What is  VLAN      

VLAN stands Virtual Local Area Network and it is a defined in the IEEE802.1q standard.  In the VLAN the computers behaves as they are connected to the same LAN even though they may actually be physically located to the other segments of the network.  It is a broadcast domain that is created by the switched in the network.  In the VLAN if a computer is physically moved to another location, it can stay on the same VLAN without changing the computer hardware.  

VLAN removes the limitations of using the physical architecture by creating the logical segmentations and grouping together the computers by using their MAC addresses, protocols, and the port numbers.  VLANs are created by the software, which provides the flexibility to create them. 

In the VLAN, only the VLAN enabled devices can send/receive data packets. They are created to provide the segmentation services and the services like scalability, security and the management of the computer network.  VLAN controls the traffic in the network.   There are following three types of the VLAN.

Level 1:  It is also known as port based VLAN, which defines the virtual network.

Level 2:  It is also known as MAC-Address based VLAN, which defines the VLAN according to the MAC address of the machine.

Level 3:  Level 3 VLAN consists of the Network Address Based VLAN and the Protocol Based VLAN.

VLAN offers the many advantages and some of them are described below.

Advantages

• It provides the flexibility to the administration of the network.
• It reduces the broadcast traffic.
• It increases the security because the information is encapsulated.
• It provides the increased performance of the network.
• It provides the physical topology independence.
• VLAN offers the increased bandwidth to the network users.
• VLAN provides the easy management of a specific project or a specialized application.
• Creating VLAN with the network switches is cheaper than creating the routed network by using the routers.
• Plug and play configurations without requiring additional hardware.
• Dynamic reporting across the network.

VLAN also has some limitations that have been described below.

• VLAN provides the little security so an intruder with little knowledge of routing and encryption can access it.
• It provides the broadcast limitations, device limitations the ports constraints.
• MAC based VLAN require the managerial overhead to manage the network.

VLAN is required if you have:

• More than 200 devices on your local area network.
• Group of the users require more security.
• Groups of the users are being slowed down by the broadcasts.
• If you have more broadcast traffic on your LAN.