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ICND2 – STP

May 1st, 2015 in ICND2 200-101 Go to comments

Note: If you are not sure about Spanning Tree Protocol, please read my Spanning Tree Protocol STP tutorial (Premium tutorial).

Question 1

Explanation

Spanning Tree Protocol convergence (Layer 2 convergence) happens when bridges and switches have transitioned to either the forwarding or blocking state. When layer 2 is converged, root bridge is elected and all port roles (Root, Designated and Non-Designated) in all switches are selected.

Question 2

Question 3

Explanation

First, the question asks what switch services the printers, so it can be Switch 3 or Switch 4 which is connected directly to the Printers.

Next, by comparing the MAC address of Switch 3 and Switch 4 we found that the MAC of Switch 3 is smaller. Therefore the interface connected to the Printers of Switch 3 will become designated interface and the interface of Switch 4 will be blocked.
(Please notice that Switch 1 will become the root bridge because of its lowest priority, not Switch 3)

Question 4

Explanation

Per VLAN Spanning Tree (PVST) maintains a spanning tree instance for each VLAN configured in the network. It means a switch can be the root bridge of a VLAN while another switch can be the root bridge of other VLANs in a common topology. For example, Switch 1 can be the root bridge for Voice data while Switch 2 can be the root bridge for Video data. If designed correctly, it can optimize the network traffic.

Question 5

Explanation

PVST+ is based on IEEE802.1D Spanning Tree Protocol (STP). But PVST+ has only 3 port states (discarding, learning and forwarding) while STP has 5 port states (blocking, listening, learning, forwarding and disabled). So discarding is a new port state in PVST+.

Comments (60) Comments
  1. Marc
    November 12th, 2013

    Could you please provide some explanations in regards to Question 2? As far I can see the cost is the same. I don’t get it.

  2. Anonymous
    November 12th, 2013

    Marc,

    The port role is Alternate meaning that another switch port in the network had lower cost path for vlan2. From the output all you can tell is that the switch shown is not the root for that vlan and its cost is 19 meaning another port had a cost of 18 or lower. Potentially also could have another port with a cost of 19, but had a lower MAC address of the switch.

  3. Saivivek
    December 26th, 2013

    Can you please provide the diagram for Q2.

  4. Anonymous
    January 17th, 2014

    Q2.I thought it was D. but reading carefully, if the local switch had a lower Bridge ID than the elected designated switch then the output will show all ports role as Designated Ports implying that “This is the root bridge” but it is not the root bridge because the output shows Root Port roles how to get to the actual root bridge. Now C makes more sense, the key word in C. is “Path” remember the local switch adds cost in the path to get to the root bridge.

  5. Anon
    January 25th, 2014

    Regarding Q #2:

    The switch has already selected it’s Forwarding Ports. Because it has ALREADY selected them must mean that FA0/10 must have a higher cost value.

  6. D
    February 7th, 2014

    Marc,

    Since the priority of both switches are equal then the mac address breaks the tie. Compare each digit of both mac addresses until the one with the lowest digit wins. xxxx.xxxx.xxxx.733a (SW3) and xxxx.xxxx.xxxx.7347 (SW4) are equal until the 3rd digit in the final set. SW3’s 3 is lower than SW4’s 4 so SW3’s port will have a lower cost. SW3 becomes the designated port and SW4 is blocked.

  7. D
    February 7th, 2014

    Correction: xxxx.xxxx.733a (SW3) and xxxx.xxxx.7347 (SW4)

  8. Jack
    February 9th, 2014

    The key to question 2 is that it is the output for the command
    show spanning-tree interface fa0/10

    Under Per VLAN STP this interface has a state for every STP instance listed by VLAN

    A. This switch has more than one interface connected to the root network segment in VLAN 2. Not the answer. This switch may not even be directly connected to the root segment.

    B. This switch is running RSTP while the elected designated switch is running 802.1d Spanning Tree. Not the answer, RSTP is designed to work with STP.

