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VLAN Questions

November 24th, 2018 in SWITCH 300-115 Go to comments

Question 1

Explanation

The Port Fast feature is automatically enabled when voice VLAN is configured. When you disable voice VLAN, the Port Fast feature is not automatically disabled.

Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3550/software/release/12-1_19_ea1/configuration/guide/3550scg/swvoip.html

Question 2

Explanation

802.1Q VLAN frames are distinguished from ordinary Ethernet frames by the insertion of a 4-byte VLAN tag into the Ethernet header.

802.1q_header.png

Question 3

Explanation

Because the 802.1Q tunneling feature increases the frame size by 4 bytes when the metro tag is added, you must configure all switches in the service-provider network to be able to process maximum frames by increasing the switch system MTU size to at least 1504 bytes.

Question 4

Explanation

The VLAN ID field inside an 802.1q frame consists of 12 bits. Therefore we have 212 = 4096 VLAN IDs, theoretically.

802.1q_header.png

Question 5

Explanation

Each access port can be only assigned to one VLAN via the “switchport access vlan ” command.

Question 6

Explanation

This command is used to enable tagging of native VLAN frames on all 802.1Q trunk ports.

Answer A is not correct because even when the native VLAN is set to 1, all of the frames of the native VLAN are tagged.

Answer B is not correct because the control traffic still passes via the default VLAN (VLAN 1).

Answer C is not correct because all the frames are tagged with 4-byte dot1Q tag.

Answer D is not correct as “Control traffic continues to be accepted as untagged on the native VLAN on a trunked port, even when the vlan dot1q tag native command is enabled” according to this link: https://www.cisco.com/c/m/en_us/techdoc/dc/reference/cli/nxos/commands/l2/vlan-dot1q-tag-native.html

Question 7

Explanation

When you delete a VLAN, any LAN ports configured as access ports assigned to that VLAN become inactive. The ports remain associated with the VLAN (and inactive) until you assign them to a new VLAN.

Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/vlans.html

Question 8

Explanation

The PortFast feature is automatically enabled when voice VLAN is configured. When you disable voice VLAN, the PortFast feature is not automatically disabled.

Question 9

Question 10

Comments
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  1. Muhamad
    March 15th, 2019

    Pass on 13th march. My lab is HRSP and AAA dot1q. you should study them well.
    Few new questions, dump valid. Thanks certprepare!

    ====
    My email: muhamadawan1988(at)gmail(dot)com

  2. supportdonkey
    March 24th, 2019

    Muhamad is a fake! He just wants to sell dumps!

  3. elric
    March 30th, 2019

    Hi,
    Any body can help me the valid dump to dani_edi29 hotmail dot com as I will sit for exam this week.Thanks in advance!!

  4. NIC
    April 1st, 2019

    Did anybody get the answer for Q4? Isn´t it 32?

  5. NIC
    April 1st, 2019

    So, what is the answer for Q6?

  6. couldbe
    April 5th, 2019

    Use the vlan dot1q tag native global configuration command to configure the edge switch so that all packets going out an IEEE 802.1Q trunk, including the native VLAN, are tagged. Has to be used on IEEE 802.1Q Tunneling Port – QinQ.

  7. nahas
    April 29th, 2019

    Q7 states the after removing the vlan the interfaces go down until they are reassigned to a VLAN.
    I tried with GNS3 but I found that the port status remain up/up.
    After removing the vlan wih “no vlan x” command , I launched “show interfaces switchport” which displayed the vlan as inactive.
    “show vlan” dosen’t display anymore the vlan and the interface.
    “show ip interface brief” displays the port UP/UP.
    Does anyone know?

  8. mousti
    May 12th, 2019

    hi nahas
    this is true only in Nexus . in others platform the port in that vlan is inactive. show int X swichport>>>inactive

  9. darylchris
    May 20th, 2019

    Passed 300-115 yesterday, lab was AAA dot1q and HSRP sim and VTPv3 sim. I used IPHelper dump and its valid. My email : darylchris0511(at)gmail(dot)com

  10. Henry
    May 20th, 2019

    Q7 is weird
    The port WILL NOT go down, instead, it will just become “inactive”.
    “down” means no traffic at all. Well, I put a sniffer in the middle and I captured packets going back and forth.

  11. Henry
    June 2nd, 2019

    About Q6, choice is D is correct.
    Documents on internet don’t explain it properly. Here it is in plain English:
    When “vlan dot1q tag native” is setup on the local switch:
    – control traffic is SENT tagged (on vlan 1, you should already know this)
    – control traffic CAN BE RECEIVED tagged (the remote switch sends tagged control traffic on vlan 1) or untagged (the remote switch sends untagged control traffic on vlan 1)

  12. Super
    June 21st, 2019

    anyone have latest dumps? please send link

  13. MJxxx
    August 7th, 2019

    Q6 – D is correct.

    Very simple:
    Control traffic (=CDP, VTP, PAgP updates) is always sent via the native VLAN, which is by default VLAN 1.
    The native VLAN by default sends untagged traffic.

    You can change the native VLAN to be any other VLAN-X instead of VLAN 1, and remove VLAN1 from your trunk ports.
    You can also decide to tag the traffic on the native VLAN by setting the given command:
    “vlan dot1q tag native”

    -if you have done that, you have just tagged the control traffic which is sent over the native VLAN.

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