<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2014) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2014) (Learn how and when to remove this template message) </Td> </Tr> <P> A virtual LAN (VLAN) is any broadcast domain that is partitioned and isolated in a computer network at the data link layer (OSI layer 2). LAN is the abbreviation for local area network and in this context virtual refers to a physical object recreated and altered by additional logic . VLANs work by applying tags to network packets and handling these tags in networking systems - creating the appearance and functionality of network traffic that is physically on a single network but acts as if it is split between separate networks . In this way, VLANs can keep network applications separate despite being connected to the same physical network, and without requiring multiple sets of cabling and networking devices to be deployed . </P> <P> VLANs allow network administrators to group hosts together even if the hosts are not directly connected to the same network switch . Because VLAN membership can be configured through software, this can greatly simplify network design and deployment . Without VLANs, grouping hosts according to their resource needs necessitates the labor of relocating nodes or rewiring data links . VLANs allow networks and devices that must be kept separate to share the same physical cabling without interacting improving simplicity, security, traffic management, or economy . For example, a VLAN could be used to separate traffic within a business due to users, and due to network administrators, or between types of traffic, so that users or low priority traffic cannot directly affect the rest of the network's functioning . Many Internet hosting services use VLANs to separate their customers' private zones from each other, allowing each customer's servers to be grouped together in a single network segment while being located anywhere in their datacenter . Some precautions are needed to prevent traffic "escaping" from a given VLAN, an exploit known as VLAN hopping . </P>

What layer of the osi model do vlans use