网络服务系统的动力学建模与分析研究
发布时间：2019-03-31 14:07
【摘要】：本世纪初,随着对等网络(peer-to-peer, P2P)技术在因特网上广泛应用,其良好的扩展性以及较高的资源利用率等优点影响着网络技术的发展,网络发展的趋势也从集中式系统逐步向分布式系统过渡。如今,文件共享、即时通信、社交网络以及在线视频点播等网络服务系统遍布网络,影响着人们的生活、工作以及学习等各个方面。以BitTorrent为代表的P2P文件共享系统通过充分利用其中各用户节点的带宽资源、存储空间来实现文件的共享,而以在线视频点播(如优酷、土豆以及爱奇艺等)为代表的流媒体服务系统通过采用内容分发网络(Content Distribution Network, CDN)技术将服务部署到距离用户仅有“一跳”的网络边缘,并通过采用P2P技术加强边缘服务器之间的交互,从而可以提高服务质量、增大系统吞吐量和降低服务提供商部署成本。本文将着重研究网络服务系统中两种典型系统：BitTorrent和流媒体服务系统。通过分析研究这两种系统的结构、主要流程以及主要影响因素,并将各因素进行数学描述,建立其动力学模型,描述系统的动态演化过程,并进行具体的模型分析以揭示影响系统演化的各因素之间的相互关系以及对系统整体性能的影响,为网络服务系统的研究、设计以及实现提供理论支持。 本文首先分析了BitTorrent和流媒体服务系统的结构、主要流程以及影响它们动态演化的主要因素,然后分别对这两种系统进行动力学建模,并在动力学模型的基础上,对流媒体服务系统的稳定性进行讨论。本文的主要工作与创新性表现在以下几个方面： 第一,建立了BitTorrent文件共享系统的动力学模型。BitTorrent文件共享系统是P2P系统的典型应用,用户在享受下载的同时还向其他用户提供上传,充分体现P2P系统的对等性和交互性。以往针对BitTorrent的建模研究着重于全系统范围内的节点数目的变化,将影响系统变化(尤其是节点数目的变化)的主要因素归结于带宽资源的限制,忽略了其他因素对于BitTorrent系统的影响,本文采用在较小尺度上针对BitTorrent系统中单个节点的动态演化过程进行建模分析,将影响BitTorrent用户之间交互演化过程的硬件条件、文件属性、用户行为以及算法策略等因素进行数学描述,建立其动力学微分方程模型。该模型能够准确描述各因素对于BitTorrent系统中节点间交互过程的影响,同时也反映了各因素之间的相互影响关系。 第二,建立了流媒体服务系统的动力学模型。传统的针对流媒体服务系统的研究侧重于单纯算法策略的研究,而忽略了系统自身的演化过程以及这些算法策略之间的相互影响。本文首先对流媒体服务系统结构进行抽象化描述,用虚拟服务节点代表流媒体服务系统覆盖网络中的边缘服务子系统,进而将流媒体服务系统抽象成一个由虚拟服务节点组成的逻辑网络；然后分析影响虚拟服务节点与用户以及与其他虚拟服务节点交互过程中的影响因素,主要包括硬件条件、用户行为、服务属性以及算法策略等因素,并将这些影响因素进行数学描述,建立流媒体服务系统的动力学微分方程模型。该模型能够准确刻画用户接入到服务系统,以及服务子系统之间的交互过程,并能够反映各因素之间的相互关系以及他们对于系统整体性能的影响。 第三,提出了流媒体服务系统中边缘服务子系统的状态稳定性判据。边缘服务子系统距离用户仅有“一跳”之遥,是直接面向用户的服务提供者,其稳定性将直接影响用户的体验。本文从边缘服务子系统的整体性以及其运行实际意义出发,定义了边缘服务子系统的稳定性状态,并在边缘服务子系统的动力学模型的基础上,分析得到了边缘服务子系统状态的稳定性判据。 第四,提出了一种基于边缘服务子系统状态稳定性判据的接入控制算法。接入控制是边缘服务子系统的重要组成成分,控制着用户行为对于系统的影响。本文在上述稳定性分析的基础上,对流媒体服务系统提出了一种接入控制算法。当服务请求到达时,首先判断边缘服务子系统当前状态的稳定性,若当前状态为稳定状态,则接入请求；否则拒绝接入直到当前状态变为稳定状态。
[Abstract]:At the beginning of this century, as the peer-to-peer (P2P) technology is widely used on the Internet, its good expansibility and higher resource utilization rate have an influence on the development of the network technology, and the trend of network development is also gradually transited from the centralized system to the distributed system. Today, network services such as file sharing, instant messaging, social networking, and on-line video on demand have spread across the network, affecting people's life, work, and learning. The P2P file sharing system, represented by BitTorrent, realizes the sharing of files by making full use of the bandwidth resources and storage space of each user node, and on-line video on demand (such as Youku, The streaming media service system represented by the potatoes, and the like) is used to deploy the service to only the "one-hop" network edge of the user by adopting the Content Distribution Network (CDN) technology, and the interaction between the edge servers is enhanced by adopting the P2P technology, So that the service quality can be improved, the system throughput can be increased, and the deployment cost of the service provider can be reduced. This paper will focus on two typical systems in network service system: BitTorrent and streaming media service system. The structure, main flow and main influencing factors of the two systems are analyzed, and the factors are described mathematically, the dynamic model of the system is established, and the dynamic evolution of the system is described. And the concrete model analysis is carried out to reveal the mutual relationship between various factors which influence the evolution of the system and the effect of the overall performance of the system, and provide theoretical support for the research, design and implementation of the network service system. This paper first analyzes the structure, main flow of BitTorrent and streaming media service system, and the main factors that affect their dynamic evolution. Then, the two systems are modeled dynamically, and the stability of the streaming media service system is discussed on the basis of the dynamic model. The main work and innovation of this paper are the following Face: First, the power of the BitTorrent file sharing system is established The BitTorrent file sharing system is a typical application of the P2P system. Interactivity. The previous modeling research for BitTorrent focuses on the change of the number of nodes in the system-wide range. The main factors that affect the change of the system, especially the change of the number of