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VLAN Questions

March 23rd, 2017 in ICND2 200-105 Go to comments

Question 1


On an Ethernet connection, a duplex mismatch is a condition where two connected devices operate in different duplex modes, that is, one operates in half duplex while the other one operates in full duplex. Duplex mismatch can easily cause collision domain issue as the device that operates in full duplex mode turns off CSMA/CD. So it is eager to send data immediately without checking if the link is free to use -> A is correct.

An “inband path” is the path which provides path for management traffic (like CDP, VTP, PAgP…) but we are not sure why congestion on the switch inband path can cause collision domain issues. Maybe congestion on inband path prevents the JAM signal (sent when a collision occurs on the link) to be sent correctly on the link.

Question 2


By default, all ports on a new switch belong to VLAN 1 (default & native VLAN). There are also some well-known VLANs (for example: VLAN 1002 for fddi-default; VLAN 1003 for token-ring…) configured by default -> A is not correct.

To communicate between two different VLANs we need to use a Layer 3 device like router or Layer 3 switch -> B is correct.

VLANs don’t affect the number of collision domains, they are the same -> C is not correct. Typically, VLANs increase the number of broadcast domains.
We must use a different network (or sub-network) for each VLAN. For example we can use for VLAN 1, for VLAN 2 -> D is correct.

A switch maintains a separate bridging table for each VLAN so that it can send frame to ports on the same VLAN only. For example, if a PC in VLAN 2 sends a frame then the switch look-ups its bridging table and only sends frame out of its ports which belong to VLAN 2 (it also sends this frame on trunk ports) -> E is correct.

We can use multiple switches to expand VLAN -> F is not correct.

Question 3


If we configure an access port as follows:

Switch(config)#interface fa0/1
Switch(config-if)#switchport mode access

Then this interface, by default, will belong to VLAN 1. Of course we can assign another VLAN to this port via the “switchport access vlan {vlan-number}” command.

Question 4

Question 5


The “switchport access vlan 1” assigns VLAN 1 to this interface. In fact, by default all access ports belong to VLAN 1 so this command is hidden in the switch configuration.

Question 6


A VLAN does not need to be assigned to any port -> B is not correct.

An access port can only receive traffic from one VLAN -> C is not correct.

If not assigned to a specific VLAN, an access port carries traffic for VLAN 1 by default -> D is not correct.

An access port will drop packets with 802.1Q tags -> A is correct. Notice that 802.1Q tags are used to packets moving on trunk links.

Question 7

Comments (4) Comments
  1. ash
    March 30th, 2017

    where are the questions ???????????????

  2. rfvaz
    April 1st, 2017

    Where are the questions? Need I to be a premium member?

  3. Tubik
    April 11th, 2017

    Yes you have to pay for a premium to see questions