18 Questions
What is a primary benefit of dividing a LAN into multiple VLANs?
Improved IT efficiency
What is the primary purpose of the Native VLAN?
Used for trunk links only
What is the default VLAN in a Cisco switch?
VLAN 1
What is the result of reducing the number of broadcast domains in a LAN?
Improved network performance
What is the benefit of using VLANs in terms of network security?
Only devices in the same VLAN can communicate with each other
What is the purpose of a Management VLAN?
Carrying SSH/Telnet VTY traffic
Which VLAN range is typically used by Service Providers?
1006 - 4095
What is the purpose of the vlan.dat file in flash?
Stores VLAN details
What is the default name given by Cisco IOS if a VLAN is not named?
vlan-
What configuration mode is required to create a VLAN?
Global configuration mode
Which VLANs are auto-created and cannot be deleted?
1002-1005
What is required to synchronize VLANs between switches?
VTP configurations
What is the consequence of deleting a VLAN without reassigning its member ports?
The VLAN is deleted, but the member ports still transmit traffic
What is the purpose of the switchport mode trunk command?
To configure the port for permanent trunking mode
What is the effect of deleting the vlan.dat file on a switch?
The switch reverts to its default VLAN configuration
What is the purpose of specifying the native VLAN on a trunk link?
To specify the VLAN that untagged traffic should be assigned to
What is the command to verify the default VLAN configuration on a switch?
show vlan brief
What is the consequence of not reloading the switch after deleting all VLANs?
The changes do not take effect until the switch is reloaded
Study Notes
Benefits of VLANs
- Smaller broadcast domains reduce network traffic and improve performance
- Improved security as only users in the same VLAN can communicate with each other
- Improved IT efficiency by grouping devices with similar requirements
- Reduced cost as one switch can support multiple groups or VLANs
- Simpler management as similar groups require similar applications and network resources
Types of VLANs
- Default VLAN (VLAN 1) is the native and management VLAN and cannot be deleted or renamed
- Data VLAN is dedicated to user-generated traffic (email and web traffic)
- Native VLAN is used for trunk links only
- Management VLAN is used for SSH/Telnet VTY traffic and should not be carried with end-user traffic
- Normal Range VLANs are 1-1005, Extended Range VLANs are 1006-4095
- VLANs 1002-1005 are reserved for legacy VLANs and are auto-created and cannot be deleted
VLAN Configuration
- VLAN details are stored in the vlan.dat file
- VLANs are created in global configuration mode using the 'vlan' command
- A unique name must be specified to identify the VLAN
- The IOS command to create a VLAN is
Switch(config)# vlan vlan-idandSwitch(config-vlan)# name vlan-name
Deleting VLANs
- VLANs are deleted with the
no vlan vlan-idcommand - Caution: reassign all member ports to a different VLAN before deleting a VLAN
- All VLANs can be deleted with the
delete flash:vlan.datordelete vlan.datcommands - Reload the switch after deleting all VLANs
VLAN Trunks
- Trunks are layer 2 and carry traffic for all VLANs
- Trunk configuration commands include
switchport mode trunkand setting the native VLAN and allowed VLANs on the trunk link
Test your knowledge on VLAN configuration, creation, and management in small to medium-sized businesses and service providers. Learn about the different VLAN ranges, reserved VLANs, and VTP configurations. This quiz covers the basics of VLAN configuration and its applications.
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