Question 320 of 1,819

IP Routing →mediumDrag & DropObjective-mapped

Quick Answer

The correct answer is that the new router sends Hello packets, enters ExStart state with the DR and BDR, and then forms full adjacency with both. This is because in a multiaccess network with an already elected Designated Router and Backup Designated Router, the OSPF DR/BDR election is non-preemptive—meaning a new router, regardless of its priority or Router ID, cannot trigger a new election. Instead, it must establish full adjacencies with both the DR and BDR to ensure the network’s link-state database is synchronized. On the CCNA 200-301 v2 exam, this concept often appears as a drag-and-drop ordering task, testing your understanding that the new router does not become DR/BDR and does not skip the ExStart state with the BDR. A common trap is assuming the new router only forms a full adjacency with the DR, but OSPF requires full two-way adjacency with both the DR and BDR for proper flooding. Memory tip: “New kid on the block—say hello to both the principal and the vice principal, not just the principal.”

CCNA IP Routing Practice Question

This 200-301 practice question tests your understanding of ip routing. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.

Drag and drop the following OSPFv2 DR/BDR election steps into the correct order for a multiaccess network where a new router is added after the DR and BDR have already been elected.

Question 1mediumdrag order

Review the full OSPF breakdown →

A
The new router sends Hello packets with priority 0, remains in 2-Way state with DR and BDR, then forms full adjacency with the DR.
Why wrong: A router with priority 0 does not participate in DR/BDR election. It will stay in 2-Way state with the DR and BDR and then form a full adjacency with the DR only.
B
The new router sends Hello packets, becomes the new DR after election, and then forms adjacencies with all other routers.
This is incorrect because a new router with priority 0 cannot become DR. If priority is not 0, a new router could become DR only if its priority is higher than the current DR, but the question implies priority 0.
C
The new router sends Hello packets, becomes the new BDR after election, and then forms adjacencies with the DR and all other routers.
This is incorrect because a router with priority 0 cannot become BDR. It will not participate in the election at all.
D
The new router sends Hello packets, enters ExStart state with the DR and BDR, and then forms full adjacency with both.
Regardless of its OSPF priority, the new router enters ExStart state with both the DR and BDR and then forms full adjacencies with both.

Full breakdown with real-world context →

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 new router sends Hello packets, becomes the new DR after election, and then forms adjacencies with all other routers.

When a new router joins a multiaccess network that already has DR/BDR, it goes through the ExStart state with both the DR and BDR, then forms full adjacencies with both, regardless of its OSPF priority. Options A, B, and C are incorrect because they either describe adjacencies with only the DR, or claim the new router becomes DR/BDR, which cannot happen when DR/BDR are already elected.

Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.

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 new router sends Hello packets with priority 0, remains in 2-Way state with DR and BDR, then forms full adjacency with the DR.
Why it's wrong here
A router with priority 0 does not participate in DR/BDR election. It will stay in 2-Way state with the DR and BDR and then form a full adjacency with the DR only.
When this WOULD be correct
This applies when adding a new router to an OSPF multiaccess network where DR/BDR already exist and the new router is configured with priority 0.
✓
The new router sends Hello packets, becomes the new DR after election, and then forms adjacencies with all other routers.
Why this is correct
This is incorrect because a new router with priority 0 cannot become DR. If priority is not 0, a new router could become DR only if its priority is higher than the current DR, but the question implies priority 0.
Related concept
OSPF neighbours must agree on key parameters.
✓
The new router sends Hello packets, becomes the new BDR after election, and then forms adjacencies with the DR and all other routers.
Why this is correct
This is incorrect because a router with priority 0 cannot become BDR. It will not participate in the election at all.
Related concept
OSPF neighbours must agree on key parameters.
✓
The new router sends Hello packets, enters ExStart state with the DR and BDR, and then forms full adjacency with both.
Why this is correct
Regardless of its OSPF priority, the new router enters ExStart state with both the DR and BDR and then forms full adjacencies with both.
Related concept
OSPF neighbours must agree on key parameters.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

✓The new router sends Hello packets, becomes the new DR after election, and then forms adjacencies with all other routers.Correct answer▾

Why this is correct

This is incorrect because a new router with priority 0 cannot become DR. If priority is not 0, a new router could become DR only if its priority is higher than the current DR, but the question implies priority 0.

✗The new router sends Hello packets with priority 0, remains in 2-Way state with DR and BDR, then forms full adjacency with the DR.Wrong answer — click to see why▾

Why this is wrong here

A router with OSPF priority 0 forms full adjacencies with both the DR and BDR, not only the DR, so it does not remain in 2-Way with the BDR.

★ When this WOULD be the correct answer

This applies when adding a new router to an OSPF multiaccess network where DR/BDR already exist and the new router is configured with priority 0.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Common exam traps

Common exam trap: OSPF can fail even when IP connectivity looks correct

OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.

Detailed technical explanation

How to think about this question

OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.

KKey Concepts to Remember

OSPF neighbours must agree on key parameters.
Router ID selection can affect neighbour relationships and LSDB output.
OSPF cost influences the preferred path.
A route can appear in OSPF information but not become the installed route.

TExam Day Tips

Check area mismatch first when OSPF adjacency fails.
Review passive interfaces when a network is advertised but no neighbour forms.
Use show ip ospf neighbor and show ip route clues carefully.

Key takeaway

OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.

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.

What to study next

Got this wrong? Here's your next step.

Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 200-301 OSPF questions on adjacency and route selection.

Related 200-301 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Network Infrastructure and Connectivity practice questions

Practise 200-301 questions linked to Network Infrastructure and Connectivity.

Switching and Network Access practice questions

Practise 200-301 questions linked to Switching and Network Access.

IP Routing practice questions

Practise 200-301 questions linked to IP Routing.

Network Services and Security practice questions

Practise 200-301 questions linked to Network Services and Security.

AI and Network Operations practice questions

Practise 200-301 questions linked to AI and Network Operations.

CCNA subnetting practice questions

Practise IPv4 subnetting, CIDR, masks, host ranges and subnet selection.

CCNA OSPF practice questions

Practise OSPF neighbours, router IDs, metrics, areas and routing-table interpretation.

CCNA VLAN practice questions

Practise VLANs, access ports, trunks, allowed VLANs and switching scenarios.

CCNA STP practice questions

Practise spanning tree, root bridge election, port roles and STP troubleshooting.

CCNA EtherChannel practice questions

Practise LACP, PAgP, port-channel behaviour and bundle requirements.

CCNA ACL practice questions

Practise standard and extended ACLs, permit/deny logic and traffic filtering.

CCNA NAT practice questions

Practise static NAT, dynamic NAT, PAT and inside/outside address translation.

Practice this exam

Start a free 200-301 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions 20 questions 30 questions 50 questions Timed 30

200-301 practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this 200-301 question test?

IP Routing — This question tests IP Routing — OSPF neighbours must agree on key parameters..

What is the correct answer to this question?

The correct answer is: The new router sends Hello packets, becomes the new DR after election, and then forms adjacencies with all other routers. — When a new router joins a multiaccess network that already has DR/BDR, it goes through the ExStart state with both the DR and BDR, then forms full adjacencies with both, regardless of its OSPF priority. Options A, B, and C are incorrect because they either describe adjacencies with only the DR, or claim the new router becomes DR/BDR, which cannot happen when DR/BDR are already elected.

What should I do if I get this 200-301 question wrong?

What is the key concept behind this question?

OSPF neighbours must agree on key parameters.

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

This 200-301 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 200-301 exam.