How many Spanning Tree Protocol Scenarios questions are on this page?

This page has 5 Spanning Tree Protocol Scenarios scenario questions for the 200-901 exam, each with detailed explanations and wrong-answer analysis.

How should I approach 200-901 scenario questions?

Read the full scenario before looking at the answer options. Identify the constraint or requirement in the scenario, then eliminate options that are generally true but wrong for this specific case. Scenario questions reward careful reading over pattern matching.

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Scenario-based practice

Spanning Tree Protocol Scenarios

Practise 200-901 STP questions covering root bridge election, bridge IDs, port roles (root, designated, blocking), path cost, PortFast, BPDU Guard, and how spanning tree prevents Layer 2 loops.

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scenario questions

200-901

exam code

Cisco

vendor

Scenario guide

How to approach spanning tree protocol scenarios

STP and Rapid PVST+ questions test your understanding of root bridge election, port roles, port states, and protection features. These appear in MCQ, multi-select, and drag-and-drop formats on the CCNA because STP behaviour is non-intuitive and frequently misunderstood.

Quick answer

STP questions usually test root bridge election, port roles, path cost and how spanning tree prevents Layer 2 loops.

Root bridge election and bridge ID comparison.

Root ports, designated ports and blocked/alternate ports.

Path cost and how switches choose the best path to the root bridge.

PortFast, BPDU Guard and common Layer 2 loop-prevention behaviour.

Practice scenarios

Question 1hardmultiple choice

Open the full BGP breakdown →

A company has a three-tier data center architecture with access, aggregation, and core layers. The network team is migrating to a leaf-spine architecture to support increasing east-west traffic. The current network uses STP for loop prevention, and the team wants to eliminate STP in the new design. They plan to use VXLAN overlays with BGP EVPN for control plane. During a pilot deployment, the team notices that some legacy servers that rely on traditional VLANs are not reachable across the new fabric. The servers are connected to access switches that are part of the leaf layer. The access switches are configured as VXLAN tunnel endpoints (VTEPs) but the legacy servers are still using traditional VLANs. The team needs to ensure connectivity between the legacy VLAN-based servers and the new VXLAN-based network. What is the best approach to integrate these legacy servers without changing their configuration?

A
Create a separate VRF for legacy VLANs and redistribute into BGP EVPN
Why wrong: This adds complexity and does not solve L2 connectivity.
B
Implement a Layer 2 gateway (L2GW) on the leaf switches to bridge VLANs to VXLAN using IRB
IRB provides seamless bridging between VLAN and VXLAN.
C
Configure the same VLAN on all leaf switches and use VXLAN to stretch the VLAN across the fabric
Why wrong: Stretching VLANs is not recommended for large fabrics.
D
Reconfigure the legacy servers to use VXLAN encapsulation
Why wrong: Server configuration change is to be avoided.

Full breakdown with real-world context →

Question 2hardmultiple choice

Open the full VLAN trunking answer →

During a network migration, an engineer needs to replace a legacy core switch with a new one without disrupting the existing STP topology. The new switch supports RSTP and will be connected via two trunk links. Which configuration should be applied to the new switch to prevent it from becoming the root bridge?

A
Enable root guard on the trunk ports
Why wrong: Root guard protects against inferior BPDUs, does not prevent this switch from becoming root.
B
Configure the bridge priority to 61440
High priority makes it less likely to become root.
C
Enable BPDU guard on the trunk ports
Why wrong: BPDU guard disables ports if BPDU received, not related to root election.
D
Set the bridge priority to 0
Why wrong: Priority 0 makes it the root.

Full breakdown with real-world context →

Question 3easymultiple choice

Open the full VLAN trunking answer →

Refer to the exhibit. A PC is connected to interface GigabitEthernet0/1 on a Cisco switch. The PC is in VLAN 10. What is the purpose of the 'spanning-tree portfast' command on this interface?

Exhibit

Refer to the exhibit.
```
interface GigabitEthernet0/1
 switchport mode access
 switchport access vlan 10
 spanning-tree portfast
```

A
It disables STP on the interface.
Why wrong: STP still runs but portfast bypasses listening/learning.
B
It prevents the interface from entering blocking state.
Why wrong: PortFast allows immediate forwarding, but blocking is still possible if BPDUs are received.
C
It allows the interface to transition directly to forwarding state.
PortFast eliminates the learning/listening delays.
D
It enables BPDU guard on the interface.
Why wrong: BPDU guard is a separate configuration.
E
It enables Rapid Spanning Tree on the interface.
Why wrong: PortFast does not enable RSTP; it is a feature for access ports.

Full breakdown with real-world context →

Question 4mediummultiple choice

Open the full VLAN trunking answer →

A network engineer notices that after a link failure, traffic to a server on a different VLAN is intermittent. The network uses Rapid PVST+. The switch connecting the server is a root bridge for that VLAN. What is the most likely cause of the intermittent connectivity?

A
The server port is not configured as an edge port, causing STP convergence delay.
Non-edge ports go through STP states, causing delays.
B
The server is sending BPDUs with a higher priority.
Why wrong: Servers typically don't send BPDUs.
C
The root bridge is flapping due to a configuration mismatch.
Why wrong: Root bridge flapping is not typical for rapid PVST+.
D
OSPF hold-down timers are preventing route updates.
Why wrong: Hold-down timers are for OSPF, not STP.

Full breakdown with real-world context →

Question 5easymultiple choice

Open the full VLAN trunking answer →

A company has two Cisco Catalyst switches, SW1 and SW2, connected via a trunk link using port GigabitEthernet0/1 on both switches. SW1 is the root bridge for all VLANs spanning tree. VLAN 10 users on SW1 report they can access the internet and resources in VLAN 10 on SW2, but cannot reach a critical server in VLAN 20 connected to SW2. The server in VLAN 20 has a static IP address and can communicate with other VLAN 20 devices on SW2. SW2's configuration for the trunk port includes 'switchport trunk allowed vlan 10,20'. SW1's trunk port configuration is 'switchport trunk allowed vlan 10'. The network administrator has verified that both switches have VLANs 10 and 20 created and that the default gateways are correct. What is the most likely cause of the issue?

A
SW1's trunk port is not configured to allow VLAN 20.
The trunk allowed VLAN list on SW1 only includes VLAN 10, so VLAN 20 traffic is blocked.
B
SW1 is the root bridge for VLAN 20, causing traffic to be blocked.
Why wrong: Being root bridge does not block traffic; STP only prevents loops.
C
The trunk link between SW1 and SW2 is down.
Why wrong: The trunk is up as VLAN 10 traffic works.
D
The server in VLAN 20 has an incorrect IP address configuration.
Why wrong: The server can communicate with other devices in VLAN 20, so IP configuration is correct.

Full breakdown with real-world context →

These 200-901 practice questions are part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style 200-901 questions with detailed explanations, topic-based practice, mock exams, readiness tracking, and study analytics.

Spanning Tree Protocol Scenarios

How to approach spanning tree protocol scenarios

Quick answer

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Practice scenarios

Refer to the exhibit. A PC is connected to interface GigabitEthernet0/1 on a Cisco switch. The PC is in VLAN 10. What is the purpose of the 'spanning-tree portfast' command on this interface?

Exhibit

A network engineer notices that after a link failure, traffic to a server on a different VLAN is intermittent. The network uses Rapid PVST+. The switch connecting the server is a root bridge for that VLAN. What is the most likely cause of the intermittent connectivity?