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N10-009 Network Implementation Practice Question

A network administrator is configuring OSPF on a router that has interfaces in only one area and does not perform route redistribution. Which OSPF router type best describes this router?

⚠ Common exam trap

The N10-009 exam often tests the distinction between an internal router and an ABR by making candidates assume that any router not in area 0 is an internal router, but the trap is that an ABR must have interfaces in multiple areas, while an internal router has all interfaces in a single area regardless of which area it is.

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

Internal router

An internal router has all its interfaces in a single OSPF area and does not perform route redistribution. Since the router's interfaces are confined to one area and it does not connect to other routing domains, it fits the definition of an internal router. This type of router maintains a single link-state database for that area and does not generate Type 3 or Type 5 LSAs.

Answer analysis

Option-by-option breakdown

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

  • Backbone router

    Why it's wrong here

    A backbone router is specifically defined by having at least one interface connected to OSPF Area 0, the backbone area. While a router can be an internal router within Area 0, the term 'backbone router' emphasizes its participation in the core routing infrastructure. The question only states 'one area,' which could be any area, not necessarily Area 0, making this option incorrect.

    When this WOULD be correct

    If the question specified that the router has at least one interface in Area 0, even if it also has interfaces in other areas, then it would be a backbone router.

  • Internal router

    Why this is correct

    An internal router operates entirely within a single OSPF area and does not have any interfaces connecting to other OSPF areas or external routing domains. Its primary function is to maintain a link-state database for its local area and forward traffic within that area. The description perfectly matches this role, as the router has interfaces in only one OSPF area.

  • Area Border Router (ABR)

    Why it's wrong here

    An Area Border Router (ABR) is characterized by having interfaces in multiple OSPF areas, with at least one interface always connected to Area 0. Its crucial role is to summarize and propagate routing information between different OSPF areas, facilitating inter-area routing. Since the described router has interfaces in only one OSPF area, it cannot function as an ABR.

    When this WOULD be correct

    This option would be correct in a question where a router has interfaces in at least two different OSPF areas and is responsible for routing between them, summarizing routes from one area to another.

  • Autonomous System Boundary Router (ASBR)

    Why it's wrong here

    An Autonomous System Boundary Router (ASBR) is responsible for exchanging routing information between an OSPF autonomous system and another routing domain, such as EIGRP, RIP, or a static routing environment. This router performs route redistribution, importing external routes into OSPF and potentially exporting OSPF routes. The question makes no mention of external connections or redistribution, thus this role does not apply.

    When this WOULD be correct

    A router that redistributes external routes (e.g., from EIGRP or BGP) into OSPF, regardless of its interfaces being in one or multiple areas, would be correctly identified as an ASBR.

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 N10-009 exam frequently reuses these exact scenarios with slightly different constraints.

Internal routerCorrect answer

Why this is correct

An internal router operates entirely within a single OSPF area and does not have any interfaces connecting to other OSPF areas or external routing domains. Its primary function is to maintain a link-state database for its local area and forward traffic within that area. The description perfectly matches this role, as the router has interfaces in only one OSPF area.

Backbone routerWrong answer — click to see why

Why this is wrong here

A backbone router must have at least one interface in Area 0, but the question states the router has interfaces in only one area, which is not necessarily Area 0.

★ When this WOULD be the correct answer

If the question specified that the router has at least one interface in Area 0, even if it also has interfaces in other areas, then it would be a backbone router.

Why candidates choose this

Candidates often assume that any OSPF router in a single-area network must be a backbone router, forgetting that the backbone is specifically Area 0.

Area Border Router (ABR)Wrong answer — click to see why

Why this is wrong here

An Area Border Router (ABR) connects multiple OSPF areas, but the question states the router has interfaces in only one area, so it cannot be an ABR.

★ When this WOULD be the correct answer

This option would be correct in a question where a router has interfaces in at least two different OSPF areas and is responsible for routing between them, summarizing routes from one area to another.

Why candidates choose this

Candidates may confuse the term 'area border' with any router that is at the edge of an area, not realizing that ABR specifically requires multiple area connections.

Autonomous System Boundary Router (ASBR)Wrong answer — click to see why

Why this is wrong here

An ASBR is a router that redistributes routes from other routing protocols or autonomous systems into OSPF. The question states the router does not perform route redistribution, so it cannot be an ASBR.

★ When this WOULD be the correct answer

A router that redistributes external routes (e.g., from EIGRP or BGP) into OSPF, regardless of its interfaces being in one or multiple areas, would be correctly identified as an ASBR.

Why candidates choose this

Candidates may confuse the term 'Autonomous System Boundary Router' with any router that connects to external networks, or they may mistakenly think that any router with multiple interfaces is an ASBR.

Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Visual reference

R1 R2 R3 R4 10 100 10 100 OSPF picks R1→R2→R4 (cost 20) over R1→R3→R4 (cost 200)

Quick reference

Routing Protocol Comparison

ProtocolMetricMax HopsAlgorithmType
RIP v2Hop count15Bellman-FordDistance vector
OSPFCost (bandwidth)UnlimitedDijkstra (SPF)Link state
EIGRPComposite metricUnlimitedDUALHybrid
IS-ISCostUnlimitedDijkstraLink state
BGPPolicy / attributesUnlimitedPath vectorPath vector

RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.

About these practice questions

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 exam.