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VLAN Trunking 3

September 16th, 2017 in SWITCH 300-115 Go to comments

Question 1


The “vlan dot1q tag native” command maintains the tagging on the native VLAN and drop untagged traffic -> B is correct.

Reference: http://www.cisco.com/web/techdoc/dc/reference/cli/nxos/commands/l2/vlan_dot1Q_tag_native.html

Question 2

Note: Answer F is not correct because VLAN 600 is the native VLAN on Gi6/2 does not mean untagged traffic is tagged with this VLAN. It only means “all untagged traffic belongs to VLAN 600”.

Question 3

Question 4

Question 5

Question 6


Although Gi0/10 has been configured as trunk it it did not appear in the “show interfaces trunk” command so the most suitable reason is it is down (not administratively down but down for another reason).

Question 7


By entering the command “switch port trunk allowed vlan 2,3,4”, vlan 5 would be removed from allowed VLAN list. Both Workstations A & B are on VLAN 5 so they cannot communicate any more.

Note: If we want to add vlan 2 to 4 to the allowed VLAN list then we should use the “switchport trunk allowed vlan add 2,3,4”.

Question 8

Question 9

Question 10

  1. MaryCisco
    September 19th, 2017

    Why the answer on question 6 is D? I saw the configuration on interface FastEthernet0/2 (sw02) and on interface FastEthernet0/1 (sw01) that allows vlan 5…………….

  2. Nic
    September 21st, 2017

    Read Question carefully.
    it says “the effect of entering the switchport trunk allowed vlan 2,3,4 command”.

  3. WrittingSoon
    September 21st, 2017

    where are the questions?

  4. montu
    October 3rd, 2017

    where can i get latest dumps for CCNP switch
    have an exam in 15 days

  5. Rizwan
    October 10th, 2017

    in q6 if the gi0/10 port is trunk, why it is showing the the show vlan breif command? because in my practical preparation, the links marked as trunk are not shown in the show vlan commands, assist please

  6. switchy
    October 15th, 2017

    Q5 Why is the answer not “A”?

  7. switchy
    October 15th, 2017

    Q6 And Rizwan is right. The interface is showing on show vlan, wouldn’t that mean that the interface is active or up?

  8. swsw
    October 17th, 2017

    The Q4 is correct? The dynamic auto in both sides not will form a trunk port?

  9. superB
    October 19th, 2017

    @swsw – Q4. Dynamic Auto on both sides will form an ACCESS.

    Table 3-8 DTP Negotiated Interface Modes:

    TABLE,Dynamic Auto,Dynamic Desirable,Trunk,Access
    Dynamic Auto,Access,Trunk,Trunk,Access
    Dynamic Desirable,Trunk,Trunk,Trunk,Access
    Trunk,Trunk,Trunk,Trunk,Limited connectivity
    Access,Access,Access,Limited connectivity,Access

  10. switchy
    October 26th, 2017

    Q2 How do I know why the device is configured with the default MST region?

  11. switchy
    October 26th, 2017

    Q4 Should be A and D?

  12. switchy
    October 26th, 2017

    Q5 should be A, D right? O_o?
    B is wrong as it only allows VLAN 915 but not actually tag it with VLAN 915.

  13. switchy
    October 26th, 2017

    Q6 The interface is showing on Vlan 1 on “show vlan”.
    Why the heck is the answer “The interface is down”

  14. superB
    November 1st, 2017

    Q4 – correct answers are B,C. See Table 3-8 for details here, http://www.ciscopress.com/articles/article.asp?p=2181837&seqNum=8

    Q5 – correct answers are B,D. You need to review what “tag traffic” means. :)
    Option A has “switchport mode access”, therefore traffic is not tagged. A PC connected to that switchport will be in vlan 915, but it will never ‘know’ that. So, option A is wrong.
    Option B is correct because – switchport is in trunk mode and all traffic that is NOT NATIVE gets tagged.
    There is “switchport trunk allowed vlan 915” – so traffic on vlan 915 is allowed.
    There is NO “switchport trunk NATIVE vlan 915”. So, traffic on vlan 915 is allowed and tagged.

