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Interior Gateway ProtocolsmediumMultiple SelectObjective-mapped

JNCIP-ENT Interior Gateway Protocols Practice Question

Which THREE parameters must match between two OSPF routers on a shared broadcast segment for an adjacency to successfully form? (Choose three)

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

Router ID

OSPF hello/dead timers, area ID, and authentication parameters must match between neighbors to establish an adjacency.

Answer analysis

Option-by-option breakdown

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

  • Router ID

    Why this is correct

    Duplicate Router IDs will prevent adjacencies from forming, and they must be unique within the OSPF domain.

  • Area ID

    Why this is correct

    Interfaces connected to the same segment must belong to the same OSPF Area ID.

  • Hello and Dead interval timers

    Why this is correct

    Hello and dead timers must match exactly on both ends of an OSPF interface for neighbors to form adjacencies.

  • Interface MTU size

    Why it's wrong here

    While MTU mismatch can cause issues in some implementations if strict-mtu is enabled, it is not one of the fundamental mandatory database synchronization checks like Area ID or timers (though Junos ignores MTU by default unless configured).

  • Interface primary IP address subnet

    Why it's wrong here

    OSPF can form unnumbered or secondary IP adjacencies depending on configuration, though primary subnets usually match. The core required match parameters are Area ID, timers, and authentication.

Visual reference

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

About these practice questions

Courseiva writes every JNCIP-ENT question from scratch — 336 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →

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JA

Written and reviewed by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

Last reviewed August 2026 · checked against the official Juniper Networks exam blueprint

This JNCIP-ENT practice question is part of Courseiva's free Juniper Networks 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 JNCIP-ENT exam.