    C. This switch interface has a higher path cost to the root bridge than another in the topology. This would cause the port to be blocked.

    D. This switch has a lower bridge ID for VLAN 2 than the elected designated switch. Not the answer because a designated switch by definition would have a lower root cost than the current switch, making BID irrelevant.

    So C is the only thing that qualifies as an explanation for the blocking result in the output.

  9. fuad
    February 12th, 2014

    Hi i just took the test today and failed with a 820. The reason why is because of all the rstp questions they asked me. Can you please post up more rstp questions please.but everything else was good help.

  10. mike
    April 14th, 2014

    Took ICND2 earlier today, 986 / 1000.

    All 5 questions form this page were on there.

    Many thanks 9tut!

  11. TBF
    April 17th, 2014

    Mike anything else to share us ?
    I going to take it may be next month.

  12. Atif
    April 17th, 2014

    MIke I want to know about LAB – 23 April i am having exam

  13. Justin
    April 22nd, 2014

    Mike, I third this question – I am taking the test in less than two days, I appreciate your feedback on all the pages I have seen 🙂 I will surely provide mine when I finish.

    Share anything you can about any subject 😀

    I’ve memorized Nada’s dump along with every question and explanation on 9tut. I am only doing the ICND2 to re-certify my CCNA but I have an obsession with making myself over confident.

  14. mike
    April 23rd, 2014

    Hi Justin. see my note towards the bottom of the “share your ICND2 experiences” page.

    basically this site is hugely helpful, but you will definitely also need a book and i would recommend downloading some past exam questions using examcollection.com. You will need to pay £20 for the s/w to view those exams but it’s well worth it imho.

  15. Justin
    April 24th, 2014

    Thank you for your response!

    I’ve been practicing heavily in using Exam Collection (Nada 120q), 9tut, CBT Nuggets (Jeremy Cioara – Amazing videos btw!) and Packet Tracer to memorize commands and configurations requirements. I feel like I have memorized every question and understand the reasoning for it. (Cisco has their lovely way of making every word count)

    I meant to take the test today I had some non-sense come up that took me away for the day. I will take the test Mon. or Tues. now. (4/28/2014 or 4/29.2014)

    I am only doing the ICND2 to recertify my CCNA. I also took a year long CCNA Cisco Academy class (in 2011) and things are coming back to me pretty quick. But since I took the 640-802 and I remember hearing the ICND2 was a bit more in depth than the CCNA. But shorter And without a Cisco instructor breathing down my back telling me what I am missing I feel like I have to do the breathing lol.

    Anywho, I will report back when I finish my test. Thank you for the input!

  16. Justin
    April 30th, 2014

    Took the test and passed yesterday 986/1000!

    All 5 questions from this page were on there

  17. Damo
    May 20th, 2014

    Q2 answer A… If this switch had two connections to the “root network segment in VLAN2”, and the other port which was connected was f0/9 or lower, wouldn’t the lower port be the root port and forwarding and f0/10 be alternate port and blocking?

  18. izzarazzu
    June 27th, 2014

    Took the exam today. Pass 986/1000. Q1, Q2, Q3, Q4, Q5 were on there.
    Thanks 9tut.

  19. Ant
    August 20th, 2014

    Tested today, 8/20. All 5 of these were on there. Lots of spanning tree questions!

  20. BrOwNiEee
    August 22nd, 2014

    I did my ICND 2 exam today. They asked a lot questions regarding RSTP, none of these questions are mentioned in here. I didn’t remember the questions so sorry for that. i would say studie RSTP aswell before taking the exam.

    Thanks 9tut

  21. Georges
    September 27th, 2014

    took the exam today and pass with 907. Question 1 through 5 were on there.

    location United States Florida.

    test ICND 2

    Thanks 9tut

  22. N8
    September 30th, 2014

    Took ICND2 today 986/100. All of these were on there. Thanks 9TUT

  23. mbrandon32
    October 30th, 2014

    Failed today. 801/1000. A lot of RSTP questions that weren’t covered here.

