Spanning Tree practice questions

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 2mediummultiple choice

spanning-tree mode rapid-pvst

What is the effect of this global configuration command?

Trap 1: The switch will use MSTP for all VLANs.

MSTP is configured with 'spanning-tree mode mst'.

Trap 2: The switch will use classic STP for all VLANs.

Classic STP is 'spanning-tree mode pvst'.

Trap 3: The switch will disable STP on all ports.

STP remains enabled; only the mode changes.

A
The switch will use Rapid PVST+ for all VLANs, providing faster convergence than classic STP.
Rapid PVST+ is the Cisco implementation of RSTP per VLAN.
B
The switch will use MSTP for all VLANs.
Why wrong: MSTP is configured with 'spanning-tree mode mst'.
C
The switch will use classic STP for all VLANs.
Why wrong: Classic STP is 'spanning-tree mode pvst'.
D
The switch will disable STP on all ports.
Why wrong: STP remains enabled; only the mode changes.

Open the full VLAN trunking answer →

Question 3mediummultiple 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?

Trap 1: The port will become a trunk port and participate in VLAN trunking.

The port is configured as an access port, not a trunk.

Trap 2: The port will use Rapid PVST+ and immediately forward after a link…

PortFast does not change the STP mode; it only affects initial convergence.

Trap 3: The port will block all inbound traffic due to the ACL.

The ACL is applied inbound but does not block all traffic; it filters based on the ACL entries.

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 4mediumdrag order

Drag and drop the steps of MSTP region and instance configuration steps 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

A
Enter MST configuration mode
Enter MST configuration mode, which is the second step after enabling MST globally.
B
Assign region name
Assign the region name within MST configuration mode, the third step.
C
Set revision number
Set the revision number, typically the fourth step after naming the region.
D
Map VLANs to MST instance
Map VLANs to MST instances, the final configuration step before exiting MST configuration mode.
E
Set spanning-tree mode mst globally
Set spanning-tree mode mst globally – this must be done first to enable MSTP on the switch.

Open the full VLAN trunking answer →

Question 5mediummultiple 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?

Trap 1: Only traffic entering GigabitEthernet1/0/1 is copied to…

The 'both' keyword copies both directions, not just ingress.

Trap 2: Traffic on GigabitEthernet1/0/2 is replicated to…

The monitor session defines source and destination; traffic flows from source to destination, not the reverse.

Trap 3: The configuration is invalid because the destination port must be…

A SPAN destination port can be an access port; trunk mode is not required.

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 6mediumdrag order

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 7mediumdrag 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 8hardmulti select

Which three statements about Multiple Spanning Tree Protocol (MSTP) are true? (Choose three.)

Trap 1: MSTP automatically load-balances traffic across all available…

Incorrect. MSTP does not automatically load-balance; you must manually map VLANs to different instances to achieve load balancing.

Trap 2: MSTP requires a separate root bridge to be elected for each VLAN in…

Incorrect. In MSTP, a root bridge is elected per MST instance, not per VLAN. Multiple VLANs share the same root within an instance.

A
MSTP allows multiple VLANs to be grouped into a single spanning-tree instance, reducing CPU and memory usage.
Correct. This is the primary benefit of MSTP: mapping many VLANs to fewer STP instances.
B
In MSTP, the Internal Spanning Tree (IST) instance is instance 0 and is always present in every MST region.
Correct. IST (instance 0) is mandatory and provides connectivity within the region and to other regions.
C
MSTP requires that all switches in the same MST region have the same VLAN-to-instance mapping, revision number, and region name.
Correct. These three parameters define an MST region; mismatches cause switches to treat each other as separate regions.
D
MSTP automatically load-balances traffic across all available uplinks without any configuration.
Why wrong: Incorrect. MSTP does not automatically load-balance; you must manually map VLANs to different instances to achieve load balancing.
E
MSTP requires a separate root bridge to be elected for each VLAN in the network.
Why wrong: Incorrect. In MSTP, a root bridge is elected per MST instance, not per VLAN. Multiple VLANs share the same root within an instance.

Question 9mediumdrag order