Chapitre 6

Question 1

C’est quoi le but du VLAN

Answer 1

Organisation et flexibilité

Question 2

Le VLAN est considéré comme étant un réseau logiquement…

Answer 2

Séparé

Question 3

Quelles sont les seules requêtes qui sont quand même envoyées sur les VLANs?

Answer 3

Les diffusions et les requêtes ARP.

Question 4

Quels sont les bénéfices des VLANS?

Answer 4

• Sécurité
• réduction des cout
• Meilleur performance
• • petits domaine de diffusion
• maintenance plus facile

Question 5

Ou est-ce-que l’on peut utiliser le mode trunking?

Answer 5

entre 2 switchs

entre une switch et un serveur 802.1qNIC*

Question 6

pour déplacer un pont d’un VLAN à un autre il faut utiliser :

Answer 6

switch port access VLAN #

Question 7

Qu’est ce qui arrive lorsqu’on utilise no switch port access vlan #?

Answer 7

retourne le VLAN au VLAN 1

Question 8

lorsqu’on utilise no vlan vlan-id?

Answer 8

efface un vlan spécifique et si un port spécifique est associé à ce vlan celui-ci devient inactif.

Question 9

Avec quoi est-ce-qu’un VLAN native est-t’il associé?

Answer 9

un port trunk 802.1q

Question 10

Qu’est-ce-qu’un port trunk?

Answer 10

C’est un port faisant le lien entre deux commutateurs ayant plus de 1 VLAN.

Question 11

Traffic coming from many diffrent VLANs have to be what?

Answer 11

Tagged.

Question 12

Quelle est la taille d’une étiquette VLAN

Answer 12

4 octets

Question 13

Les trames n’ayant pas d’étiquette sont envoyé à quel VLAN ?

Answer 13

Au VLAN par défaut, 1.

Question 14

Les VLAN native sont défini avec quel spécification?

Answer 14

IEEE 802.1Q

Question 15

Qu’est-ce-qu’un VLAN voice, VoIP a besoin pour bien fonctionner?

Answer 15

• une bandepassante qui assure une QoS
• Transmission priority
• Rerouting capabilities
• Latency of maximum 150ms

Question 16

C’est quoi un trunk?

Answer 16

C’est un lien point à point entre deux commutateurs qui detiennent chacun au moins deux vlans.

Question 17

what does the vlan tag field consist of?

Answer 17

• Type field
• user priority
• Canonical format identifier
• VLAN ID

Question 18

What happens when a Cisco switch receives an untagged frame?

Answer 18

It sends it to the native VLAN.

Question 19

What happens when a cisco switch receives an untagged frame and there is no native VLAN as well as no trunk port?

Answer 19

The frame is dropped.

Question 20

What does CoS stand for?

Answer 20

Class of service.

Question 21

What does the command do : show interfaces fa0/18 switchport?

Answer 21

displays the configuration of the interface switch port

Question 22

Where are the Vlan database configuration stored?

Answer 22

In a data file called vlan.dat

Question 23

What does the switchport mode access command do?

Answer 23

It configures a PORT assigned to a VLAN as a Permanently access mode port.

Question 24

What does the command switchport access vlan vlan-id do?

Answer 24

it assigns the chosen port to a chosen vlan.

Question 25

What command should one use to configure many ports to a specific vlan?

Answer 25

interface range f0/X - Y

Question 26

What is a special property of the switchport access vlan command?

Answer 26

it forces the creation of a VLAN if it wasn't create prior to it's usage.

Question 27

What command should you use to display a list of vlans on screen

Answer 27

show vlan brief

Question 28

What command do you use to put a port back into the default vlan 1?

Answer 28

no switchport access vlan

Question 29

How do you delete a vlan?

Answer 29

conf t -> no vlan vlan-id -> end

Question 30

Before deleting a Vlan what is preferable to do?

Answer 30

reassign all the ports associated to that vlan to another vlan or to the default vlan otherwise those ports will not be able to communicate.

Question 31

To allow a vlans on a specific trunk link what command should you use?

Answer 31

swichport trunk allowed vlan X, Y, Z, ...

Question 32

What does the command "no switchport trunk allowed vlan" do?

Answer 32

It reset the trunk port configuration to allow all vlans to pass through it.

Question 33

What happens if you use the command "no switchport trunk native vlan"

Answer 33

it reset the native vlan to its default value which is vlan 1.

Question 34

To reset a port to access mode what command should one use on that port?

Answer 34

switchport mode access

Question 35

To see the switchport configurations on a specific port what command should one use?

Answer 35

show interfaces f0/1 switchport

Question 36

What is inter-vlan routing?

Answer 36

The process which is used to forward network traffic from one vlan to another using routing.

Question 37

Quels sont les trois types d'inter-vlan routing?

Answer 37

- Legacy inter-vlan routing - Router-on-a-stick - Layers 3 switching using SVI's

Question 38

What is legacy inter-vlan routing?

Answer 38

There is an interface for each vlan on the router.

Question 39

What is Router-on-a-stick routing?

Answer 39

The router transmits and differentiates between two vlans thanks to subinterfaces that are matched to their vlan counterparts. - One port, many vlans communicating through it.

Question 40

What is the encapsulation dot1q used for?

Answer 40

It is used to encapsulate a frame with the right vlan tag when in the router. In example: interface g0/0.10