Study On QoS Of End System In Service-Based Network

With the rapid development of Internet, more and more applications require better network services, such as VOIP, VOD, network conference etc. However, Internet, which based on TCP/IP providing "best effort" service, cannot be able to guarantee Quality of Service (QoS). To solve this problem, there have been some network QoS technologies proposed, such as Integrated Service, Differentiated Service and Multiple Protocol Label Switch, etc. But these technologies are confined to the infrastructure of TCP/IP, there is a long way to go before they are put into practice.In order to to meet different requirements for QoS, The dissertation study carefully the feature of TCP/IP architecture and find that there are many inherent faults for supporting QoS in the layered network architecture such as TCP/IP network. Though some technologies have been proposed to support QoS in the bone network, there are a lot of problems at end-system to support QoS.New ideas have been put forward for improving QoS with the emergency of non-layer network architecture. Service unit network architecture (SUNA) is new non-layer network architecture. The dissertation explores the end-system QoS of Service-based Network system (SBNS) - a concrete implementation of SUNA, and investigates how to provide end-to-end QoS. Based on the systemic analysis of the QoS requirement of end-system, the dissertation first discusses the necessary conditions that end-system supports QoS, then studies resource control, congestion control, process scheduling and traffic shaping, etc., and brings forward some new ideas about supporting QoS at end-system. The primary innovative works of the dissertation are as follows:1. Presenting the QoS framework at the end-system of SBNS. At an end-system, there are many network applications that require different netowrk services, hence, the ability to meet different requirements of QoS must be provided by end-system. The dissertation addresses the issues about providing QoS at end-system, and presents the QoS framework at the end-system of SBNS. 2. Presenting an Extended Delay-based Congestion control Algorithm (EDCA) at end-system, and then designing corresponding service unit. On the basis of end-to-end DCA, EDCA analyses the composition of each packet's RTT more accurately, and estimates the situation of network congestion more exactly, then adjusts network traffic to avoid congestion.3. Presenting the Dynamic Adjustable Priority scheduling Algorithm (DAPA), which manages different applications to get corresponding network services at end-system. By reasonable scheduling, the flows, which need more resource, receive network services preferentially.4. Presenting a Packet-Based Adaptive Traffic-shaping algorithm (PBATS) at end-system. In view of traffic features of end system, PBATS considers matching of bit rate and packet rate, and performs better in traffic shaping while improving anti-congestion ability remarkably.5. Implementing the end-system prototype of SBNS and building up QoS testbed of SBNS end-system, on which lots of popular applications of Internet have run successfully. Based on the testbed, a conclusion can be drawn that the end-system in SBNS is able to control the QoS of applications well. Finally, the thesis discusses the method of implementing the end-system in the existing TCP/IP network.