Flow Control Research Based On The Priority Of Multi-Service

Internet was developed for text-oriented network applications, but with the expansion of the scale, the growing demand for the multimedia application and the development of communication technology, it faces a high-speed switching, the guarantee of the quality of service, network security and mobility challenges in many aspects. To make up for the deficiencies referred, a new network architecture called "SUPA"(Single-layer User-data switching Platform Architecture) is developed at SC-Netcom Lab (Sichuan Network Communication Key Laboratory). SUPA is based on DWDM. In order to separates User Data-platform from Signaling&Management Platform, it uses re-clarifying out-of-band signaling concept in the context of networking. It makes SUPA as a basis of backbone nodes for high-speed and high-efficient switching.Since there are more and more non-traditional data applications through the network transmission, various multimedia business occupies the proportion of larger and larger, and it causes a higher requirement for the current network environment and the quality of service. To solve the above problems according to SUPA, our lab has done some research work, but no work is done for flow control based on the priority of multi-service, which is the main task for this thesis.This thesis firstly introduces the existing classification of services and the standards and recommendations related to Ethernet flow control, and then the author studies the method of services classification and the mapping between service and priority, and finally designates a classification method and a mapping which are more suitable for SUPANET. Also the author designs two scheduling algorithms for priority-based flow control, namely strict priority-based (SP) and weighted round robin (WRR) mechanism, of which SP sends a packet in strict accordance with the order of the priority from high to low, only when there is no higher priority packet, the lower priority packets can be selected, while WRR schedules the different priority packets in turn, and ensures each kind of priority packets can obtain a certain service-time to prevent the packets with the lower priority from waiting too long to get service, which shows the fairness of this flow control mechanism. FIFO queue is just designed to compare with the priority-based multi-queue flow control mechanisms.After that, the author has studied the switching architecture and queuing models of switches, and analyzed their pros and cons, and finally selected the proper switching architecture and queuing model for this thesis, that is, Cross bar switching architecture which is internal non-blocking and virtual output queuing model which is based on VLI.At last, the author uses the OPNET network simulation software to simulate the designed flow control mechanisms, and the conclusions show the designed mechanism based on the priority of multi-service is feasible. Also having analyzed the simulation design and its relative parameter settings, the author has obtained the shortcomings of the design and figured out the next step for future research.