【作者】 王雅丽；

【导师】 林生；

【作者基本信息】 华南师范大学 ， 计算机软件与理论， 2002， 硕士

【摘要】 在互联网迅速发展的今天，各种网络业务对服务质量的要求越来越高，而可供使用的网络资源却依然有限，如何解决这一供需矛盾的问题已经成为网络服务质量领域的一个研究热点。冈此，一种旨在保证IP骨干传送网上的服务质量的网络模式——“区分服务网络”应运而生，而对于实现区分服务网络的各种各样关键技术和改进，也已经成为近几年来出现的热门研究课题。 本论文在现有研究下作的基础上，提出并设计了一种构筑在区分服务网络(以下简称‘DS网络’)上的QoS Agent系统，以实现区分服务域(以下简称‘DS域’)间的业务流接纳控制和域内的网络资源管理和分配。为此，本论文阐述了QoS Agent系统的整体框架结构、各实体要素及其自适应调节机制，并从DS域内和DS域间两个角度描述了QoS Agent的网络资源分配和控制流程。 本论文还在网络模拟器NS2上实现了QoS Agent系统的主要功能，从而模拟了具有QoS Asent系统的DS域内数据传输。模拟结果表明，当整个网络的带宽资源可以满足现有数据传送请求时，带有QoS Agent的DS网络与普通DS网络比较，它们的传送性能差别不大；而当整个网络的带宽资源不能满足现有数据传送请求时(这往往正是现实网络的、人们企盼要解决的真实情况)，有QoS Agent的DS网络在保证分组传送质量和兼顾不同业务流获得带宽的公平性方面，其性能优于普通DS网络。 最后，本论文在评价了模拟实现方案和QoS Agent系统性能之后，对该系统目前仍存在的一些问题，比如QoS Agent系统的瓶颈、可靠性等问题，分析了原因并提出改进的思路。更多还原

【Abstract】 As the Internet is growing up increasingly, the QoS requirements by kinds of network traffic become more and more higher, while the available network resources are still limited. How to resolve the contradiction between the demands and the supplies has become a research highlight inQoS area. So a new network architecture------the ’Differentiated Servicesnetwork1 is introduced to ensure the QoS as transferring dataflow on the IP backbone networks.Based on the work-out of various researches currently existed, this thesis proposes a QoS Agent System, that is based on the DiffServ network, to control the traffic admissions and manage the network resources in the DS domain. The thesis also describes the architecture, the elements and the adaptive conditioning mechanism of the QoS Agent System. On the aspect of the intra-DS domain and inter-DS domain, the network resources allocation and the control of dataflows for the QoS Agent System are also discussed.This thesis has implemented partial functions of the QoS Agent System on the NS2 platform and done simulations of the data transmission in the DS-Agent domain. The results of the simulations have shown that (1) when the whole bandwidth resources can satisfy the requests of all the dataflow, the difference of transferring performance between popular DS domain and DS-Agent domain can be ignored; (2) when the whole bandwidth resources can not satisfy the requests of all the dataflow, the performance of the DS-Agent domain is much better than the popular DS domain because of its low packet lost rate and the fairness of bandwidth allocation.In the end, after evaluating the QoS Agent System and its simulation scheme, the thesis also points out some unsolved problems of QoS Agent System, such as the bottleneck and reliability of this system etc., and gives some suggestions for improving it.更多还原