CCNA Exams

CCNA Exams Answers

CCNA 3 v6.0CCNA ExamsCCNA v6.0

CCNA3 v6.0 Chapter 3 Exam Answers


1. Which two network design features require Spanning Tree Protocol (STP) to ensure correct network operation? (Choose two.)

static default routes
implementing VLANs to contain broadcasts
redundant links between Layer 2 switches*
link-state dynamic routing that provides redundant routes
removing single points of failure with multiple Layer 2 switches*

2. What is the outcome of a Layer 2 broadcast storm?

Routers will take over the forwarding of frames as switches become congested.
New traffic is discarded by the switch because it is unable to be processed.*
CSMA/CD will cause each host to continue transmitting frames.
ARP broadcast requests are returned to the transmitting host.

3. What is the purpose of the Spanning Tree Protocol (STP)?

prevents Layer 2 loops*
prevents routing loops on a router
creates smaller collision domains
creates smaller broadcast domains
allows Cisco devices to exchange routing table updates

4. What is a characteristic of a Layer 2 loop?

Broadcast frames are forwarded back to the sending switch.*
The Time-to-Live attribute of a frame is set to infinity.
Routers continually forward packets to other routers.
A switch is continually forwarding the same unicast frame.

5. What additional information is contained in the 12-bit extended system ID of a BPDU?

MAC address
IP address
port ID

6. Which three components are combined to form a bridge ID?

port ID
IP address
extended system ID*
MAC address*
bridge priority*

7. Refer to the exhibit.

Which switch will be elected the root bridge and which switch will place a port in blocking mode? (Choose two.)

SW1 will become the root bridge.
SW2 will become the root bridge.
SW2 will get a port blocked.
SW4 will get a port blocked.*
SW3 will become the root bridge.*
SW4 will become the root bridge.

8. Refer to the exhibit.

Which trunk link will not forward any traffic after the root bridge election process is complete?


9. Which protocol provides up to 16 instances of RSTP, combines many VLANs with the same physical and logical topology into a common RSTP instance, and provides support for PortFast, BPDU guard, BPDU filter, root guard, and loop guard?

Rapid PVST+

10. Which Cisco switch feature ensures that configured switch edge ports do not cause Layer 2 loops if a port is mistakenly connected to another switch?

BPDU guard*
extended system ID

11. Which two types of spanning tree protocols can cause suboptimal traffic flows because they assume only one spanning-tree instance for the entire bridged network? (Choose two.)

Rapid PVST+

12. Which spanning tree standard supports only one root bridge so that traffic from all VLANs flows over the same path?

Rapid PVST

13. What is an advantage of PVST+?

PVST+ requires fewer CPU cycles for all the switches in the network.
PVST+ reduces bandwidth consumption compared to traditional implementations of STP that use CST.
PVST+ optimizes performance on the network through autoselection of the root bridge.
PVST+ optimizes performance on the network through load sharing.*

14. In which two port states does a switch learn MAC addresses and process BPDUs in a PVST network? (Choose two.)


15. If no bridge priority is configured in PVST, which criteria is considered when electing the root bridge?

lowest IP address
lowest MAC address*
highest IP address
highest MAC address

16. Which RSTP ports are connected to end devices?

trunk ports
designated ports
root ports
edge ports*

17. A network administrator is preparing the implementation of Rapid PVST+ on a production network. How are the Rapid PVST+ link types determined on the switch interfaces?

Link types are determined automatically.*
Link types must be configured with specific port configuration commands.
Link types can only be determined if PortFast has been configured.
Link types can only be configured on access ports configured with a single VLAN.

18. Which port state will switch ports immediately transition to when configured for PortFast?


19. Which STP priority configuration would ensure that a switch would always be the root switch?

spanning-tree vlan 10 priority 0*
spanning-tree vlan 10 priority 61440
spanning-tree vlan 10 root primary
spanning-tree vlan 10 priority 4096

20. Refer to the exhibit.

What is the role of the SW3 switch?

designated switch
edge switch
root bridge*
enabled bridge
local bridge

21. To obtain an overview of the spanning tree status of a switched network, a network engineer issues the show spanning-tree command on a switch. Which two items of information will this command display? (Choose two.)

The root bridge BID.*
The role of the ports in all VLANs.*
The status of native VLAN ports.
The number of broadcasts received on each root port.
The IP address of the management VLAN interface.

22. What port type is used to interconnect switches in a switch stack?


23. Match the spanning-tree feature with the protocol type. (Not all options are used.)

24. Fill in the blank. Do not use abbreviations.

The spanning-tree “mode rapid-pvst” global configuration command is used to enable Rapid PVST+.

25. Open the PT Activity. Perform the tasks in the activity instructions and then answer the question.
Which switch is the root bridge?​