Design and Implementation of Wireless Access Network IP Domain Domain Network The development of the wireless access network in China is still very rapid. Many people may not understand the design and implementation of the network layer of the wireless IP metropolitan area network in the wireless access network. It does not matter. After reading this article, you must have a lot of gains. Hope This article can teach you more. With the development of wireless access network technology and integrated circuit technology, wireless access network communication has been widely used. Mobile operators, mainly telephony services, provide support for wireless access network data services, but as public telecommunications serving the public, data transmission capabilities are shared among multiple users. For some special departments: such as public security and fire protection It is difficult to ensure effective bandwidth support when needed, not to mention that there are often sensitive information that is not suitable for transmission in public telecommunications networks. These determine that the public wireless data service is difficult to be effectively applied in these professional departments. On the other hand, with the implementation of the Sanjin project, these departments gradually established a more complete wired network throughout the city. For example, the optical fiber of the public security system was laid in the grassroots police station. Therefore, selecting the appropriate grassroots unit, using a wired network, and setting up a radio access network communication base station covering a certain range can achieve network-wide coverage of the network, thereby realizing a wireless IP metropolitan area network. Design BS is a wireless base station, which is connected to a wired network, and MS is a mobile terminal. SCC is the system control center, which contains BS, user and terminal databases, and the operator can input and modify data through the CMT management platform. In SCC, each user contains static parameters such as account number, password, and business authority. When a user logs in, SCC assigns an IP address to the terminal and records dynamic parameters such as the BS address that the user accesses. SCC also needs to authenticate and manage each BS and terminal equipment to avoid missing devices from accessing the system and compromising system security. SPC is a business processing center and is a business processing unit in the system. It supports any type of IP business. To disperse business processing load, several SPCs are allowed in the system. Each SPC operates independently to complete one or several destination IP segments. Business processing functions. Each SPC has at least two network interfaces, one is assigned an IP address for communication with SCC and BS, and the other interface serves as the gateway interface of the wireless access network network. According to the wired network routing protocol, the SPC handles IP services The segment will be routed to the corresponding interface according to the destination IP address, so that it can be intercepted by the SPC and complete the service forwarding function. For example, in Figure 2, an SPC has three network interfaces, 10.3.23.50 as the SPC's own IP address for TCP-based communication with SCC and BS, and 10.72.0.0/20 and 10.72.224.0/19 as gateways For the interface, packets with 10.72.0.0/20 and 10.72.224.0/19 as the destination address segment will be routed to the corresponding SPC interface. After the system is started, the BS and SPC establish connection with the SCC respectively to complete the initialization process of each BS and SPC, and then the SCC delivers the SPC list to each BS, informing each BS of the address of each SPC and the scope of IP services handled by each BS Then establish an IP tunnel with each SPC. After each terminal is turned on, it first scans the wireless channel, finds the BS with the best signal as the access node, and initiates a network access request to the BS. The request contains the device serial number, user identification, user key and other information. The BS will correspond The information is forwarded to the SCC. After the SCC authentication is passed, the user's access base station is registered, the user status is modified, the user is assigned an IP address according to the user attribute, and the corresponding BS and terminal are notified to complete the user's network access process. Then the SCC determines the SPC that handles the terminal service based on the IP address just assigned, and notifies the SPC terminal access location (that is, the address of the BS). Every time the terminal status changes in the future, the SCC will push the status to the corresponding SPC in time, so that the user status saved in the SPC is up to date. The IP packet entering the wireless network may be generated by the terminal of the wireless access network or generated by a node outside the wireless access network. The IP packet generated by the wireless access network terminal is first received by the corresponding base station. The base station selects the SPC that processes the user's service, and forwards the complete IP message to the SPC through the tunnel between the base station and the SPC. The SPC will extract it from the TCP message. For the original message to the terminal, if the destination address is within its own processing range, the base station where the corresponding destination address is located is searched, and the original message is forwarded to the destination base station by tunnel again, and the destination base station sends it to the destination terminal through the wireless interface Processing; otherwise, the SPC adds the Layer 2 frame header to the original packet and forwards it to the corresponding router, so that the packet enters the internal network, and is sent to the destination terminal or routed to the gateway interface of other SPCs through the normal routing process for processing. According to the design process, the packets entering the network outside the wireless network will be routed according to the destination address, and will inevitably be routed to the gateway interface of an SPC. In summary, when the SPC receives an IP message, it will process the message according to Figure 3. When the terminal moves, it needs to update the location. To this end, when the terminal continuously detects network signals and finds a cell with a better signal, the terminal initiates a handover request to the BS of the new cell. The BS responds and forwards the handover request to the SCC. The SCC updates the user status and notifies the SPC user of the new location The SCC sends a handover notification to the original access cell and sends a confirmation message to the new cell. Perkins 76-200KW Diesel Generator Perkins 76-200Kw Diesel Generator,Perkins Silent Type Diesel Generator,Perkins Container Type Diesel Generator,Perkins Super Silent Diesel Generator Shanghai Kosta Electric Co., Ltd. , https://www.shkostagenerator.com