  24. PaZ
    November 14th, 2014

    Hi Guyz!
    Because people are saying that there are more questions about STP and RSTP, does anyone know where can we find them !?

    Thank you very much!

  25. David
    November 15th, 2014

    Can you update the link for the Spanning-tree-protocol guide?

  26. E-man
    November 29th, 2014

    The question, answer and explanation for #5 don’t really seem to match. Could you look at those again? 🙂

    Thanks!

  27. Gabbie
    December 15th, 2014

    can someone advise about the RSTP ? I see no questions on 9tut but I believe there will be some?

  28. RSTP
    December 18th, 2014

    I jsut came back from the exam. there is some STP but the majority of my LAN questions were RSTP. The image above with the distribution access and core layer was present but in RSTP instead of STP. Know your RSTP ports States, RSTP Root Election and which ports would be blocked during an RSTP convergence where the cost paths are unequal

  29. Jp
    December 21st, 2014

    Q3 on my exam today

  30. M e
    December 29th, 2014

    Hi The link to ‘Spanning Tree Protocol STP tutorial’ isn’t working.

  31. anonny
    February 5th, 2015

    for those complaining of additional RSTP qs

    Check the CCNA site
    not ideal but I am fairly confident they or at leat the theory will be coverd there.

  32. dwh
    March 13th, 2015

    Does the site have the latest CCNA test questions?

  33. barney
    March 20th, 2015

    passed on 3/13. questions 1,2,3 and 5 on there. tks 9tut

  34. meh
    May 2nd, 2015

    Study STP and RSTP!! there were more questions than are listed on here. Specifically the election processes. I still passed, but was very close to failing. You have been warned!

  35. Rich
    May 4th, 2015

    ditto meh’s comment

    The CCNA page has the correct questions for STP/RSTP on ICND2. 9Tut should copy those Q’s to the ICND2 page.

  36. Marco
    May 6th, 2015

    3 comments saying that you got 986/1000? n8, izzarazzu, mike…
    Isn’it strange?

  37. Marco
    May 13th, 2015

    I got all of those questions today in my ICND2 exam.
    Q1, Q2, Q3, Q4, Q5.
    Thanks 9tut.

  38. Yeti
    May 15th, 2015

    Ditto Richs comment above. Check the RSTP questions on the CCNA page.

  39. ttn
    May 16th, 2015

    Q1,2,3,4,5 today ICND2

  40. mike
    June 14th, 2015

    Is any body took the test in jun?

  41. Bobby Chilson
    June 17th, 2015

    Taking the test next Friday June 26th. I’ve used the Lammle book, CBT Nuggets, and this site. Will report back when test is complete.

  42. mike
    June 20th, 2015

    great bobby ,we are waiting for your report back

  43. Grisha82
    June 22nd, 2015

    Got Q3. The same picture and settings. Like print-screen.

  44. Bobby Chilson
    June 26th, 2015

    Passed today with a 986. Had the eigrp and OSPF sim. 95% of the questions were from 9tut. There were at least 2 that I had not seen. Good luck to all.

  45. Anonymous
    June 26th, 2015

    get dumps with nuggets free from this following link
    wurl. cc/dumps

  46. Ghost
    July 1st, 2015

    Passed ICND2 today all question was from 9tut and Nada dump.

  47. Anne Normous
    July 1st, 2015

    Just took the test today – 980/1000 ALL 5 questions were from this page. Thanks 9tuts! Also got Frame Relay, EIGRP and OSPF labs

    THERE IS NO NEED FOR ANY DUMPS – just study one book (Wendel or Todd) and the you tube lessons available free for visual knowledge. Along with 9tuts these are enough for 900 and over marks with ease.

    But you MUST understand the concepts and not mug up the answer as they change the options and answers

  48. Dominic
    July 10th, 2015

    Why the questions are gone?

