Question 1easymultiple choice
Full question →easymultiple choiceObjective-mapped
Which OSPF neighbor state indicates that the routers have already exchanged full link-state databases?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
2-WAY
2-WAY means bidirectional hellos, but not full database exchange.
B
Distractor review
EXSTART
EXSTART is the master-slave negotiation stage.
C
Best answer
FULL
FULL indicates the neighbors are fully adjacent.
D
Distractor review
INIT
INIT means a hello was seen, but bidirectional communication is not confirmed yet.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is selecting the 2-WAY or EXSTART states as the answer because they represent important steps in OSPF neighbor formation. However, 2-WAY only confirms bidirectional hello packets without database exchange, and EXSTART is merely the negotiation phase for database synchronization. Choosing these states overlooks the fact that full link-state database exchange and adjacency completion only occur at the FULL state. Misunderstanding this can lead to incorrect assumptions about OSPF neighbor readiness and routing stability.
Technical deep dive
How to think about this question
OSPF (Open Shortest Path First) is a link-state routing protocol that establishes neighbor relationships through a series of defined states. These states represent the progress of adjacency formation and database synchronization between routers. The process begins with the INIT state, where a router detects a hello packet from a neighbor but has not yet confirmed bidirectional communication. It then moves to the 2-WAY state, confirming bidirectional communication but not yet exchanging routing information. The EXSTART state follows, where routers negotiate master-slave roles to coordinate the database exchange process. The critical state for full adjacency is the FULL state, which signifies that both routers have successfully exchanged their entire link-state databases and are synchronized. This state ensures that both routers have identical topology information, allowing them to make consistent and accurate routing decisions. The transition through these states is essential for OSPF's reliable operation, as it prevents routing loops and inconsistencies by confirming database synchronization before forwarding traffic. A common exam trap is confusing the 2-WAY or EXSTART states with FULL. While 2-WAY confirms bidirectional communication and EXSTART initiates database exchange, neither guarantees complete synchronization. In practical networking, routers in the FULL state can immediately forward traffic based on the synchronized database, whereas routers in earlier states cannot. Understanding these distinctions is vital for troubleshooting OSPF adjacencies and ensuring network stability.
KKey Concepts to Remember
- OSPF neighbors progress through specific states during adjacency formation, culminating in the FULL state when link-state databases are fully synchronized.
- The FULL state in OSPF indicates that routers have completed the exchange of their entire link-state databases and are fully adjacent.
- OSPF uses a master-slave relationship during the EXSTART state to negotiate the initial sequence number for database exchange.
- The INIT state in OSPF means a router has received a hello packet but has not yet confirmed bidirectional communication with the neighbor.
- The 2-WAY state in OSPF confirms bidirectional communication but does not guarantee full database synchronization.
- OSPF adjacency states ensure reliable and consistent routing information by controlling the database exchange process step-by-step.
- Routers in the FULL state can forward traffic based on the synchronized link-state database, ensuring accurate routing decisions.
- Understanding OSPF neighbor states helps prevent misinterpretation of adjacency status and supports troubleshooting routing issues effectively.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
OSPF neighbors progress through specific states during adjacency formation, culminating in the FULL state when link-state databases are fully synchronized.
What is the correct answer to this question?
The correct answer is: FULL — FULL means the adjacency is complete and database synchronization has finished. States such as INIT, 2-WAY, EXSTART, and EXCHANGE all occur earlier in the process.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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