nodes, are attributed to the limitation of the bandwidth resources, and the other factors are ignored for the BitTorrent system. In this paper, the dynamic evolution process of a single node in a BitTorrent system is modeled and analyzed on a small scale, and the hardware conditions, file attributes, user behavior, and algorithm strategy of the interaction evolution process among the BitTorrent users are analyzed. To set up its dynamics differential The model can accurately describe the influence of each factor on the inter-node interaction process in the BitTorrent system, and also reflects the mutual shadow between the factors. in response to the relationship, a streaming media service system is established The traditional research on the streaming media service system is focused on the research of the simple algorithm strategy, and the evolution of the system itself and the strategies of these algorithms are ignored. In this paper, the structure of the streaming media service system is abstracted, the edge service subsystem in the network is covered by the virtual service node, and the streaming media service system is abstracted into a virtual service node. The logic network of the virtual service node and the user as well as the interaction with other virtual service nodes is analyzed, and the factors such as hardware condition, user behavior, service attribute and algorithm strategy are mainly included. The Mathematical Description of the Line and the Establishment of the Dynamics of the Streaming Media Service System the model can accurately depict the interaction process between the user and the service system and the service subsystem, The third part is to put forward the edge service sub-system in the streaming media service system. State stability criteria. The edge service subsystem is only a short "one-hop" from the user and is a direct user-oriented service provider whose stability will be direct This paper, based on the integrity of the edge service subsystem and its operational practical significance, defines the stability state of the edge service subsystem, and analyzes the edge service subsystem form on the basis of the dynamic model of the edge service subsystem. The stability criterion of the state is presented, and the state stability of the edge-based service subsystem is presented. The access control is an important component of the edge service subsystem, which controls the user. The influence of behavior on the system is presented in this paper. On the basis of the above-mentioned stability analysis, the convective media service system The invention relates to an access control algorithm, when a service request arrives, firstly, the stability of the current state of the edge service subsystem is judged, and if the current state is in a stable state, the access request is accessed; otherwise, the access is refused until when the service request is in a stable state,
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TP393.09
本文编号：2450987
[Abstract]:At the beginning of this century, as the peer-to-peer (P2P) technology is widely used on the Internet, its good expansibility and higher resource utilization rate have an influence on the development of the network technology, and the trend of network development is also gradually transited from the centralized system to the distributed system. Today, network services such as file sharing, instant messaging, social networking, and on-line video on demand have spread across the network, affecting people's life, work, and learning. The P2P file sharing system, represented by BitTorrent, realizes the sharing of files by making full use of the bandwidth resources and storage space of each user node, and on-line video on demand (such as Youku, The streaming media service system represented by the potatoes, and the like) is used to deploy the service to only the "one-hop" network edge of the user by adopting the Content Distribution Network (CDN) technology, and the interaction between the edge servers is enhanced by adopting the P2P technology, So that the service quality can be improved, the system throughput can be increased, and the deployment cost of the service provider can be reduced. This paper will focus on two typical systems in network service system: BitTorrent and streaming media service system. The