350-001 Written: Spanning Tree & VTP Part 1

1. Which two are effects of connecting a network segment that is running 802.1D to a network

segment that is running 802.1w? (Choose two.)

A.

The entire network switches to 802.1D and generates BPDUs to determine root bridge status.

B.

comes up.

A migration delay of three seconds occurs when the port that is connected to the 802.1D bridge

C.

bridge for the 802.1w segment, is chosen.

The entire network reconverges and a unique root bridge for the 802.1D segment, and a root

D.

mode and converts the BPDUs to either 802.1D or 802.1w BPDUs to the 802.1D or 802.1w

segments of the network.

The first hop 802.1w switch that is connected to the 802.1D runs entirely in 802.1D compatibility

E.

will not be necessary if point-to-point links and edge ports are properly identified and set by the

administrator.

Classic 802.1D timers, such as forward delay and max-age, will only be used as a backup, and

Answer: B,E

Explanation:
See the details about backwards compatibility on the following URLhttp://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml

2. Which statement is true about TCN propagation?

A.

The originator of the TCN immediately floods this information through the network.

B.

The TCN propagation is a two step process.

C.

A TCN is generated and sent to the root bridge.

D.

The root bridge must flood this information throughout the network.

Answer: A

Explanation:
Under RSTP (802.1W) TCNs are flooded to all ports immediately, without having to wait for the root switch. See the following URL
http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml#prop

3. Which statement is true about loop guard?

A.

Loop guard only operates on interfaces that are considered point-to-point by the spanning tree.

B.

Loop guard only operates on root ports.

C.

Loop guard only operates on designated ports.

D.

Loop guard only operates on edge ports.

Answer: A

Explanation: Not needed. You should know loop guard at this point in your career. You can also reference the "Configuration Considerations" on the following URL.

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080094640.shtml

4. Which two options are contained in a VTP subset advertisement? (Choose two.)

A.

followers field

B.

MD5 digest

C.

VLAN information

D.

sequence number

Answer: C,D

Explanation: "Subset advertisements contain information on the status of the VLAN. They also contain the VLAN type (Ethernet, Token Ring, FDDI, or other), the VLAN name and ID, the MTU, and the SAID value." VTP sequence number is also a referenced field. URL follows:
https://learningnetwork.cisco.com/thread/7181

5. Which three options are features of VTP version 3? (Choose three.)

A.

VTPv3 supports 8K VLANs.B. VTPv3 supports private VLAN mapping.

C.

VTPv3 allows for domain discovery.

D.

VTPv3 uses a primary server concept to avoid configuration revision issues.

E.

VTPv3 is not compatible with VTPv1 or VTPv2.

F.

VTPv3 has a hidden password option.

Answer: B,D,F

Explanation:  Check out the following URL
http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/catos/8.x/configuration/guide/vtp.html#wp1017196

6. Which three options are considered in the spanning-tree decision process? (Choose three.)

A.

lowest root bridge ID

B.

lowest path cost to root bridge

C.

lowest sender bridge ID

D.

highest port ID

E.

highest root bridge ID

F.

highest path cost to root bridge

Answer: A,B,C

Explanation:

7. In 802.1s, how is the VLAN to instance mapping represented in the BPDU?

A.

The VLAN to instance mapping is a normal 16-byte field in the MST BPDU.

B.

The VLAN to instance mapping is a normal 12-byte field in the MST BPDU.

C.

The VLAN to instance mapping is a 16-byte MD5 signature field in the MST BPDU.

D.

The VLAN to instance mapping is a 12-byte MD5 signature field in the MST BPDU.

Answer: C

Explanation: Reference pg. 142 of STD 802.1Q-2005, available here

http://standards.ieee.org/getieee802/download/802.1Q-2005.pdf

8. Users that are connected to switch SWD are complaining about slow performance when they are doing large file transfers from a server connected to switch SWB. All switches are running PVST+. Which option will improve the performance of the file transfers?

A.

Reconnect the clients from switch SWD to switch SWA.

B.

Reconnect the clients from switch SWD to switch SWC.

C.

Change PVST+ to RSTP.

D.

Change the STP root switch from switch SWA to switch SWB.

E.

Configure an EtherChannel between switch SWB and switch SWC.

Answer: D

Explanation: Due to spanning tree operation, the Gigabit link between B and C is not in use for these file transfers. Making switch B the root will activate this link and speed network access for the users on switch D.

9. While you are troubleshooting network performance issues, you notice that a switch is periodically flooding all unicast traffic. Further investigation reveals that periodically the switch is also having spikes in CPU utilization, causing the MAC address table to be flushed and relearned. What is the most likely cause of this issue?

A.

a routing protocol that is flooding updates

B.

a flapping port that is generating BPDUs with the TCN bit set

C.