    In general – If there if you don’t see “switchport trunk NATIVE vlan XYZ” command, then vlan 1 is considered native vlan and traffic on that vlan 1 is NOT tagged.

    Q6 – “show interfaces trunk” has no output, so the interface is down, nothing is connected to that interface. In this case the port is listed under default vlan 1. If the interface is connected to another switch, Gi0/10 will be listed under “show interfaces trunk”, even if the other side is misconfigured.

  15. Stovepipe
    November 10th, 2017

    Q6- Interesting… I could be wrong, but I’m pretty sure the choices that I had were the following 1) The interface is shutdown, 2) the “switchport” command is missing from the configuration, 3) The interface is plugged into an access port on another switch, or 4) the “no shutdown” command is missing from the configuration. So, I am assuming that the best answer in this scenario would be that the interface is “shutdown”?

  16. Mago
    November 13th, 2017

    Is Q2 right?

  17. Anonymous
    November 15th, 2017

    Q6, if A “the interface is down” is correct, shouldn’t D “the interface needs no shutdown configured” be correct as well?

  18. Anonymous
    November 16th, 2017

    For Q6 with the outputs we have you know the interface is down, but you don’t know if its down due to being shut on the switch or on the the other side or even if the cable is broken/disconnect.
    So A “the interface is down” is the best choice in my opinion

  19. Addie
    December 4th, 2017

    What is the ans for question 3????

  20. RA
    December 6th, 2017

    Question 2, how do we know that The device is configured with the default MST region?

  21. ciptech
    December 6th, 2017

    @RA I think because of the last line, you see only all the configured VLANs running under the STP.
    Port —– Vlans in spanning tree forwarding state and not pruned:

  22. Jane
    January 2nd, 2018

    Q6 :: A and D are correct. However, the configuration for int Gi0/10 explicitly shows “no shutdown” is missing. Hence that would make D a better answer, imo

  23. Anonymous
    January 11th, 2018

    Q7 the answer is A. Both reside in Vlan 5 and both switches state ‘switchport trunk allowed vlan 5’

  24. Drj
    January 12th, 2018

    Q7 – i did this lab on pkt tracer… this question is not corret..
    I can ping normaly the pcs, so the correct answer is A

  25. MM
    January 18th, 2018

    about Question 2? Please, how I know that The device is configured with the default MST region? How can I check this information

  26. Doc
    January 30th, 2018

    Same question. Seriously Q2 is correct for MST region? I am not sure but it’s last one answer which could be possible. I not sure if it’s correct or not. Not know how to check but all of the others are invalid. I scheduled my exam for tomorrow so I would receive correct explanation if possible till 11:00 GMT ;-). Or I will believe you :-D

  27. Doc
    January 30th, 2018

    @MM I just received information from colleague which passed test 2w ago. There should be one more answer which is correct. So it is not MST region but something else. :-)

  28. Archangel
    March 1st, 2018

    Question 3 ans may be “D” because switchport encapsulation command missing, hence trunk will not create.

  29. Tinman
    March 11th, 2018

    Q4 – I believe C is wrong. The default switchport mode for newer Cisco switch Ethernet interfaces is dynamic auto. Note that if two Cisco switches are left to the common default setting of auto, a trunk will never form.

  30. Archangel
    March 12th, 2018

    i have problem with frame size of 802.1q, according Wikipedia “The minimum frame size is left unchanged at 64 bytes.[2] The maximum frame size is extended from 1,518 bytes to 1,522 bytes.”

    But according to CISCO Minimum size is “The 802.1Q tag is 4 bytes. Therefore, the resulting Ethernet frame can be as large as 1522 bytes. The minimum size of the Ethernet frame with 802.1Q tagging is 68 bytes. ”

    Please help

  31. Confuse guy
    March 15th, 2018


    Min frame size = 64
    Min frame size when encapsulated by 802.19 = 64 + 4 = 68

  32. Archangel
    March 19th, 2018

    hey, Confuse guy, thanks buddy

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