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VLAN Full Form

What Is The Full Form Of VLAN?

The full form of VLAN is Virtual Local Area Network.

VLAN is a custom network- composed of one or more LAN (local area networks). A network manager can use a VLAN for logically sub-dividing a LAN into different broadcast domains. It allows a group of devices in multiple networks to combine into one logical network. It results in a virtual LAN- administered like a physical LAN.

VLANs provide structure to the increasing number of networks in an area. It creates different small-sized sub-networks, making everything comparatively easy to handle. Without a VLAN, broadcast from a host reaches all network devices, which then process the received frames. It can result in an increased CPU overhead per device and overall reduced network security.

History of VLAN

  • Ethernet used to be a fast network in the 1980s with a speed of 10 Mbps. However, it was a broadcast network, and there were no commendable ways of connecting multiple Ethernet networks.
  • IP routing was a solution, but it was relatively slow and too expensive.
  • Walter David Sincoskie, an American computer engineer, looked for alternatives with less processing per packet.
  • He reinvented transparent bridging. But it made the centrally located switches bottlenecks- thus limiting scalability with more interconnected networks.
  • Sincoskie invented VLANs to help alleviate this problem. He introduced a multitree bridge. And while VLANs are common in modern Ethernet networks, they are no longer used similarly.
  • The Ethernet VLAN was described in 1998 in the first edition of the IEEE 802.1Q-1998 standard.
  • IEEE 802.1ad helped with the extension as it allowed nested VLAN tags in service of provider bridging.
  • The IEEE 802.1ah-2008 improved this mechanism.

Characteristics of VLAN

  • Every VLAN reduces the congestion by sharing the traffic between neighbouring VLANs- meaning, they act as separate LANs.
  • They can span up to multiple switches.
  • Relocation of terminals gets easier.
  • VLANs can simultaneously increase the number of domains for broadcast and decrease their size.
  • They reduce security risks because VLANs reduce the number of hosts receiving copies of the frames that the switches flood.
  • Separate hosts on a separate VLAN can hold sensitive data to improve security.
  • Network designs are flexible. You cannot only group people by physical locations, but also by departments.
  • One can achieve network changes easily by configuring a port apt for the VLAN.

Ranges of VLAN

  • VLAN 0-4095 – It is a reserved VLAN, and it cannot be seen or used.
  • VLAN 1 – It is a default VLAN of switches. One can’t edit or delete this VLAN but can use it.
  • VLAN 2-1001 – This one is a normal range of VLAN. You can edit, create, and delete it.
  • VLAN 1002-1005 – These VLAN ranges are CISCO defaults for FDDI and token rings, and you cannot delete them.
  • VLAN 1006-4094 – This VLAN is an extended range of VLANs.

Benefits of VLAN

  • It allows network administrators to add more security to the network communication.
  • VLAN provides flexibility since administrators can configure in a centralized environment even if the devices are in varied geographical locations.
  • They make relocation and expansion of a network device or network easier.
  • The bandwidth is used more efficiently with VLANs as compared to the LANs.
  • VLANs confine to their limited broadcast domains and thus reduce the traffic on any network significantly.
  • They decrease the traffic and latency on any network and the network devices- thus offering much better performance.
  • Each group has a different broadcast domain assigned to it- hence the security is extra to prevent other groups from viewing confidential information.
  • VLANs reduce the overall costs because they reduce the need for expensive routers to establish communication.

Limitations of VLAN

  • The risk of viruses is very high. One infected system can spread a virus through an entire logical network in no time.
  • VLANs make it very complex to manage larger and broader networks.
  • One needs more equipment and larger routers for controlling the workload in the large networks. It may lead to equipment limitations.
  • VLANs are more effective at controlling latency as compared to a WAN. But they are less efficient than LAN.
  • One needs to configure all the switches for accommodation when adding a new VLAN.
  • The interoperability can be quite complex with a VLAN.

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