🌳 Spanning Tree Protocol - CCNA Practice Questions

Understand STP, RSTP, and PVST+ operation: root bridge election, port roles (root, designated, blocking), port states, and how STP prevents Layer 2 loops.

5Questions Available
1Exam Domains

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CCNA STP Question Bank (5 Questions)

Browse all 5 practice questions covering Spanning Tree Protocol for the CCNA certification exam. Each question includes the full answer and a detailed explanation to help you understand the concepts.

  1. Question 1Network Access

    How is the STP root bridge elected?

    AThe switch with the highest MAC address
    BThe switch with the lowest Bridge ID (priority + MAC address) — default priority is 32768, lower values are preferred✓
    CThe first switch powered on
    DRandom selection
    Show Answer & Explanation
    Correct Answer: B
    Explanation:

    Root bridge election: lowest Bridge ID wins. Bridge ID = Priority (32768 default, in increments of 4096) + System ID Extension (VLAN) + MAC address. To force a switch as root: 'spanning-tree vlan <id> priority 0' or 'spanning-tree vlan <id> root primary'.

  2. Question 2Network Access

    What are the port states in Rapid Spanning Tree Protocol (RSTP)?

    ABlocking, Listening, Learning, Forwarding, Disabled
    BDiscarding, Learning, and Forwarding — RSTP consolidates STP's Blocking, Listening, and Disabled into Discarding✓
    CActive and Inactive
    DUp and Down
    Show Answer & Explanation
    Correct Answer: B
    Explanation:

    RSTP (802.1w) simplifies STP states: Discarding (combines blocking/listening/disabled — no data forwarding), Learning (building MAC table), Forwarding (active). RSTP converges in seconds vs. 30-50 seconds for legacy STP.

  3. Question 3Network Access

    In the Rapid Spanning Tree Protocol (RSTP, 802.1w), which port role replaces the blocking state from classic STP?

    AAlternate port✓
    BBackup port
    CDesignated port
    DRoot port
    Show Answer & Explanation
    Correct Answer: A
    Explanation:

    In RSTP, the alternate port provides a backup path to the root bridge and is functionally equivalent to the blocking state in classic STP (802.1D). A backup port provides a backup to a designated port on the same segment. Alternate ports can quickly transition to forwarding if the root port fails.

  4. Question 4Network Access

    In RSTP (802.1w), which port role replaces the non-designated port role from classic STP?

    ABackup port
    BAlternate port✓
    CEdge port
    DDisabled port
    Show Answer & Explanation
    Correct Answer: B
    Explanation:

    RSTP introduces the alternate port role, which provides a backup path to the root bridge and replaces the non-designated blocking port from STP.

  5. Question 5Network Access

    What is the default STP bridge priority value on Cisco switches?

    A0
    B4096
    C32768✓
    D65535
    Show Answer & Explanation
    Correct Answer: C
    Explanation:

    The default bridge priority is 32768. It can be changed in increments of 4096. Lower priority is preferred for root bridge election.

Key STP Concepts for CCNA

stprstppvstroot bridgeroot portdesignated portblockingforwardingbridge prioritybpdu

CCNA STP Exam Tips

Spanning Tree Protocol questions in CCNA are typically scenario-based. Focus on service-level decision making aligned to official exam objectives. Priority concepts: stp, rstp, pvst, root bridge, root port, designated port.

What CCNA Expects

  • Anchor your answer in select the most practical, secure, and scalable answer for the stated scenario.
  • STP scenarios for CCNA are frequently mapped to Domain 2 (20%), so read the objective carefully before picking controls or architecture.
  • Expect multi-service scenarios where STP interacts with IAM, networking, storage, or observability patterns rather than appearing as an isolated service question.
  • When two options are both technically valid, prefer the choice that best aligns with the exam's operational scope (Associate) and managed-service best practices.

High-Value STP Concepts

  • Know the core STP building blocks cold: stp, rstp, pvst, root bridge.
  • Review the edge-case features and limits for root port, designated port; these details are commonly used to differentiate answer choices.
  • Practice service-integration reasoning: how STP pairs with Switching, EtherChannel, Network Fundamentals in real deployment patterns.
  • For CCNA, explain why the chosen STP design meets reliability, security, and cost expectations better than the alternatives.

Common CCNA Traps

  • Watch for answers that partially solve the requirement but miss operational constraints.
  • Questions in Network Access often include distractors that look correct for STP but violate least-privilege, durability, or availability requirements.
  • Avoid picking options purely by feature name; validate data path, failure handling, and governance impact before answering.
  • If the prompt hints at automation or repeatability, eliminate manual-only operational answers first.

Fast Review Checklist

  • Can you compare at least two STP implementation paths and justify which one best fits the scenario?
  • Can you map the chosen answer back to Network Access (20%) outcomes for CCNA?
  • Can you explain security and access boundaries for STP without relying on default-open assumptions?
  • Can you describe how STP integrates with Switching and EtherChannel during failure, scaling, and monitoring events?

Exam Domains Covering STP

Domain 2Network Access20%

Related Resources

🎯 Free CCNA Mock Exam📝 Switching Questions📝 EtherChannel Questions📝 Network Fundamentals Questions

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