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VLAN Questions

April 9th, 2017 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.

Only answer D is best choice because control traffic (like CDP, VTP, STP, DTP…) uses VLAN 1 for communication. When the native VLAN is tagged (VLAN 1 by default) all control traffic is tagged too. If the native VLAN is not VLAN 1 then all the control traffic on VLAN 1 is still tagged by default (without using above command).

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.

Comments
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  1. Anonymous
    April 26th, 2017

    Passed today,
    191q dump is all you need.
    I found the vce that still works with A+ Player here https://www.itlibraries.com/downloads/300-115/

    Good luck all!

  2. switchelp
    April 30th, 2017

    @ALL Attention 191q is not sufficient …

  3. Niazi
    May 9th, 2017

    I failed with 191 q dumps in Feb-2017
    how it is valid in end of April
    Ha Ha Ha……

  4. CiscoGuy
    May 12th, 2017

    Niazi, because they switch the questions around but still from the same sources including 191Q

  5. Mat
    May 16th, 2017

    I passed today with the dumps from the link above but it has 251 questions.
    On my second try I have to admit went the first time with the question from here but they only covered 50% of what was on the exam.

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