Discontinuing Blog

Unfortunately, the Blogspot system continues to have "problems" that I have no time or ability to resolve. Namely, when I create medium to large sized posts, they are truncated and/or information drops out or is randomly rearranged. This not only upsets me, it makes it impossible to organize and publish a blog!

As of today, I am discontinuing the use of Blogspot for my CCIE studies.

350-001 Written: Spanning Tree & VTP Part 3

1. Refer to the exhibit above. The Layer 2 network uses VTP to manage its VLAN database. A network designer created all VLANs on the VTP server (switch 1) and it has been advertised through VTP to all other VTP clients (switches 2 through 4). Due to network growth, a network operator decided to add a new switch between switch 1 and switch 3. The network operator has been instructed to use a refurbished switch and make it a VTP client. Which three of these factors should the network operator consider to minimize the impact of adding a new switch? (Choose three)

A. Pay special attention to the VTP revision number, because the higher value takes the priority

B. Configure all VLANs manually on the new switch in order to avoid connectivity issuesC. A trunk should be established between the new switch and switches 1 and 3 as VTP only runs over trunk links.
D. Set at least the VTP domain name and password to get the new switch synchronized

E. An ISL trunk should be established between the new switch and switches 1 and 3, because VTP only runs over ISL

F. Pay special attention to the VTP revision number, because the lower value takes the priorityAnswer: A,C,D
Explanation: http://www.cisco.com/en/US/tech/tk389/tk689/technologies_configuration_example09186a0080890607.shtml#conf

2. Before inserting a new switch in the network, the network administrator checks that the VTP domain name is correct, the VTP mode is set to server, and revision is lower than the switches in the network. The administrator then configures interfaces and trunks, erases existing VLANs, and connects the switch to the network. Following that procedure, there is no connectivity in the network. What is a possible cause of this problem?

A. Because the configuration revision of the new switches is lower than the rest of the network, it can change the VLAN database of the other switches

B. As a VTP server, the new switch deleted all VLANs of the network

C. Erasing VLANs increases the VTP configuration revision

D. Since the configuration revision of the network is higher than the new switch, the VLANAnswer: C
Explanation: This answer is directly implied by the following URL on troubleshooting the VTP config revision numberhttp://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080890613.shtml#topic14

3. Network A has a spanning-tree problem in which the traffic is selecting a longer path. How is the path cost calculated? number of hops priority of the bridge interface bandwidth interface delay None of the above
database was automatically synchronized.

A. number of hops

B. priority of the bridge

C. interface bandwidth

D. interface delay

E. None of the aboveAnswer: C
Explanation: reference previous STP questions where interface bandwidth was the answer for path cost.

4. You deployed new fibers in your network to replace copper spans that were too long. While reconnecting the network, you experienced network problems because you reconnected wrong fibers to wrong ports. What could you do to prevent this type of problem in the future, particularly when connecting and reconnecting fiber pairs?

A. Only use fiber in pairs

B. Configure root guard on your switches

C. Do not use fiber but use copper

D. Configure UDLD to prevent one-way link conditionsAnswer: D
Explanation: http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_19_ea1/configuration/guide/swudld.html#wp1020819

5. While deploying a new switch, you accidentally connect ports 3/12 and 3/18 together, creating a loop. STP detected it and placed port 3/18 in blocking mode. Why did STP not place port 3/12 in blocking mode instead?

A. Port 3/12 was already up and forwarding before the loop was created

B. Port priority is based on lowest priority and lowest port number

C. You connected the wire on port 3/18 last

D. None of the above, it is purely random

Answer: B

Explanation: "If all ports have the same priority value, the port with the lowest port number forwards frames." from the following URL http://www.cisco.com/en/US/docs/switches/lan/catalyst4000/7.4/configuration/guide/spantree.html#wp1138416

6. Prior to 802.1w, Cisco implemented a number of proprietary enhancements to 802.1D to improve convergence in a Layer 2 network. Which statement is correct?

A. Only UplinkFast and BackboneFast are specified in 802.1w; PortFast must be manually configured

B. Only PortFast is specified in 802.1w; UplinkFast and BackboneFast must be manually configured.
C. None of the proprietary Cisco enhancements are specified in 802.1w. PortFast, UplinkFast, and BackboneFast are specified in 802.1w.

D. PortFast, UplinkFast, and BackboneFast are specified in 802.1w

Answer: D

Explanation: see the 802.1w RSTP specifications at the URL belowhttp://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml#intro

7. As a network administrator, can you tell me what the root guard feature provides in a bridged network?

A. It ensures that BPDUs sent by the root bridge are forwarded in a timely manner

B. It enforces the root bridge placement in the networkC. It ensures that all ports receiving BPDUs from the root bridge are in the forwarding state
D. It ensures that the bridge is elected as root bridge in the network

Answer: B

Explanation: http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800ae96b.shtml#feature

8. If a Cisco switch is configured with VTPv1 in transparent mode, what is done with received VTP advertisements?

A. They are discarded

B. The contents are altered to reflect the switch's own VTP database and then they are forward
out all trunking ports

C. The changes within the advertisements are made to the switch's VTP databaseD. The contents are ignored and they are forwarded out all trunking ports.
Answer: A

Explanation: "However, in VTP version 2, transparent switches do forward VTP advertisements that they receive from other switches from their trunk interfaces" fromhttp://www.cisco.com/en/US/docs/switches/lan/catalyst2950/software/release/12.1_9_ea1/configuration/guide/swvtp.html


9. Refer to the following descriptions, which three are true about Cisco spanning-tree features? (Choose three)

A. RPVST+ converges faster than RSTP during a topology change

B. STP BPDUs are relayed by all non-root bridges and RSTP BPDUs are generated by each bridge.

C. RSTP can only achieve rapid transition to Forwarding on edge ports and on point-to-point links

D. RPVST+ and RSTP are both based upon the IEEE 802.1w specification.

Answer: B,C,D

Explanation: some helpful RPVST+ info can be found athttp://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example09186a00807b0670.shtml

10. When two bridges are competing for the root bridge of an IEEE 802.1D spanning tree and both have the same bridge priority configured, which parameter determines the winner?

A. highest-numbered IP interface

B. MAC address

C. device uptime
D. root port cost

Answer: B

Explanation: know your 802.1D

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