Spanning Tree Protocol Scenarios

A network engineer runs the following command on Switch SW1:

SW1# show interfaces trunk

Port Mode Encapsulation Status Native vlan Gi0/1 on 802.1q trunking 1 Gi0/2 on 802.1q trunking 1

Port Vlans allowed on trunk Gi0/1 1-1005 Gi0/2 1-1005

Port Vlans allowed and active in management domain Gi0/1 1,10,20 Gi0/2 1,10,20

Port Vlans in spanning tree forwarding state and not pruned Gi0/1 1,10,20 Gi0/2 1,10,20

Based on this output, what can be concluded?

A
VLANs 2-9 are allowed but not active on the trunk.
The 'allowed' list includes 1-1005, but only VLANs 1,10,20 are active; thus VLANs 2-9 are allowed but not active (not created in VLAN database).
B
The trunk is using ISL encapsulation.
Why wrong: The encapsulation is shown as 802.1q.
C
VLAN 1 is pruned from the trunk.
Why wrong: VLAN 1 is in the forwarding state, so it is not pruned.
D
Only VLANs 10 and 20 are forwarding traffic.
Why wrong: VLAN 1 is also forwarding.

Question 3mediumdrag order

Drag and drop the steps of STP root bridge election and port state transitions into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 4mediummultiple choice

Examine the following partial Cisco IOS-XE configuration:

interface GigabitEthernet0/1
 switchport mode access
 switchport access vlan 10
 ip access-group ACL_IN in
 spanning-tree portfast

What is the effect of this configuration?

A
The port will immediately transition to forwarding state, reducing STP convergence time for end hosts.
spanning-tree portfast on an access port causes immediate forwarding, as intended for host ports.
B
The port will become a trunk port and participate in VLAN trunking.
Why wrong: The port is configured as an access port, not a trunk.
C
The port will use Rapid PVST+ and immediately forward after a link failure.
Why wrong: PortFast does not change the STP mode; it only affects initial convergence.
D
The port will block all inbound traffic due to the ACL.
Why wrong: The ACL is applied inbound but does not block all traffic; it filters based on the ACL entries.

Question 5mediummatching

Read the full EtherChannel explanation →

Drag and drop each STP variant on the left to its matching IEEE standard on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts

Matches

IEEE 802.1D

IEEE 802.1w

IEEE 802.1s

Cisco proprietary per-VLAN spanning tree

Question 6mediummatching

Drag and drop each EtherChannel port state on the left to its matching description on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts

Matches

Port is part of the channel and forwards traffic

Port is not part of the channel, operates as normal switchport

Port is disabled due to incompatible parameters

Port is in process of negotiation (LACP/PAgP)

Port has been added to the port-channel interface

Question 7mediummultiple choice

Given the following configuration snippet on a Cisco IOS-XE switch:

interface GigabitEthernet1/0/1
 switchport mode access
 switchport access vlan 10
 spanning-tree portfast

monitor session 1 source interface GigabitEthernet1/0/1 both monitor session 1 destination interface GigabitEthernet1/0/2

What is the effect of this configuration?

A
All traffic entering and leaving GigabitEthernet1/0/1 is copied to GigabitEthernet1/0/2.
The 'both' keyword copies both ingress and egress traffic from the source interface to the destination.
B
Only traffic entering GigabitEthernet1/0/1 is copied to GigabitEthernet1/0/2.
Why wrong: The 'both' keyword copies both directions, not just ingress.
C
Traffic on GigabitEthernet1/0/2 is replicated to GigabitEthernet1/0/1.
Why wrong: The monitor session defines source and destination; traffic flows from source to destination, not the reverse.
D
The configuration is invalid because the destination port must be in trunk mode.
Why wrong: A SPAN destination port can be an access port; trunk mode is not required.