  49. TOMM3KE
    July 10th, 2015

    Is it normal I can’t view the questions?

  50. Lobo
    July 13th, 2015

    Hey where are the question?

  51. 9tut
    July 13th, 2015

    @all: We had to move all the questions and answers out of 9tut. We can only keep the explanation. You can download the questions and answers at: https://mega.co.nz/#!oIdESYbD!yyu33vygrfKPy4rcmcbV6qW2fxINNoTokuDM3CjA_og

  52. Norm
    July 17th, 2015

    @9tut, with that said, what happens if you paid

  53. 9tut
    July 18th, 2015

    @Norm: Currently the questions are still available for premium members. But we will move them in the future.

  54. Net_G
    July 24th, 2015

    @9tut Is there a timeframe for when the questions will be moved for premium members? Will we still have access to the labs? If the answer is yes, then it’s definitely still worth the $9. Keep up the great work.

  55. Safa
    August 21st, 2015

    I can’t open the STP Tutorial, I received a message says the website has been updated and I should go back to homepage but the link is not working! any advice?

  56. Andreina
    August 21st, 2015

    I can’t see the questions in this page, what is the problem? is that normal? is good to read the explanations but I would like to have the questions

  57. Train
    August 22nd, 2015

    @Safa: We have just fixed that link. Please try again.

    @Andreina: We had to move all the questions and answers out of 9tut because of copyrighted issues. We can only keep the explanation. You can download the questions and answers at: https://mega.co.nz/#!oIdESYbD!yyu33vygrfKPy4rcmcbV6qW2fxINNoTokuDM3CjA_og

  58. Safa
    August 23rd, 2015

    Thanks Train 🙂

  59. MIKE
    May 12th, 2016

    Q1 TO 5 WAS TODAY AT MY EXAM …. 986/1000

  60. M & M
    September 18th, 2016

    http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/5234-5.html

    Explanation from the Cisco Site:
    http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/5234-5.html
    show spantree vlan_id —Shows the current state of the spanning tree for this VLAN ID, from the perspective of the switch on which you issue the command.
    Issue the show spantree vlan_id command in order to verify that Switch 15 is the root of all the appropriate VLANs.
    • From the output from this command, compare the MAC address of the switch that is the root switch to the MAC address of the switch from which you issued the command. If the addresses match, the switch that you are in is the root switch of the VLAN.
    • A root port that is 1/0 also indicates that you are at the root switch.

    This is the sample command output:
    Switch-15> (enable)show spantree 1
    VLAN 1
    spanning-tree enabled
    spanning-tree type ieee

    Designated Root 00-10-0d-b1-78-00

    !— This is the MAC address of the root switch for VLAN 1.

    Designated Root Priority 8192
    Designated Root Cost 0
    Designated Root Port 1/0
    Root Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec

    Bridge ID MAC ADDR 00-10-0d-b1-78-00
    Bridge ID Priority 8192
    Bridge Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec
    This output shows that Switch 15 is the designated root on the spanning tree for VLAN 1.
    • The MAC address of the designated root switch, 00-10-0d-b1-78-00, is the same as the bridge ID MAC address of Switch 15, 00-10-0d-b1-78-00.
    • Another indicator that this switch is the designated root is that the designated root port is 1/0.

    In this output from Switch 12, the switch recognizes Switch 15 as the Designated Root for VLAN 1:
    Switch-12> (enable)show spantree 1
    VLAN 1
    spanning-tree enabled
    spanning-tree type IEEE

    Designated Root 00-10-0d-b1-78-00

    !— This is the MAC address of the root switch for VLAN 1.

    Designated Root Priority 8192
    Designated Root Cost 19
    Designated Root Port 2/3
    Root Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec

    Bridge ID MAC ADDR 00-10-0d-b2-8c-00
    Bridge ID Priority 32768
    Bridge Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec
    Note: The output of the show spantree vlan_id command for the other switches and VLANs can also indicate that Switch 15 is the designated root for all VLANs.