Network infrastructure vlan (virtual local area network)

VLAN (Virtual Local Area Network) in Chinese named "virtual LAN."
Virtual LAN (VLAN) is a set of logical devices and users, and users of these devices is not limited to physical location, the function may be based on factors, sectors and applications organize them together, communication between each other if they are the same segment as the eponymous virtual local area network. VLAN is a relatively new technology, working at Layer 2 and Layer 3 of the OSI reference model, a VLAN is a broadcast domain, the communication between the router VLAN through the third layer to complete. Compared with traditional LAN technology, VLAN technology is more flexible, it has the following advantages: mobile network equipment, additions and modifications to reduce administrative overhead; can control broadcasting activities; to improve network security.
In a computer network, a Layer 2 network may be divided into a plurality of different broadcast domains, a broadcast domain corresponding to a specific user group, these different default broadcast domains are isolated. You want to communicate, via one or more routers require different broadcast domains. This is called a broadcast domain VLAN.
vlan division manner divided into physical and logical segmentation. Dividing a physical broadcast domain is divided using a router, a relatively high cost. And logical partitions using a switch them into a small broadcast domain.
vlan advantage controlled broadcasting, enhancing network security, simplify network management, and so on.
vlan vlan divided into static with dynamic vlan. Static Port-based vlan is vlan static, the same port can host interoperability, a host of different ports can not be interoperability. Dynamic vlan is to be divided based on MAC addresses.
vlan ID of the range. 0 4095 system with limited use, the user can not view and use the vlan. 1 is the Cisco default vlan user can use it, but you can not delete it. 2-1001 is vlan for Ethernet, users can create, use, and delete these vlan. Cisco 1002-1005ID for Token Ring and FDDI default vlan users can not delete these vlan. 1006-1024 is the system users only use, the user can not view and use the vlan. The 1025-4096ID is used only for Ethernet vlan.