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CCNA Basics: What is VLAN ?

August 08, 2019 , , ,

What is VLAN ? 

A VLAN, or Virtual Local Area Network, is a logical grouping of network devices that are part of the same LAN but might be physically situated on various network segments. It enables network managers to divide a physical network into more manageable, independent networks. Network administration is made simpler, traffic management is improved, and network security is increased by this segmentation. 

What is the benefits of using VLAN ?

Logical Segmentation: VLANs create logical groups of devices, allowing them to communicate with each other as if they were on the same physical network, even if they are physically connected to different parts of the network. 

Security: By isolating devices into different VLANs, you can control communication between them, restricting access to sensitive data and preventing unauthorized access to specific parts of the network. 

Traffic Management: VLANs help optimize network traffic by reducing broadcast domains, which can improve network performance and reduce congestion.

Simplified Administration: VLANs can be configured based on logical groupings (e.g., departments, projects) rather than physical locations, making it easier to manage and maintain the network. 

How to configure VLAN ? 

Below is the example on the switch to configure the VLAN (IT Dept and Sales) as VLAN 2 and VLAN 3 accordingly. 

CCNA Basics: What is VLAN ?

Configuration Example 

NDNA_S1>enable
NDNA_S1#Config t
NDNA_S1(config) # vlan 2
NDNA_S1(config- vlan) # name IT Dept
NDNA_S1(config- vlan) #exit
NDNA_S1(config)# interface range Gi0/0-10
NDNA_S1(config-if-range)# switchport mode access
NDNA_S1(config-if-range)#switchport access vlan 2
NDNA_S1(config-if-range)# exit
NDNA_S1(config) # vlan 3
NDNA_S1(config- vlan) # name Sales
NDNA_S1(config- vlan) #exit
NDNA_S1(config)# interface range Gi0/17-24
NDNA_S1(config-if-range)# switchport mode access
NDNA_S1(config-if-range)#switchport access vlan 3
NDNA_S1(config-if-range)# exit
NDNA_S1#

Hope the example helps to understand the concept of the VLAN in a LAN environment.