ch. 8 Implementing Ethernet Virtual LANs

Question 1

What is 802.1Q

Answer 1

IEEE trunking protocol

Question 2

how does 802.1Q work?

Answer 2

tags each frame with the VLAN ID and can support up to 4094 realistically

Question 3

What is the normal range of VLAN IDs

Answer 3

1 - 1005

Question 4

What is the extended range of VLAN IDs

Answer 4

1006 - 4094

Question 5

What is the special VLAN ID on each trunk and how does it work

Answer 5

the native VLAN (VLAN 1) 802.1Q doesn’t add a header to this frame and the receiving switch takes that frame as a message to the VLAN 1

Question 6

What is the purpose of the native VLAN

Answer 6

To support connections to devices that do not understand trunking

Question 7

What do you need in order to send packets between VLANs

Answer 7

Router or a Layer 3 switch - multilayer switch

Question 8

What are the steps to configure VLAN

Answer 8

Configure a new vlan and then assign interfaces

Question 9

How do you configure a vlan

Answer 9

use the vlan-id command in global config mode to create the VLAN and to move the user into VLAN config mode
[optional] Use the name command in VLAN config mode to list a name for the vlan

Question 10

How do you assign an access interface

Answer 10

use the interface command in global config mode to move into interface config mode for each desired interface
use the switchport access vlan command in interface config mode to specify the vlan number
[optional] use the switchport mode access command in inheritance config mode to make this port always operate in access mode

Question 11

What is VTP and how does it work

Answer 11

VLAN Trunking Protocol - advertises each VLAN configured in one switch(with the vlan number command) so that all other switches in the campus learn about that VLAN

Question 12

How do you disable VTP

Answer 12

use the command vtp mode transparent or vtp mode off

Question 13

How do you create a Trunk between two vlans

Answer 13

use the switchport mode trunk on both sides of an interface between two switches in interface mode

Question 14

What is DTP and what does it do

Answer 14

Dynamic Trunking Protocol - used to negotiate forming a trunk between two cisco devices

Question 15

What command allows you to define the admin trunking mode

Answer 15

switchport mode

Question 16

what does the switchport command access do

Answer 16

Always act as an (nontrunk) port

Question 17

What does the switchport command trunk do

Answer 17

Awlays act as a trunk port

Question 18

What does the switchport command dynamic desirable do

Answer 18

Initiates negotiation messages and responds to negotiation messages to dynamically choose whether to start using trunking

Question 19

What does the switchport mode command dynamic auto do

Answer 19

Passively waits to recieve trunk negotiation messages at which point in the switch will respond and negotiate whether to use trunking

Question 20

How to configure a voice vlan

Answer 20

vlan vlan-id - global conifg mode
interface type number -global conifg mode
switchport access vlan id-number - interface mode
switchport mode access - interface mode
switchport voice vlan - interface mode

Question 21

What are the commands to check the status of trunking-related facts

Answer 21

show interfaces trunk and show interfaces switchport

Question 22

what is vlan hopping

Answer 22

when frames from one vlan are sent over to another vlan when there is a native vlan mismatch