Vlan switching technology Vlan is built on a LAN switch and implements division and Management of logical working groups in a software manner. Its Switching technology generally includes port switching, three types of frames exchange and Token exchange. 1. the port switch is also called the configuration switch. The initial method is to manually configure the port to one or more shared hubs connected through the backplane, A number of independent shared media segments composed of ports can be formed. Each user connected to a port is allocated to one of these segments. in recent years, it has developed into a device called a port switch, which is controlled and managed by hardware and software on one or several port switches connected through backboards, divides the port on the switch into several shared independent VLANs. the port switching mode is characterized by the flexibility of port user groups to form small-scale VLANs. in a global switch network, port switching can provide effective and flexible frontend port combinations for global VLANs. the vlan, the port user, and the bandwidth of the entire vlan are restricted. 2. frame switch is a vlan switching method based on Switched Ethernet. after a common L2 Switch receives a data frame from a port, it analyzes the mac address contained in the data frame and forwards the data frame to the corresponding port using the port/mac address ing table in the switch. when processing a broadcast frame, the broadcast frame is sent to all ports except the inbound port. vlan switches can isolate information transmission between VLANs. Therefore, traffic between ports on different VLANs is blocked. if a port receives a broadcast domain, the frame can only be forwarded to other ports of the vlan to which the port belongs. the most important feature of this switch mode is that it improves the efficiency of switch bandwidth utilization, and provides more flexible management than port switching, and supports dynamic vlan division. 3. the cell switch technology refers to the use of atm technology for data exchange, similar to frame exchange, composed of one or more interconnected atm switches to form a core network system, exchange in the form of credit. atm is a public basic technology for LAN and WAN. It combines two data exchange modes: line exchange and storage forwarding. It uses underlying exchange and optical fiber transmission technologies, with network bandwidth ranging from a few megabytes to hundreds of megabytes or even Gbit/s, it can fully meet the needs of data, voice and video transmission, and it is very easy to set up man for various applications, qos is also ensured. atm also allows end-point customer sites to be added to multiple VLANs, allowing one physical cable to implement multiple logical connections. atm implements Common atm lan simulation technologies for VLANs.