Virtual Local Area Network -VLAN

A virtual local area network VLAN is a logical group of workstations, servers and network devices that appear to be on the same LAN despite their geographical distribution. A VLAN allows a network of computers and users to communicate in a simulated environment as if they exist in a single LAN and are sharing a single broadcast and multicast domain. VLANs are implemented to achieve scalability, security and ease of network management and can quickly adapt to changes in network requirements and relocation of workstations and server nodes.

Higher-end switches allow the functionality and implementation of VLANs. The purpose of implementing a VLAN is to improve the performance of a network or apply appropriate security features.

Computer networks can be segmented into local area networks (LANs) and wide area networks (WANs). Network devices such as switches, hubs, bridges, workstations and servers connected to each other in the same network at a specific location are generally known as LANs. A LAN is also considered a broadcast domain.

A VLAN allows several networks to work virtually as one LAN. One of the most beneficial elements of a VLAN is that it removes latency in the network, which saves network resources and increases network efficiency. In addition, VLANs are created to provide segmentation and assist in issues like security, network management and scalability. Traffic patterns can also easily be controlled by using VLANs.

The key benefits of implementing VLANs this include:

1. Allowing network administrators to apply additional security to network communication
2. Making expansion and relocation of a network or a network device easier
3. Providing flexibility because administrators are able to configure in a centralized environment while the devices might be located in different geographical locations
4. Decreasing the latency and traffic load on the network and the network devices, offering increased performance

VLANs also have some disadvantages and limitations as listed below:

1. High risk of virus issues because one infected system may spread a virus through the whole logical network
2. Equipment limitations in very large networks because additional routers might be needed to control the workload
3. More effective at controlling latency than a WAN, but less efficient than a LAN 

prepared by IBRAHIM MCHUCHURI