基于多Agent流媒体传输网络拥塞控制机制的研究

发布时间：2018-01-19 06:06

本文关键词： 多Agent流媒体拥塞控制 TCP-Reno TCP-Vegas JADE　出处：《青岛科技大学》2011年硕士论文　论文类型：学位论文

【摘要】：Internet的迅猛发展和普及为流媒体业务发展提供了强大的市场动力。流媒体技术广泛用于多媒体新闻发布、网络广告、在线直播、电子商务、远程教育、实时视频会议等互联网信息服务的方方面面。它结束了传统Internet只能显示文字和图片的时代,开创了集声音、视频、文字及图像于一体的新纪元。流媒体传输技术由于自身传输时延敏感性,半可靠性,传输速率的平稳性等特点,在实际使用中通常采用UDP/IP协议进行传输。但UDP缺乏拥塞控制机制,拥塞发生时它不会降低数据发送速率,这样会引发两种情况:其一, UDP占用的资源将远高于TCP流等响应流所占用的资源,造成了严重不公平性;其二,它将导致拥塞情况的进一步恶化,甚至引发拥塞崩溃,严重影响流媒体服务质量。因此,必须对流媒体传输引入拥塞控制机制。传统拥塞控制算法是通过丢弃数据包后,使发送端通过收到大于等于三个重复的ACK或者重传计时器超时的方式隐式的判断拥塞的发生。本文将利用Agent技术实现拥塞的检测、控制和管理,并提出一种改进的拥塞控制算法Vegas-A+。当拥塞发生时,检测拥塞Agent将实时监测网络并报告拥塞的发生,并由控制拥塞Agent根据网络拥塞情况选择合适的拥塞控制算法来缓解或消除拥塞。利用Agent之间的协作,降低丢包率,提高网络的利用率。 Agent是一个具有自适应性和智能性的软件实体,能代表用户或者其它程序,以主动服务的方式完成一项任务。它具备自主性、反应性、社会性、主动性和适应性等。本文提出用检测Agent来完成报告拥塞发生的功能;控制Agent来完成减轻或消除拥塞的功能;黄页Agent来实现Agent服务公布、服务查询和服务订阅的功能。各个Agent之间相互协作形成一个多Agent系统为网络提供服务。在对Agent功能的分析和设计基础之上,利用JADE开发平台开发多Agent系统使之实现拥塞控制功能。
[Abstract]:The rapid development and popularization of Internet provides a strong market momentum for the development of streaming media business. Streaming media technology is widely used in multimedia news release, online advertising, online broadcast, electronic commerce, distance education, real-time video conferencing and other aspects of Internet information services. It is over the traditional Internet can only display text and pictures of the era. A set of voice, video, text and image in the new era of development.
Streaming media transmission technology because of its transmission delay sensitive, half reliability, transmission rate stationarity characteristics, in the actual use of the UDP/IP protocol is usually used for transmission. But the lack of UDP congestion control mechanism, it does not reduce the data transmission rate of congestion occurs, it will lead to two kinds of situations: first, UDP occupation the resources will be much higher than the TCP stream flow response resources, causing serious unfairness; secondly, it will lead to further deterioration of the situation of congestion, and even lead to congestion collapse, seriously affecting the quality of streaming media service. Therefore, must introduce the congestion control mechanism for streaming media transmission. The traditional congestion control algorithm is by discarding packets after the sender received by greater than or equal to three repeat ACK retransmission timer timeout or congestion judgment way implicit occurred. This paper will use Agent technology to realize congestion The detection, control and management, and put forward an improved congestion control algorithm Vegas-A+. when congestion occurs, Agent will be real-time monitoring of network congestion detection and report the occurrence of congestion, and the congestion control of Agent network congestion according to appropriate congestion control algorithm to alleviate or eliminate congestion. The collaboration between Agent, reduce the packet loss rate and improve network utilization.
Agent is an adaptive and intelligent software entity can, on behalf of the user or other programs to accomplish a task by the way of initiative service. It has autonomy, reactivity, sociality, initiative and adaptability. This paper proposes the use of Agent to complete the inspection report the congestion control Agent function; to reduce or eliminate the congestion function; Agent pages to achieve Agent service publication, service query and service subscription function. Each Agent cooperate with each other to form a multi Agent system to provide services to the network. On the basis of the analysis and design of Agent function based on the development platform of JADE multi Agent system development to achieve congestion the control function.

【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TP393.06

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