Practice Test Geeks(STP) Spanning Tree Protocol Practice Test
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Configuration and Management 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 Configuration and Management flashcards as text

  1. A switch port remains in blocking state even though it should be forwarding. Which tool helps identify whether Root Guard or Loop Guard is the cause?

    Answer: show spanning-tree inconsistentports

    The 'show spanning-tree inconsistentports' command lists all ports currently in a root-inconsistent or loop-inconsistent state caused by Root Guard or Loop Guard.

  2. How does Rapid STP (802.1w) achieve faster convergence compared to 802.1D?

    Answer: It uses a proposal/agreement handshake to transition ports to forwarding without waiting for timers

    RSTP uses a proposal/agreement mechanism between directly connected switches to synchronize port roles and states without relying on timer expiry.

  3. Which RSTP port role is equivalent to the 802.1D blocking port and does not forward traffic but can quickly transition to forwarding?

    Answer: Alternate port

    The RSTP alternate port provides an alternate path to the root and can transition to root port role quickly if the current root port fails.

  4. What is the recommended practice when enabling BPDU Guard globally via 'spanning-tree portfast bpduguard default'?

    Answer: Ensure PortFast is also enabled globally so BPDU Guard activates only on PortFast ports

    When BPDU Guard is enabled globally, it activates only on PortFast-enabled interfaces, so PortFast must also be enabled globally or per-port for BPDU Guard to take effect.

  5. After a topology change in classic 802.1D STP, switches flush their MAC address tables. What timer controls how long this flushing behavior persists?

    Answer: Topology Change Notification (TCN) timer set to 35 seconds by default

    After a TCN, switches flush MAC entries using a timer equal to forward delay + max age (15+20=35 seconds) to prevent stale forwarding entries.

  6. Which configuration error would cause two switches running PVST+ to end up with different root bridges for the same VLAN?

    Answer: One switch having 'spanning-tree vlan 10 priority 0' and the other having 'spanning-tree vlan 10 priority 4096'

    If one switch has priority 0 and another has any higher priority, the switch with priority 0 wins the root election — but if the intent was both to be root, the configuration is conflicting.

  7. An administrator runs 'spanning-tree vlan 1 priority 32768' on a switch. What is the effect if this is the current root bridge?

    Answer: The switch may lose its root bridge role to another switch with a lower priority

    Setting priority to 32768 (the default) removes any manually lowered priority advantage, potentially causing another switch with a lower priority to become root.