本文關(guān)鍵詞： 對(duì)等網(wǎng)絡(luò) 視頻點(diǎn)播 流媒體 理論建模 資源分配　出處：《重慶大學(xué)》2014年博士論文　論文類型：學(xué)位論文

【摘要】：近年來，寬帶互聯(lián)網(wǎng)的普及和多媒體技術(shù)的發(fā)展帶來了網(wǎng)絡(luò)應(yīng)用的不斷增長和豐富。其中，視頻點(diǎn)播(Video-on-Demand，VoD)業(yè)務(wù)以獲取便捷、內(nèi)容豐富等特征吸引了廣大的用戶，己成為當(dāng)今互聯(lián)網(wǎng)上的殺手級(jí)應(yīng)用。海量的媒體數(shù)據(jù)和日益增長的用戶數(shù)量使得以低成本構(gòu)建高質(zhì)量的分發(fā)體系成為視頻點(diǎn)播業(yè)務(wù)中最迫切的需求之一。P2P技術(shù)為視頻點(diǎn)播業(yè)務(wù)的進(jìn)一步發(fā)展提供了新的契機(jī)。研究如何利用P2P網(wǎng)絡(luò)中的節(jié)點(diǎn)帶寬資源來構(gòu)建高性能的視頻點(diǎn)播系統(tǒng)是當(dāng)前學(xué)術(shù)界的熱點(diǎn)。然而，點(diǎn)播用戶行為的不同步、對(duì)視頻流暢性的需求以及用戶動(dòng)態(tài)性等因素給P2P點(diǎn)播帶來很大的挑戰(zhàn)。 本文針對(duì)P2P點(diǎn)播系統(tǒng)中的資源分配技術(shù)展開深入研究，針對(duì)現(xiàn)有技術(shù)的不足，提出幾種合理的資源分配模型和高效的資源優(yōu)化技術(shù)，旨在通過合理有效地分配節(jié)點(diǎn)的帶寬資源，達(dá)到提高系統(tǒng)性能、減少跨ISP流量的目的。本文的研究工作主要包括以下三個(gè)方面： 1)提出一個(gè)基于服務(wù)器負(fù)載的模型來研究多頻道P2P點(diǎn)播系統(tǒng)中的頻道內(nèi)帶寬失衡現(xiàn)象和跨頻道帶寬失衡現(xiàn)象。該模型引入排隊(duì)網(wǎng)絡(luò)理論，能夠較好地描述節(jié)點(diǎn)的各種行為特征，比如加入系統(tǒng)、在頻道中逗留、切換頻道和離開系統(tǒng)等。該模型定義平均負(fù)載指數(shù)作為性能評(píng)價(jià)指標(biāo)，進(jìn)而分析和比較了三類可用于多頻道P2P點(diǎn)播系統(tǒng)的帶寬分配方法，即樸素分配(NaiveAllocation，NAA)方法，，獨(dú)立頻道分配(Independent-Channel Allocation，ICA)方法和跨頻道分配(Cross-ChannelAllocation，CCA)方法。通過漸進(jìn)分析的數(shù)學(xué)方法，在理論上證明了NAA方法將同時(shí)導(dǎo)致頻道內(nèi)帶寬失衡和跨頻道帶寬失衡；ICA方法能夠有效減輕頻道內(nèi)帶寬失衡但依然會(huì)導(dǎo)致跨頻道帶寬失衡；而CCA方法能夠同時(shí)減輕頻道內(nèi)帶寬失衡和跨頻道帶寬失衡。在理論分析的基礎(chǔ)上，提出一種基于CCA方法的優(yōu)化策略CCA(Z)。該策略的核心在于正在下載的節(jié)點(diǎn)在頻道內(nèi)按順序選擇鄰居以緩解頻道內(nèi)帶寬失衡，種子節(jié)點(diǎn)以跨頻道資源共享的方式來服務(wù)選中頻道的連續(xù)Z個(gè)媒體塊；這樣做能夠達(dá)到降低服務(wù)器負(fù)載的目的。通過仿真實(shí)驗(yàn)，不僅證明了理論分析的正確性，也證實(shí)了CCA(Z)在服務(wù)器負(fù)載方面具有比現(xiàn)有技術(shù)更好的性能。 2)為達(dá)到降低服務(wù)器負(fù)載、減少跨ISP流量和提高節(jié)點(diǎn)預(yù)讀取總量這三個(gè)目標(biāo)，本文提出兩種感知ISP的集中式資源分配算法。一是以最小化服務(wù)器負(fù)載為首要目標(biāo)、最小化跨ISP流量為第二目標(biāo)、最大化節(jié)點(diǎn)預(yù)讀取總量為第三目標(biāo)的服務(wù)器優(yōu)先優(yōu)化(Server-First Optimal，SFO)算法；二是以最小化跨ISP流量為首要目標(biāo)、最小化服務(wù)器負(fù)載為第二目標(biāo)、最大化節(jié)點(diǎn)預(yù)讀取總量為第三目標(biāo)的位置優(yōu)先優(yōu)化(Locality-First Optimal，LFO)算法。通過引入網(wǎng)絡(luò)流理論，這兩種算法可以轉(zhuǎn)化為一系列的最大流問題或最小費(fèi)用流問題進(jìn)行求解。仿真實(shí)驗(yàn)證明，SFO和LFO算法擁有比現(xiàn)有技術(shù)更好的性能。 3)針對(duì)SFO和LFO算法不能很好的應(yīng)用于動(dòng)態(tài)環(huán)境的問題，本文提出基于混合鄰居的線性加權(quán)和(Linear Weighted Sum with Hybrid Neighbor，LWS-HN)機(jī)制。這是一種感知ISP的分布式資源分配機(jī)制，采用一種兼顧節(jié)點(diǎn)負(fù)載均衡和流量本地性的混合鄰居選擇策略，并通過構(gòu)造一個(gè)目標(biāo)函數(shù)是服務(wù)器負(fù)載、跨ISP流量和節(jié)點(diǎn)預(yù)讀取總量三者的線性加權(quán)和的優(yōu)化問題來進(jìn)行節(jié)點(diǎn)的速率分配。針對(duì)該優(yōu)化問題提出一種分布式的求解方法，并將其轉(zhuǎn)化成一種能夠用于P2P點(diǎn)播系統(tǒng)的動(dòng)態(tài)速率分配策略，從而實(shí)現(xiàn)減輕服務(wù)器負(fù)載、減少跨ISP流量和提高節(jié)點(diǎn)預(yù)讀取總量這三個(gè)目標(biāo)或在這三個(gè)目標(biāo)出現(xiàn)沖突時(shí)達(dá)成某種平衡。仿真實(shí)驗(yàn)證明，LWS-HN機(jī)制的性能表現(xiàn)優(yōu)于現(xiàn)有技術(shù)。 本文的研究具有較高的現(xiàn)實(shí)意義和理論價(jià)值，一方面可以對(duì)P2P點(diǎn)播中的資源分配技術(shù)提供深入的認(rèn)識(shí)，另一方面可以對(duì)提高系統(tǒng)性能、降低部署成本提供有價(jià)值的參考。