STP is not running on the switch

D.

a user that is downloading the output of the show-tech command

E.

a corrupted switch CAM table

Answer: B

Explanation: n/a

10. When troubleshooting the issue, you notice the election of a new root bridge with an unknown MAC address. Knowing that all access ports have the PortFast feature enabled, what would be the easiest way to resolve the issue without losing redundant links?

A.

Enable bpduguard globally.

B.

Enable rootguard.

C.

Enable loopguard.

D.

Enable spanning tree.

E.

Enable UDLD.

Answer: A

Explanation: Loopguard, spanning tree, and UDLD are obvious red herrings. This leaves enabling rootguard or bpduguard. One key is that enabling bpduguard only affects ports that have portfast enabled; see the following URL under "Configuration." http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a008009482f.shtml

11. Spanning Tree Protocol IEEE 802.1 s defines the ability to deploy which of these?

A.

one global STP instance for all VLANs

B.

one STP instance for each VLAN

C.

one STP instance per set of VLANs

D.

one STP instance per set of bridgesAnswer: C
Explanation: read the 802.1S document

12. Which two of these are used in the selection of a root bridge in a network utilizing Spanning Tree Protocol IEEE 802.1 D? (Choose two.)

A.

Designated Root Cost

B.

bridge ID priority

C.

max age

D.

bridge ID MAC address

E.

Designated Root PriorityF.
Answer: B,D
Explanation: read the 802.1D IEEE document

13. If a port configured with STP loop guard stops receiving BPDUs, the port will be put into which state?

A.

learning state

B.

listening state

C.

forwarding state

D.

loop-inconsistent stateAnswer: D
Explanation: http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080094640.shtml

14. What is the purpose of the STP PortFast BPDU guard feature?

A.

enforce the placement of the root bridge in the network

B.

ensure that a port is transitioned to a forwarding state quickly if a BPDU is received

C.

enforce the borders of an STP domain

D.

ensure that any BPDUs received are forwarded into the STP domainAnswer: C
Explanation: http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a008009482f.shtml#topic1

15. When STP UplinkFast is enabled on a switch utilizing the default bridge priority, what will the new bridge priority be changed to?

A.

8192

B.

16384

C.

49152

D.

65535Answer: C
Explanation: http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080094641.shtml#cfg_upling_fast

16. Which of these best describes the actions taken when a VTP message is received on a switch configured with the VTP mode "transparent"?A.

B.

VTP updates are ignored and forwarded out trunks only.

C.

VTP updates are made to the VLAN database and are forwarded out trunks only.

D.

VTP updates are ignored and are not forwarded.Answer: B
Explanation: "In VTP version 2, transparent switches do forward VTP advertisements that they receive from other switches from their trunk interfaces."
http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_13_ea1/configuration/guide/swvtp.html

17. The classic Spanning Tree Protocol (802.1 D 1998) uses which sequence of variables to determine the best received BPDU?

A.

1) lowest root bridge id, 2) lowest sender bridge id, 3) lowest port id, 4) lowest root path cost

B.

1) lowest root path cost, 2) lowest root bridge id, 3) lowest sender bridge id, 4) lowest sender port id

C.

1) lowest root bridge id, 2) lowest sender bridge id, 3) lowest root path cost 4) lowest sender port id

D.

1) lowest root bridge id, 2) lowest root path cost, 3) lowest sender bridge id, 4) lowest sender port idAnswer: D
Explanation: https://learningnetwork.cisco.com/thread/7653

18. Which three port states are used by RSTP 802.1w? (Choose three.)

A.

Listening

B.

Learning

C.

Forwarding

D.

Blocking

E.

Discarding

F.

DisabledAnswer: B,C,E
Explanation: http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml#states

19. Refer to the exhibit above. Catalyst R is the root bridge for both VLAN 1 and VLAN 2. What is the easiest way to load-share traffic across both trunks and maintain redundancy in case a link fails, without using any type of EtherChannel link-bundling?

A.

Catalyst D so that port D2 becomes the root port on Catalyst D for VLAN 2.

Increase the root bridge priority (increasing the numerical priority number) for VLAN 2 on

B.

Decrease the port priority on R2 for VLAN 2 on Catalyst R so that port D1 will be blocked for VLAN 2 and port D2 will remain blocked for VLAN 1.

C.

VLAN 2 and port D2 will remain blocked for VLAN 1.

Decrease the path cost on R2 on Catalyst R for VLAN 2 so that port D1 will be blocked for

D.

Catalyst R so that R2 becomes the root port on Catalyst D for VLAN 2.

Increase the root bridge priority (decreasing the numerical priority number) for VLAN 2 onAnswer: B
Explanation: http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800ae96a.shtml