Question 8mediumdrag order

Read the full EtherChannel explanation →

Drag and drop the steps for configuring STP root guard and loop guard and the resulting port behavior into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 9mediummatching

Drag and drop each EtherChannel port state on the left to its matching description on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts

Matches

Port is actively forwarding traffic in the EtherChannel

Port is active but not part of any EtherChannel

Port is administratively down or error-disabled in the channel

A
bundled: Port is actively forwarding traffic in the EtherChannel
Correct: This describes a bundled port that actively forwards traffic.
B
stand-alone: Port is active but not part of any EtherChannel
Correct: This describes a stand-alone port that is active but not in a channel.
C
suspended: Port is administratively down or error-disabled in the channel
Correct: This describes a suspended port that is down or error-disabled.
D
bundled: Port is a member of the channel and forwarding
Why wrong: Incorrect: This is a duplicate of the bundled state. While the description is valid, only P1 is the intended match.
E
stand-alone: Port operates as a regular switch port
Why wrong: Incorrect: This is a duplicate of the stand-alone state. While the description is valid, only P2 is the intended match.

Question 10hardmultiple choice

A network engineer is implementing model-driven telemetry on a Cisco Nexus 9000 switch to monitor VLAN and STP changes. The engineer wants to use the native telemetry protocol with UDP as the transport. After configuring the telemetry subscription with the 'destination-group' and 'sensor-group', the engineer notices that the collector is not receiving any data. The collector is reachable and the UDP port is open. What is the most likely missing configuration?

A
The engineer forgot to configure a 'source-interface' under the destination-group
Why wrong: A source-interface is recommended but not mandatory; the switch will use the management interface by default.
B
The engineer did not create a 'policy' that binds the sensor-group and destination-group
On Nexus, a telemetry policy is required to link the sensor and destination groups; without it, no data is streamed.
C
The YANG models for VLAN and STP are not supported in the native telemetry protocol
Why wrong: Nexus supports YANG models for VLAN and STP in the native telemetry protocol.
D
The engineer used GPB encoding instead of JSON, and the collector only accepts JSON
Why wrong: Encoding mismatch would cause parsing issues, but the collector would still receive data; the issue is that no data is received at all.

Question 11mediummulti select

Which three statements about STP topology changes and convergence are true? (Choose three.)

A
A switch that detects a topology change sends a TCN BPDU toward the root bridge.
Correct because the TCN (Topology Change Notification) is sent to inform the root bridge of a change.
B
The root bridge sets the Topology Change (TC) flag in its BPDUs after receiving a TCN.
Correct because the root bridge propagates the TC flag to all switches, triggering MAC table flushing.
C
When the TC flag is set, switches reduce the MAC address aging timer to the forward delay time.
Correct because this flushes stale MAC entries quickly, allowing the network to relearn paths.
D
The Max Age timer is used to flush MAC address entries during a topology change.
Why wrong: Incorrect because Max Age is used to age out BPDU information, not MAC addresses.
E
The forward delay timer determines how long a switch waits before transitioning from listening to learning state.
Why wrong: Incorrect because the forward delay timer applies to both listening and learning states, but it is not directly related to MAC aging during topology changes.

Question 12mediummatching

Drag and drop each STP protection feature on the left to its matching purpose on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts

Matches

Immediately transitions a port to forwarding state

Err-disables a port if a BPDU is received

Prevents a port from becoming the root port

Prevents a port from transitioning to forwarding when BPDUs stop

Question 13mediummulti select

Full question →

Which two statements about Rapid PVST+ are true? (Choose two.)

A
Rapid PVST+ uses a proposal/agreement handshake to achieve rapid convergence.
Correct because the proposal/agreement mechanism allows ports to transition to forwarding quickly without relying on timers.
B
Rapid PVST+ runs a separate instance of STP for each VLAN.
Correct because Rapid PVST+ is per-VLAN, providing independent spanning trees for each VLAN.
C
Rapid PVST+ requires the UplinkFast feature to be enabled for fast uplink convergence.
Why wrong: Incorrect because UplinkFast is a legacy Cisco feature for 802.1D; RSTP inherently provides fast convergence.
D
In Rapid PVST+, the root bridge is elected based on the lowest MAC address only.
Why wrong: Incorrect because the root bridge is elected based on the lowest bridge priority (which includes a configurable priority value and the MAC address as a tiebreaker).
E
Rapid PVST+ supports only two port roles: designated and root.
Why wrong: Incorrect because RSTP defines additional port roles: alternate and backup, in addition to designated and root.

Question 14mediumdrag order

Drag and drop the steps of STP path cost manipulation for load balancing into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 15mediummatching