[Abstract]:In recent years, the development of the popularity of broadband Internet and multimedia technology brings the rapid growth of network applications and rich. Among them, the video on demand (Video-on-Demand, VoD) business to get convenient, rich content and other characteristics to attract the majority of users, has become the killer application on the Internet. The number of media data and growing the user makes the distribution system of high quality with low cost has provided a new opportunity for further development of.P2P technology is one of the most urgent needs of VOD service for the VOD service. VOD system on how to use the bandwidth resource in P2P network to build a high performance is a hot topic in academic circles. However, not synchronized user behavior, video on demand and user flow of dynamic factors to P2P demand brought a great challenge.
This paper conducts in-depth research on resource allocation for P2P VOD system, aiming at the defects of the existing technology, the technology of resource optimization resource allocation model of several reasonable and efficient, through the rational and efficient allocation of node bandwidth resources, improve system performance, reduce the cross ISP traffic. The main research work of this paper includes the following three aspects:
1) proposed a bandwidth imbalance load model based on multi channel P2P VOD system to study the channel and cross channel bandwidth imbalance. This model introduces queuing network theory, which can describe the behavior of nodes, such as adding system, stay in the channel, the channel switching and leave the system. This model defines the load average index as the performance index, and then analyze and compare the three classes can be used for bandwidth allocation method for multi channel P2P VOD system, namely simple distribution (NaiveAllocation, NAA) method, independent channel assignment (Independent-Channel Allocation ICA) method and cross channel allocation (Cross-ChannelAllocation, CCA) method. Through mathematical method asymptotic analysis, we prove that the NAA method will also lead to imbalance of bandwidth and cross channel bandwidth imbalance channel method can effectively reduce the ICA; In the channel bandwidth imbalance but still can cause the cross channel bandwidth imbalance; while the CCA method can also reduce the channel bandwidth and cross channel bandwidth imbalance imbalance. On the basis of theoretical analysis, put forward an optimization strategy based on CCA CCA method (Z). The core of this method is under the load of the nodes in the channel at in order to alleviate the imbalance of channel bandwidth choice of neighbors within the seed node to cross channel resource sharing services to selected channel Z continuous media blocks; it can reduce server load. Through simulation experiments, not only proved the correctness of theoretical analysis is confirmed by CCA (Z) in the server load has better performance than existing techniques.
