Virtual+LANs+(KC)

= Virtual LANs =

Definition
VLAN or Virtual LAN is a subnet that is created via the configuration of multiple network switches.

What's the Purpose?
Virtual LANs tend to solve the problem of containing traffic that are within gathered groups which are placed in different geographic locations. The VLAN allow moves, adds, and changes which are preformed by the software at a machine instead of configuring it manually and changing out different cables.

How It Works
There are two different ways to VLAN. The first starts with configuring the VLAN on the physical network. This needs to be done at the port level where the network switch is located. During this event, the user will assign the VLAN to the port that the switch is on and any traffic that goes into or out of this port becomes tagged with the VLAN identification number. This helps the device that is connected to the port from changing the VLAN ID value. This also means that if the device moves around to different ports, that the new port must be configured properly for the correct VLAN. This can prevent different devices that are connected to the port to become members of different VLANs.

The second way starts with assigning the VLAN ID before any transmission of packets begin. The end device has the ability to be easily moved from one VLAN to another without any changes to the physical port switch. The only requirement of this is that the device must have complete knowledge of IEEE 802.1Q VLAN tagging. The device must know how to tag, transmit a tagged packet, as well as how to physically open a packet that has been tagged previously.

Facts:

 * The Virtual LAN could be connected to a larger LAN or WAN and can also span into different cities. The VLAN may be grouped into several different physical subnets by figuring out where the devices are along the cable or on the same network hub.
 * The VLAN is created by a software program and not manually moving cables.
 * VLAN can cut costs for networks because it allows users to move and change locations in a network without changing network addresses.

What is Needed?

 * Hyper-V servers are necessary for network adapters with IEEE 802.1Q support.
 * Network switches need IEE 802.1Q support.
 * The routers also need IEEE 802.1Q support so that the tagged packets can be properly routed.

Overall
Virtual LANs can help to contain a threat so they are safe to use. VLANs also have added security benefits and can also increase bandwidth as well as data flow throughout specific devices. VLANs can be built at any size so therefor they can be on any type of network. The smaller the network, the better security benefits it can have. However, the bigger the network, the less effective the security may be. Smaller VLANs only allow for a few fevices that can communicate with each other and it restricts data exchanges that are necessary.

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http://www.certiguide.com/netplus/cg_np_IVVLANsCreatingVirtualLANs.htm http://happyrouter.com/free-video-how-to-configure-vlan-in-the-cisco-ios http://www.24x7mag.com/issues/articles/2007-12_07.asp http://www.virtualizationadmin.com/articles-tutorials/microsoft-hyper-v-articles/networking/introduction-vlan.html http://encyclopedia2.thefreedictionary.com/virtual+LAN