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VTPv3 Sim

October 11th, 2018 in Lab Sim Go to comments

You have been asked to install and configure a new switch in a customer network. Use the console access to the existing and new switches to configure and verify correct device configuration.


Question 1


To comply with the configuration of other switches, we need to get VTP configuration of Sw1 or Sw2. On Sw1 use the “show vtp status” command:


From this output we learn on Sw1:
+ VTP is running version 3
+ VTP Domain is “CCNP”
+ Sw1 is the VTP Primary Server (we will explain about Primary Server later. Now just understand it is in VTP Server mode)

So on the New_Switch, the VTP Domain must match. New_Switch should run VTP version 3 if if can (but it is not a must as VTP version 2 is compatible with VTP version 3). The New_Switch is connecting to hosts so it is in Access Layer so it should be configured as a VTP Client (although Transparent mode is acceptable) so there are only two suitable choices D & E.

From the exhibit, the New_Switch is connecting to a host in VLAN 100 so its E0/0 interface should be in VLAN 100 -> only D is correct.

Question 2


On Sw1 & Sw2 we can check with the “show interfaces trunk” command:



Sw1 & Sw2 are connected through E2/3 & E2/3 so we can see the native Vlan on these trunks are 99. We should check both Sw1 & Sw2 to see if the Native Vlan on both sides match.

Question 3


Use the “show vtp status” on SW1 and SW2 we notice both of them are in “Server” mode so we should choose: A. Configure VLAN 500 & VLAN 600 on both SW1 & SW2.

In practical we only need to create VLANs on one of the “Server” switch and these VLANs will be propagated automatically to others “Server” and “Client” switch. But maybe it is not the answer Cisco wants (as it makes both answers B & C are correct).

Question 4


To configure private VLAN we have to change VTP (even version 3) to Transparent mode. In fact, to disable VTP pruning on Sw4 (in Client mode) we also have to change to VTP Transparent mode so answer C can be understood as “change SW4 to Transparent mode” so it is the best choice.

Note: Unlike VTP version 1 and 2 in which VTP pruning is enabled on VTP Server only, VTP version 3 requires VTP pruning must be enabled on all the switches in the VTP domain so we can also disable VTP pruning on each switch separately. Here is the link for your reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_55_se/configuration/guide/3750xscg/swvtp.html

“With VTP versions 1 and 2, when you enable pruning on the VTP server, it is enabled for the entire VTP domain. In VTP version 3, you must manually enable pruning on each switch in the domain.”

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  1. suntzu
    January 11th, 2020

    8th, 2020

    The only issue with picking SW 4 is that it says to PICK SW4 ONLY and disable pruning. SW4 is a client. So, by disabling VTP on sw4, it would not accept the VLAN propagation either way. Unless this question left out some of the answer, it is still just disable pruning on SW1. Because with that, you don’t have to do anything ELSE since sw1 is primary. And, the other switches do not matter because the question is asking about SW4 ONLY.

    The real answer should be
    create vlans on primary, disable pruning
    change sw4 to transparent and disable pruning. SW4 does not have to have the VLANS, it just needs to pass the advertisements.

  2. Syn
    January 12th, 2020

    @suntzu, unfortunately, nothing has been left out of the question, this is the entire question so it is pretty confusing.
    VTPv3 requires pruning to be configured per switch manually, so if we disable it on SW1 and then configure private VLANs on it, they should be propagated to SW4 as it is a client. However, SW4 will not work with private VLANs if pruning is enabled there, so it should be disabled there as well.
    Since the entire question is about VTPv3 and VTPv3 supports private VLANs in server and client mode as well, as opposed to the other two versions, i don’t think they consider Transparent mode as a factor here.

    Here’s on thing i didn’t think of during the exam, maybe the pruning status on one of these two switches is already disabled in the lab there and they expect you to respond with the one on which it isn’t alread disabled. Whoever attempts the exam next should try to run show vtp status on both switches in the exam to check if that’s the case.

  3. Syn
    January 12th, 2020

    @JG: no disabling pruning does not change the operation mode of the switch, and with VTPv3, pruning is only effective on the local switch even if you apply it on the server.

    Also, in the exam, none of the switches had any indication of being a primary switch. And VTPv3 only allows VLAN configuration to be done on primary server switch, all other servers just function as clients with the possibility to be promoted if required.

  4. Saji
    January 12th, 2020

    !!!!!u don’t need to disable the pruning on SW4. !!!!!
    If u create PVLAN on SW1 (which is primary )will be passed into client(SW4) whose vtp version is
    3 and pruning is ON.
    I lab it. IF you wan to create PVLAN locally then only u must disable the pruning.
    So answer is A.

  5. Maz
    January 13th, 2020

    Does this Sim require any configuration or just the output of the show commands to get the answers?

  6. Syn
    January 13th, 2020

    @Maz just show commands

  7. fake
    January 17th, 2020

    all answers are correct

  8. @fake
    January 17th, 2020

    How do you know that? VTPv3 can only have one primary server and in this example it’s Sw1. Therefore you cannot configure anything on Sw2. Therefore the answer “A. Configure VLAN 500 & VLAN 600 on both SW1 & SW2” is incorrect.

    I know Cisco can be tricky on their exams but consider this from the answer section:

    “In practical we only need to create VLANs on one of the “Server” switch and these VLANs will be propagated automatically to others “Server” and “Client” switch. But maybe it is not the answer Cisco wants (as it makes both answers B & C are correct).”

    Except Certprepare are ignoring the VTPv3 primary server restriction. Additionally, Cisco isn’t going to give 3 correct answers on this question and hope we pick the “more” correct one. As Sw1 is a VTPv3 primary server, and therefore the only switch you can configure on, the following answer must be the right one:

    “B. Configure VLAN 500 and VLAN 600 on SW1 only”

    If not explain why I’m wrong.

  9. Question 3
    January 18th, 2020

    @fake I agree with you anyone took exam could feedback us?

  10. Anonymous
    January 18th, 2020

    But the question does not say CREATE VLAN!!!!
    It is saying your “You are adding new VLANs.” meaning vlans are already added (that is done for you ) trough sw1(primary) and you are asked how you will CONFIGURE this so “SW1 as primary root for VLAN 500 and secondary for VLAN 600 and SW2 as primary root for VLAN 600 and secondary for VLAN 500”
    So answer is correct to make one primary for one of the vlans and one primary for the second vlan you will need to configure them on BOTH SW1 and SW2
    Answer is correct !!!

  11. Anonymous
    January 18th, 2020

    What about pruning any conclusions?

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