VLAN tutorial

This vlan tutorial answers the common questions with answers asked on VLAN technology.


What is a VLAN

VLAN, which stands for virtual LAN is a networking concept which is used for segregating LAN networks. It is used for creating multiple LAN networks on a single switch.

Is VLAN a device or a technology

VLAN is not a device. It is a technology which is implemented on switches. Switches can be configured with respective vlans to segregate the LAN networks.

What happens after vlans are configured on switches.

Take an example where a 24 port switch is configured with 3 VLAN. After the VLAN’s are created, the ports required are assigned to the respective vlan. After the ports are associated, the ports which are associated with the same vlan become part of 1 broadcast domain. Before the configuration of VLANs, all ports on the switch was part of one broadcast domain, which is now segregated into 3 domains after 3 vlans are configured.

What is the benefit of vlan

As explained above, vlans would segregate the broadcast domain into multiple domains. This would ensure that broadcast traffic from one VLAN would not reach other network, which would significantly improve the performance of the networks.

Can a switch achieve communication between two vlans

In order to communicate between two vlans, a router or a layer 3 switch is required. A layer 2 switch does not have the capacity for allowing communication between vlans.

What is vlan tagging

VLAN tagging is a technology which is used where the generic Ethernet frame is identified with the use of VLAN headers. 802.1Q is the IEEE standard for tagged frames and Cisco ISL is a Cisco proprietary protocol used for VLAN tagging

Do routers support VLAN

Routers also support VLAN. A routers interface can be virtually divided into multiple sub interfaces and each interface mapped with unique VLAN ID and sub interfaces

Is it possible to have VLAN on a wireless network

Advanced access points can be configured with VLAN for each wireless networks.

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