Virtual LAN Network(VLAN)

  • VLAN is a concept where a larger network(LAN) is broken into number of smaller virtual network known as virtual LAN network.
  • VLAN breaks the broadcast domain that is LAN with larger broadcast domain is broken into multiple smaller broadcast domain.

VLAN Membership: This defines what characteristics can be used to to classify multiple stations into multiple VLAN.

This can be on the basis of:

  • Port Number :

The switch port number can be used a membership characteristics. Example: Port 1, 2,3 can be grouped to VLAN 10, port: 4, 5, 6 can be grouped to VLAN 5.

  • MAC Address:

Even the MAC address can be used as a membership characteristics. For example, stations with MAC E21342A12334 and E21342A12335 belong to VLAN 5.

  • IP Address:

Some VLAN vendors use the 32-bit IP address as a membership characteristic. For example, the administrator can stipulate that stations having IP addresses,,, and belong to VLAN 5.

  • Multicast Address:

Some VLAN vendors used the multicast IP address as a member characteristics.

  • Combination:

Even the multiple above characterstics from above can be used as a membership characteristics.

Advantages of VLAN:

Security: One of the biggest advantage of VLAN is its security. Since packet from one VLAN can not be send or received from/to other VLAN. Stations belonging one VLAN can send the broadcast message with guaranteed assurance that these packets will not reach to other groups.

Creating Virtual Work Groups:

VLAN can be used to create virtual work group. Each group can work independently and they do not need to process the unnecessary packet from other groups. This can reduce the congestion in the network leading to better and efficient use of bandwidth.

Categories: Networking

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