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Ethernet Switching And Spanning TreehardMultiple ChoiceObjective-mapped

JNCIP-ENT Ethernet Switching And Spanning Tree Practice Question

An engineer is troubleshooting a large-scale enterprise network with multiple MSTP regions connected by a legacy RSTP region. How do boundary switches running MSTP interact with RSTP switches on shared segments?

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

MSTP boundary ports detect RSTP BPDUs and operate in RSTP compatibility mode on that specific port.

MSTP bridge ports connected to RSTP regions automatically downgrade their communication mode to interoperate with RSTP/STP BPDUs.

Answer analysis

Option-by-option breakdown

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

  • MSTP boundary ports drop all RSTP BPDUs and treat the link as a point-to-point blocked topology.

    Why it's wrong here

    Boundary ports do not drop BPDUs; they interact by sending MST BPDUs that are understood by RSTP devices as standard BPDUs.

  • The entire MSTP region converts its configuration digest to match the RSTP region's default region name.

    Why it's wrong here

    Regions do not dynamically alter their internal configuration digests based on external devices.

  • MSTP boundary ports detect RSTP BPDUs and operate in RSTP compatibility mode on that specific port.

    Why this is correct

    MSTP bridges automatically migrate ports connecting to RSTP/STP regions to legacy mode for compatibility.

  • MSTP isolates the RSTP region into a separate MSTI instance automatically.

    Why it's wrong here

    MSTI mapping requires manual configuration.

Visual reference

SW1 Root Bridge SW2 SW3 BLK DP DP RP RP STP blocks one link to prevent loops DP = Designated Port RP = Root Port BLK = Blocked

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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.