CCNA IP Routing Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Down, Init, 2-Way, ExStart, Exchange

  Why this is correct

  This is the correct OSPF neighbor state progression. Down is the initial state with no Hello received; Init is entered after receiving a Hello but without seeing itself in it; 2-Way confirms bidirectional communication when the router sees its own Router ID in the neighbor's Hello; ExStart performs master/slave election and initial DBD sequence number negotiation; Exchange then transfers Database Description packets. This order ensures that bidirectional reachability is established before any adjacency negotiation begins.

• ✗

  Down, 2-Way, Init, ExStart, Exchange

  Why it's wrong here

  This is incorrect because it places 2-Way before Init, which is logically impossible: a router cannot reach the bidirectional 2-Way state before it has even received a Hello (Init). The Init state is triggered by the first received Hello, while 2-Way requires the router to see its own Router ID in a subsequent Hello from the neighbor, confirming that communication is bidirectional. Additionally, moving ExStart immediately after Init skips the mandatory 2-Way confirmation that must precede master/slave election.

• ✗

  Down, Init, ExStart, 2-Way, Exchange

  Why it's wrong here

  This is wrong because ExStart is sequenced too early, before the 2-Way state. ExStart is the master/slave election and DBD sequence number negotiation, which should only begin after 2-Way has confirmed that both routers can see each other in Hello packets; without that bidirectional confirmation, there is no verified path for DBD exchange. The correct order is Down → Init → 2-Way → ExStart → Exchange, so placing ExStart before 2-Way violates the protocol's dependency between adjacency establishment and DBD synchronization.

• ✗

  Down, Init, 2-Way, Exchange, ExStart

  Why it's wrong here

  This is wrong because Exchange is placed before ExStart, but ExStart must complete first. During ExStart, the routers elect a master and slave and agree on the initial DBD sequence numbers; the Exchange state then uses those negotiated parameters to send and acknowledge Database Description packets. Without the ExStart negotiation, routers would not know who controls the sequence numbering, making DBD exchange unreliable and potentially out of sync.

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.

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?”