Research On The Implementation Of QoS Priority Of IP Packets In Routers

With the continuous development of network technology, both the number of users of the Internet and the number of services in the Internet has shown an explosive growth, but the network resource is limited.Therefore, how to transmit a large number of messages on the limited resources,how to satisfy the requirement of bandwidth, delay and other performance of different message,such as performance requirements, and improve the quality of service have become a key issue of IP network research. At present, an effective solution to solve this problem is QoS technology,which divides the message priority according to the characteristics of the network message, and then, the message is forwarded in a certain priority order through a kind of scheduling strategy,which improves the quality of service. In this thesis, the following research work has been done on QoS technology.Firstly, the method of packet classification and division priority is studied and improved. It is found that there are a large number of repeated rules between decision tree nodes in the existing decision tree algorithm, which consumes a large amount of storage space. In this thesis, a multiple decision tree algorithm was proposed, which divides independent rule subsets and on the basis of this, a series of methods to reduce the rule repetition and to speed up the search rate are added,greatly saves the algorithm of time and space consumption.Secondly, the priority mapping table is used to implement priority mapping to get all the priority fields, such as message forwarding, discarding, and so on, in this process, two methods of changing priority mapping are designed.Thirdly, according to the priority field, the incoming message queue and forwarding process are completed. In this process, a queue scheduling algorithm is designed and improved. In this algorithm, the new queue scheduling algorithm combined with the strict priority scheduling algorithm and weighted round robin scheduling algorithm, and packet speed limiting mechanism is joined. The algorithm overcomes the shortcomings of the original algorithm, it can change the weight of the queue to a certain extent, and improve the packet loss characteristics of the burst traffic.Finally, based on the packet classification, priority mapping and queue scheduling algorithm proposed in this thesis, the design of the QoS in the router is competed. Through the testing on NPchips in the company, the design implements the priority scheduling of IP message, and have better performance.