow down failure detection. Read more at Cisco OSPF Timers.
In OSPF, which external metric type includes both external cost and internal OSPF cost when calculating the route preference?
E2 (Type 2 external)
E3 (Type 3 external)
E4 (Type 4 external)
E1 (Type 1 external)
Type 1 external LSAs (E1) include the external cost plus the internal path cost to the ASBR when computing the total metric. OSPF favors the lowest total cost, so E1 paths can sometimes be preferred to E2 despite higher external cost. Type 2 LSAs only consider external cost. For in-depth details, refer to RFC 2328 on External Metrics.
0
{"name":"What metric does OSPF use to determine the best path?", "url":"https://www.quiz-maker.com/QPREVIEW","txt":"What metric does OSPF use to determine the best path?, Which type of routing protocol is OSPF?, What is the default hello interval on OSPF-enabled broadcast networks?","img":"https://www.quiz-maker.com/3012/images/ogquiz.png"}
Score2/12
Easy1/4
Medium0/4
Hard1/3
Expert0/1
AI Study Notes
Email these to me
You can bookmark this page to review your notes in future, or fill out the email box below to email them to yourself.
Study Outcomes
Analyze OSPF Operation -
Understand OSPF interview questions on link-state routing by breaking down packet types and areas to tackle modules 1 - 2: OSPF concepts and configuration exam topics.
Configure OSPF Neighbors -
Apply step-by-step commands to establish OSPF neighbor relationships in real-world scenarios, prepping you for CCNA OSPF quiz challenges.
Troubleshoot OSPF Adjacencies -
Identify and resolve common OSPF adjacency issues, ensuring seamless area connectivity for robust network performance.
Interpret OSPF Metrics -
Calculate and compare cost metrics, enabling you to optimize routing paths and ace interview questions for OSPF efficiency evaluations.
Differentiate OSPF Area Types -
Examine the characteristics of backbone, stub, and NSSA areas to determine best-fit configurations and answer advanced quiz questions with confidence.
Simulate OSPF Topologies -
Build and test complex OSPF network designs in lab environments, sharpening your skills for the CCNA OSPF quiz and real-world deployments.
Cheat Sheet
Link-State Database and SPF Algorithm -
OSPF maintains a Link-State Database (LSDB) of all routers' Link State Advertisements (LSAs) to map the network topology (RFC 2328). Using Dijkstra's Shortest Path First (SPF) algorithm, it computes optimal, loop-free paths to every destination. Mnemonic "MAP-CALC": LSDB builds the map, SPF does the calculation.
OSPF Areas and Hierarchy -
OSPF uses a hierarchical area design with Area 0 as the backbone and other areas (standard, stub, NSSA) to optimize LSA flooding and routing table size (Cisco Live). Stub and NSSA areas limit external LSAs to reduce overhead. Memory trick: "B.S.N." - Backbone, Stub, NSSA.
Neighbor Adjacencies and DR/BDR Election -
Routers on multiaccess networks elect a Designated Router (DR) and Backup DR (BDR) using priority and router ID to minimize LSA exchanges (Juniper OSPF Guide). States move through Down→Init→2-Way→ExStart→Exchange→Loading→Full - use "Do I Rest Each Lunchtime Fully?" as a state mnemonic. Ensure matching hello intervals, dead timers, and area IDs to form adjacencies.
Cost Metric Calculation -
OSPF cost equals Reference Bandwidth (default 100 Mbps) divided by interface bandwidth, making higher-speed links cheaper paths (Cisco Documentation). For example, Gigabit links typically cost 1 (100 Mbps/1 Gbps). Change the reference bandwidth globally to support 10 Gbps+ environments.
Basic Configuration and Timers -
Key commands include "router ospf " and "network area " for area assignment (Cisco Press). Adjust hello and dead intervals with "ip ospf hello-interval" and "ip ospf dead-interval" on interfaces for network stability. Don't forget OSPF authentication types (none, plaintext, MD5) for secure neighbor relationships.
