Research And Implementation Of Traffic Control Policy Of High-end Routers Based On Network Processor

With the rapid development of network technology, various services such as video and audio assume the detonation-like growth. The network traffic gradually expands. This puts forward higher requirement on the performance of distributed routers, so it is vital to solve the congestion-control problems.The data-handling capacity of traditional network equipment can not meet the development needs of internet data flow's fast transmission. Distributed routers based on network processor (NP) use the new scheme that network processor and switches are combined to improve the processing ability of the whole system. The network processor is a specialized integrated circuit of programmability, highly scalability and fast data packets processing capacity, which is designed for a special field about network applications. This new scheme makes it possible to use a combination of hardware and software to solve the internal traffic-control problem of distributed high-end routers.In order to solve the internal traffic-control problem of distributed high-end routers using a combination of hardware and software, the NP routers and traffic-control algorithms are used as the basis of study, and the faults of traditional congestion-control schemes are analyzed. This thesis is starting with the distributed high-end routers. Firstly, the system architecture and design principle of distributed high-end routers are introduced, the features of network processor are outlined, especially the aspects of data packet processing and the traffic of network processor are researched. The further and detailed analysis is made on the common flow control processing algorithms, including RED, WRED, SRTCM. TRTCM, leaky bucket and token bucket algorithm, and queue management and queue scheduling algorithms. The congestion points that possibly appear in the distributed routers based on NP are pointed out. According to the system architecture and design principle of distributed routers, a new traffic-control policy about high-end routers based on NP that combines in-band traffic control and out-of-band traffic control is proposed. The key technologies dealing with the congestion are designed, and the key steps and key algorithms to implement the congestion-control scheme are specified. These key technologies include the TM topology, OAM frame message, in-band traffic control and out-of-band traffic control frame messages, WRED and WFQ mechanisms, and the counter allocation scheme.Finally, the new traffic-control scheme about high-end routers based on NP is tested and verified, and the experiment test results show that the scheme provided in this thesis reasonably solves these problems about the internal congestion of high-end routers and shortcomings of switch fabric in the aspects of QoS and end-to-end traffic control, allows the router to forward packets at wire speed, and improves the integral performance of routers.