The answer is that R1 is a DROTHER on this broadcast multiaccess segment. This conclusion is drawn directly from the OSPF neighbor state output: R1 sees a neighbor in the 2WAY/DROTHER state, which means both routers are DROTHERs, as they have formed a two-way adjacency but have not progressed to a full database exchange with each other. The neighbor in the FULL/DR state is the Designated Router, and since R1 is neither the DR nor the BDR (no FULL/BDR entry), it must be a DROTHER. On the ENCOR 350-401 exam, this question tests your ability to interpret OSPF neighbor states in a broadcast multiaccess network, where the DR and BDR form FULL adjacencies with all routers, while DROTHERs remain in 2WAY with each other. A common trap is assuming a FULL state always indicates a router’s role; remember that FULL only confirms adjacency with the DR/BDR, not the router’s own status. Memory tip: “DROTHERs say ‘2WAY’ to each other, but go ‘FULL’ with the DR.”
350-401 OSPF Practice Question
This 350-401 practice question tests your understanding of ospf. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network engineer runs the following command on Router R1:
R1# show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
10.0.0.2 1 FULL/DR 00:00:32 192.168.1.2 GigabitEthernet0/0
10.0.0.3 1 2WAY/DROTHER 00:00:35 192.168.1.3 GigabitEthernet0/0
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
R1 is a DROTHER on this segment.
The output shows R1 has a neighbor with state 2WAY/DROTHER (10.0.0.3), which indicates that R1 is also a DROTHER on this broadcast multiaccess segment. The FULL/DR neighbor (10.0.0.2) is the Designated Router, and since R1 is not the BDR (no FULL/BDR state), it must be a DROTHER.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
R1 is the Backup Designated Router (BDR) on this segment.
Why it's wrong here
The state field does not show BDR; R1's own state is not displayed, but the neighbor states indicate R1 is a DROTHER.
✗
R1 has a full OSPF adjacency with the neighbor 10.0.0.3.
Why it's wrong here
The state for 10.0.0.3 is 2WAY, not FULL, so only a two-way relationship exists.
✓
R1 is a DROTHER on this segment.
Why this is correct
Since the DR is 10.0.0.2 and the BDR is not listed, and R1 has a full adjacency only with the DR, R1 must be a DROTHER.
Related concept
Read the scenario before looking for a memorised answer.
✗
The OSPF network type is point-to-point.
Why it's wrong here
The presence of DR/BDR states indicates a broadcast or NBMA network type, not point-to-point.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that 2WAY state means a full adjacency, but in OSPF, 2WAY is a normal neighbor state on broadcast networks between DROTHERs, not a full adjacency (which requires FULL state).
Trap categories for this question
Command / output trap
The state field does not show BDR; R1's own state is not displayed, but the neighbor states indicate R1 is a DROTHER.
Detailed technical explanation
How to think about this question
On broadcast multiaccess networks (e.g., Ethernet), OSPF elects a DR and BDR to reduce LSA flooding. DROTHERs form full adjacencies only with the DR and BDR, and remain in 2WAY state with each other. The 'show ip ospf neighbor' command reveals the router's own role: if it sees a neighbor as DROTHER in 2WAY, the local router is also a DROTHER.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 350-401 question in full detail.
OSPF — This question tests OSPF — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: R1 is a DROTHER on this segment. — The output shows R1 has a neighbor with state 2WAY/DROTHER (10.0.0.3), which indicates that R1 is also a DROTHER on this broadcast multiaccess segment. The FULL/DR neighbor (10.0.0.2) is the Designated Router, and since R1 is not the BDR (no FULL/BDR state), it must be a DROTHER.
What should I do if I get this 350-401 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A network engineer runs the following command on Router R9:
R9# show ip ospf interface brief
Interface PID Area IP Address/Mask Cost State Nbrs F/C
Gi0/0 1 0 192.168.1.9/24 10 DR 2/2
Gi0/1 1 1 10.0.0.9/24 20 BDR 1/1
Lo0 1 0 9.9.9.9/32 1 LOOP 0/0
Based on this output, what can be concluded?
medium
A.R9 is the Designated Router on the segment connected to Gi0/1.
✓ B.R9 has two fully adjacent neighbors on Gi0/0.
C.The loopback interface Lo0 is advertised as a /24 network.
D.R9 is an Area Border Router.
Why B: The output shows that on interface Gi0/0, R9 has a state of DR (Designated Router) and 2 fully adjacent neighbors (Nbrs F/C = 2/2). The '2/2' indicates 2 neighbors in a full state out of 2 total neighbors, meaning both neighbors have completed the OSPF adjacency process. Therefore, R9 has two fully adjacent neighbors on Gi0/0, making option B correct.
Last reviewed: Jun 24, 2026
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