Practice Test Geeks(STP) Spanning Tree Protocol Practice Test
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Clinical & Scientific Knowledge Flashcards

7 cards from real STP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Clinical & Scientific Knowledge flashcards as text

  1. What is a unidirectional link failure and which STP feature is designed to detect it?

    Answer: A fiber link where one direction fails, detected by UDLD

    UDLD (Unidirectional Link Detection) detects fiber links where traffic flows in only one direction, which STP cannot detect and which can cause loops.

  2. In STP, what is the total default convergence time when a direct link to the root bridge fails?

    Answer: 50 seconds

    Default STP convergence is MaxAge (20s) + 2× Forward Delay (2×15s) = 50 seconds.

  3. Which STP feature is specifically designed to speed up convergence when an indirect failure (non-direct path) to the root occurs?

    Answer: BackboneFast

    BackboneFast reduces convergence time for indirect failures by immediately expiring MaxAge and sending Root Link Queries (RLQs).

  4. A switch running PVST+ has 100 VLANs configured. How many STP instances is it running?

    Answer: 100

    PVST+ runs one independent STP instance per VLAN, so 100 VLANs means 100 separate spanning tree processes.

  5. What is the purpose of Root Guard in STP?

    Answer: Prevents a designated port from accepting superior BPDUs that would make the connected switch root

    Root Guard prevents a port from becoming a root port by placing it in root-inconsistent state if a superior BPDU is received.

  6. In the STP decision process, what is the fourth and final tiebreaker used to select a root port?

    Answer: Lowest port ID on the local switch

    The four STP tiebreakers in order are: lowest root path cost, lowest sender Bridge ID, lowest sender port ID, and lowest local port ID.

  7. When is an RSTP port considered to be on a 'point-to-point' link, enabling rapid transition?

    Answer: When the port operates in full-duplex mode

    RSTP automatically determines a link is point-to-point if the port operates in full-duplex, which allows the proposal/agreement handshake and rapid transition.