Design and Implementation of IP Domain Network for Wireless Access Networks

China's wireless access networks are still developing very rapidly. Many people may not understand the network layer Design and Implementation of Wireless ip man in Wireless Access networks. After reading this article, you will surely have a lot of GAINS, I hope this article will teach you more things. With the development of wireless access network technology and integrated circuit technology, wireless access network communication has been widely used. Mobile operators that focus on telephone services provide support for wireless access network data services. However, as public telecommunications that serve the masses, data transmission capabilities are shared among multiple users, for some special departments, such as public security and fire protection, it is difficult to guarantee effective bandwidth support when needed. Moreover, there are often some sensitive information that is not suitable for transmission in public telecom networks. This makes it difficult for public wireless data services to be effectively applied in these professional departments.

On the other hand, with the implementation of the Sanjin project, these departments have gradually established well-established wired networks throughout the city. For example, the optical fiber cables of the Public Security System have been laid to grass-roots police stations. Therefore, selecting appropriate grass-roots units and setting up wireless access network communication base stations that cover a certain range can achieve full network coverage and achieve wireless ip man.

Solution Design

System Composition 1 is shown in. In the figure, BS is a wireless base station connected to a wired network, and MS is a mobile terminal. SCC is a system control center that includes BS, users, and end databases. operators can input and modify data through the CMT management platform. In SCC, each user contains static parameters such as account and password, and business permissions. When a user logs on, SCC assigns an IP address to the terminal and records dynamic parameters such as the BS address accessed by the user. SCC should also authenticate and manage each BS and terminal device to prevent loss of device access to the system and damage system security.

SPC is a service processing unit in the system. It supports any type of IP services. To distribute the service processing load, several SPC instances are allowed in the system, and each SPC operates independently, the service processing function of one or more destination IP segments is completed. Each SPC has at least two network interfaces. One is assigned an IP address for communication with SCC and BS. The other interface is used as the gateway interface of the Wireless Access Network. According to the routing protocol of the wired network, the IP service segment processed by this SPC will be routed to the corresponding interface according to the destination IP address, so that it can be intercepted by SPC and complete the service forwarding function. For example, in Figure 2, a SPC has three network interfaces, 10.3.23.50 is used as the IP address of the SPC itself for TCP-based communication with SCC and BS, 10.72.0.0/20 and 10.72.224.0/19 are the gateway interfaces. packets destined for 10.72.0.0/20 and 10.72.224.0/19 are routed to the corresponding SPC interface.

After the system is started, BS and SPC establish connections with SCC respectively to complete the initialization process of each BS and SPC, and then SCC will issue a SPC list to each BS, notify each BS of the IP address of each SPC and the IP service scope to be processed. Each BS then establishes an IP Tunnel with each SPC. After each terminal starts up, it first scans the wireless channel to find the best BS signal as the Access Node and initiates an inbound request to the BS, the request contains information such as the device serial number, user ID, and user key. BS forwards the corresponding information to the SCC. After the SCC authentication passes, it registers the user's access base station, modify the user status, assign an IP address to the user based on user attributes, and notify the corresponding BS and terminal to complete the user's inbound process. Then the SCC determine the SPC processing the terminal service based on the allocated IP address, and notify the SPC Terminal Access location (that is, the BS address ). In the future, the SCC will push the status to the corresponding SPC in time to keep the user status in the SPC up to date.

IP packets entering the wireless network can be generated by the wireless access network terminal or nodes 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 business and forwards the complete IP packet to the SPC through the tunnel between the base station and the SPC, SPC extracts the original message from the TCP Message to the terminal. If the destination address is within the processing range, it searches for the base station where the destination address is located, the original packet is forwarded to the target base station in a tunnel mode and sent to the destination terminal through a wireless interface. Otherwise, the SPC adds a Layer 2 frame header to the original packet and forwards it to the corresponding router, the packet enters the internal network and is sent to the destination terminal or to other SPC gateway interfaces through normal routing.

According to the design process, packets entering the network outside the wireless network will be routed according to the destination address, and will inevitably be routed to a SPC gateway interface. In summary, when SPC receives an IP packet, it processes the packet according to Figure 3. When the terminal is moved, the location must be updated. To this end, the terminal continuously detects network signals. When a cell with better signal is found, the terminal initiates a switching request to the BS of the new cell. The BS responds and forwards the switching request to the SCC to update the user status, the SPC user is notified of the new location. SCC sends a switch notification to the original access zone and sends a confirmation message to the new zone.