hardMultiple Choice
350-401 Practice Question: Executes the following command on Router R5: R5#…
A network engineer executes the following command on Router R5:
R5# show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.0.0.6 1 FULL/DR 00:00:35 192.168.1.6 GigabitEthernet0/0 10.0.0.7 1 FULL/BDR 00:00:32 192.168.1.7 GigabitEthernet0/0 10.0.0.8 1 2WAY/DROTHER 00:00:38 192.168.1.8 GigabitEthernet0/0
Based on this output, what can be concluded about the OSPF network?
⚠ Common exam trap
Cisco often tests the misconception that all OSPF neighbors must be in FULL state for proper operation, but on broadcast networks, DROTHER routers remain in 2WAY state with each other to reduce LSA flooding overhead.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The OSPF network type is broadcast.
The output shows neighbors in states FULL/DR, FULL/BDR, and 2WAY/DROTHER, which are characteristic of a broadcast multiaccess network where a Designated Router (DR) and Backup Designated Router (BDR) are elected. The presence of a 2WAY/DROTHER state indicates that non-DR/BDR routers maintain a two-way adjacency without exchanging full LSDBs, which only occurs on broadcast or non-broadcast multiaccess (NBMA) networks. Since the network type is not point-to-point (which would show only FULL states) and the DR/BDR roles are present, the OSPF network type must be broadcast.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The OSPF network type is point-to-point.
Why it's wrong here
The 'show ip ospf neighbor' output on a point-to-point network would not include DR/BDR designations in the neighbor state column. In point-to-point OSPF, there is no DR/BDR election, and all neighbors are shown as FULL/- without any DR or BDR role. The presence of states like FULL/DR, FULL/BDR, and 2WAY/DROTHER in the output proves the network type is multiaccess, so point-to-point is incorrect.
- ✗
Router R5 is the DR on this segment.
Why it's wrong here
The output lists neighbors and their states; it does not directly display R5's own router ID or its DR/BDR role. The neighbor 10.0.0.6 is shown in the FULL/DR state, which means that 10.0.0.6 is the DR on this segment. R5 could be the BDR or a DROTHER, but based solely on this output, we cannot conclude that R5 is the DR.
- ✓
The OSPF network type is broadcast.
Why this is correct
The neighbor states FULL/DR, FULL/BDR, and 2WAY/DROTHER are only possible on OSPF network types that perform DR/BDR election, such as broadcast or NBMA. On a broadcast multiaccess network like Ethernet, OSPF elects a DR and BDR to reduce adjacencies, and DROTHER routers remain in 2WAY with each other. The router's output clearly shows a neighbor as the DR and another in the DROTHER state, confirming the network type is broadcast.
- ✗
All neighbors are in the FULL state.
Why it's wrong here
The output includes a neighbor in the 2WAY/DROTHER state, which is not a FULL adjacency. The 2WAY state occurs between two DROTHER routers on a broadcast network after they exchange Hello packets but do not form an adjacency because they are not the DR or BDR. Only the DR and BDR form FULL adjacencies with all routers on the segment, so the statement that all neighbors are in FULL state is false.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.