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.