structure, main flow and main influencing factors of the two systems are analyzed, and the factors are described mathematically, the dynamic model of the system is established, and the dynamic evolution of the system is described. And the concrete model analysis is carried out to reveal the mutual relationship between various factors which influence the evolution of the system and the effect of the overall performance of the system, and provide theoretical support for the research, design and implementation of the network service system. This paper first analyzes the structure, main flow of BitTorrent and streaming media service system, and the main factors that affect their dynamic evolution. Then, the two systems are modeled dynamically, and the stability of the streaming media service system is discussed on the basis of the dynamic model. The main work and innovation of this paper are the following Face: First, the power of the BitTorrent file sharing system is established The BitTorrent file sharing system is a typical application of the P2P system. Interactivity. The previous modeling research for BitTorrent focuses on the change of the number of nodes in the system-wide range. The main factors that affect the change of the system, especially the change of the number of nodes, are attributed to the limitation of the bandwidth resources, and the other factors are ignored for the BitTorrent system. In this paper, the dynamic evolution process of a single node in a BitTorrent system is modeled and analyzed on a small scale, and the hardware conditions, file attributes, user behavior, and algorithm strategy of the interaction evolution process among the BitTorrent users are analyzed. To set up its dynamics differential The model can accurately describe the influence of each factor on the inter-node interaction process in the BitTorrent system, and also reflects the mutual shadow between the factors. in response to the relationship, a streaming media service system is established The traditional research on the streaming media service system is focused on the research of the simple algorithm strategy, and the evolution of the system itself and the strategies of these algorithms are ignored. In this paper, the structure of the streaming media service system is abstracted, the edge service subsystem in the network is covered by the virtual service node, and the streaming media service system is abstracted into a virtual service node. The logic network of the virtual service node and the user as well as the interaction with other virtual service nodes is analyzed, and the factors such as hardware condition, user behavior, service attribute and algorithm strategy are mainly included. The Mathematical Description of the Line and the Establishment of the Dynamics of the Streaming Media Service System the model can accurately depict the interaction process between the user and the service system and the service subsystem, The third part is to put forward the edge service sub-system in the streaming media service system. State stability criteria. The edge service subsystem is only a short "one-hop" from the user and is a direct user-oriented service provider whose stability will be direct This paper, based on the integrity of the edge service subsystem and its operational practical significance, defines the stability state of the edge service subsystem, and analyzes the edge service subsystem form on the basis of the dynamic model of the edge service subsystem. The stability criterion of the state is presented, and the state stability of the edge-based service subsystem is presented. The access control is an important component of the edge service subsystem, which controls the user. The influence of behavior on the system is presented in this paper. On the basis of the above-mentioned stability analysis, the convective media service system The invention relates to an access control algorithm, when a service request arrives, firstly, the stability of the current state of the edge service subsystem is judged, and if the current state is in a stable state, the access request is accessed; otherwise, the access is refused until when the service request is in a stable state,
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TP393.09
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