2) in order to reduce the server load, reduce the cross ISP traffic and improve the total node pre read the three objectives, proposed centralized resource allocation algorithm for two kinds of perceived ISP. One is to minimize the server load as the primary goal, to minimize the cross flow rate of ISP is second, the maximum node pre read a total of third goals server priority optimization (Server-First Optimal SFO) algorithm; two is to minimize the cross ISP traffic is the primary goal, to minimize the server load is second, and the maximum node position of pre read total third target first (Locality-First Optimal LFO) optimization algorithm. By introducing the network flow theory, the two algorithms can be transformed into the maximum flow problem of a series or the minimum cost flow problem. Simulation results show that the SFO and LFO algorithm has better performance than existing techniques.
3) for the SFO and LFO algorithms are not well applied in the dynamic environment, this paper puts forward the linear and mixed weighted neighbor based (Linear Weighted Sum with Hybrid Neighbor, LWS-HN). This is the mechanism of distributed resource allocation mechanism of a perception of ISP, using a mixture of both the neighbor node local load balancing and flow the choice of strategy, and by constructing an objective function is the server load, optimization problems and linear weighted cross ISP traffic and three of the total amount of prefetch nodes to rate allocation nodes. For the optimization problem is proposed for a distributed method, and converted it into a can be used for dynamic rate allocation strategy P2P VOD system, thereby reduce server load, reduce the cross ISP traffic and improve the total amount of the three node prefetch target or reach some kind of conflict in the three goals The simulation experiment shows that the performance of the LWS-HN mechanism is superior to the existing technology.
The research in this paper has high practical significance and theoretical value. On the one hand, it can provide an in-depth understanding of resource allocation technology in P2P on demand, and on the other hand, it can provide valuable reference for improving system performance and reducing deployment cost.

【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN948.64

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 ;Strategies of Collaboration in Multi-Swarm Peer-to-Peer Content Distribution[J];Tsinghua Science and Technology;2012年01期

2 戴伏生;包學(xué)才;韓衛(wèi)占;;服務(wù)質(zhì)量約束下的IP組播通信可靠性評(píng)估方法(英文)[J];中國通信;2011年05期

本文編號(hào)：1453465