本文選題：分布式緩存 + 分布式傳輸　； 參考：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：本文提供了一種新的內(nèi)容分發(fā)網(wǎng)絡(luò)的架構(gòu)，即通過(guò)在網(wǎng)絡(luò)中部署具有低成本、大容量的緩存節(jié)點(diǎn)來(lái)減輕用戶(hù)下載文件對(duì)網(wǎng)絡(luò)回傳容量的造成的開(kāi)銷(xiāo)，但也引入了內(nèi)容文件的緩存、傳輸?shù)葐?wèn)題，加劇了系統(tǒng)的復(fù)雜度。因此對(duì)內(nèi)容分發(fā)過(guò)程的高效管理在內(nèi)容分發(fā)網(wǎng)絡(luò)中變的迫切且重要。 本文首先分析了內(nèi)容分發(fā)網(wǎng)絡(luò)中的分布式緩存問(wèn)題和分布式傳輸調(diào)度問(wèn)題，并且給出了針對(duì)這兩種問(wèn)題的常見(jiàn)算法。然后研究了網(wǎng)絡(luò)編碼在基于分布式緩存的內(nèi)容分發(fā)網(wǎng)絡(luò)中的應(yīng)用。即通過(guò)使用網(wǎng)絡(luò)編碼可以將文件的緩存問(wèn)題和傳輸問(wèn)題轉(zhuǎn)化成使網(wǎng)絡(luò)為每個(gè)移動(dòng)用戶(hù)保證一個(gè)相對(duì)固定且足夠大的流速率的問(wèn)題，從而為內(nèi)容文件的分發(fā)問(wèn)題建立了一個(gè)流調(diào)度的模型。利用原始-對(duì)偶的分解方法對(duì)流調(diào)度問(wèn)題進(jìn)行分解可以得到中心服務(wù)器與helper節(jié)點(diǎn)之間的緩存分配問(wèn)題和helper節(jié)點(diǎn)與移動(dòng)用戶(hù)之間的帶寬分配問(wèn)題。通過(guò)將原問(wèn)題進(jìn)行分解，每一個(gè)網(wǎng)絡(luò)節(jié)點(diǎn)可以獲得一個(gè)可以分布式運(yùn)行的子算法，各個(gè)子算法之間聯(lián)合迭代，最終得出最優(yōu)的緩存、帶寬分配。 最后，考慮到移動(dòng)無(wú)線(xiàn)環(huán)境動(dòng)態(tài)變化的馬爾科夫特性，本文中將整個(gè)網(wǎng)絡(luò)拓?fù)涞淖兓礊橐粋�(gè)有限狀態(tài)的馬爾科夫鏈，，每一種網(wǎng)絡(luò)拓?fù)涠际沁@個(gè)馬爾科夫鏈的一個(gè)平穩(wěn)分布。根據(jù)馬爾科夫狀態(tài)的平衡方程可以得到網(wǎng)絡(luò)拓?fù)涞臓顟B(tài)轉(zhuǎn)移概率和轉(zhuǎn)移周期。運(yùn)行分布式算法的節(jié)點(diǎn)可以根據(jù)這個(gè)狀態(tài)轉(zhuǎn)移概率和周期來(lái)進(jìn)行自我配置從而使整個(gè)網(wǎng)絡(luò)的性能達(dá)到全局最優(yōu)。
[Abstract]:In this paper, a new architecture of content distribution network is proposed, in which the cost of downloading files to the network is reduced by deploying a low-cost, large-capacity cache node in the network. However, some problems such as cache and transmission of content files are introduced, which aggravate the complexity of the system. Therefore, the efficient management of the content distribution process becomes urgent and important in the content distribution network. In this paper, we first analyze the distributed cache problem and distributed transport scheduling problem in content distribution networks, and give some common algorithms for these two problems. Then the application of network coding in distributed cache-based content distribution network is studied. That is, by using network coding, the problem of file caching and transmission can be transformed into the problem of making the network guarantee a relatively fixed and sufficiently large flow rate for each mobile user. Thus, a flow scheduling model is established for the distribution of content files. The problem of cache allocation between the central server and the helper node and the bandwidth allocation problem between the helper node and the mobile user can be obtained by decomposing the primal-dual decomposition method for the convection scheduling problem. By decomposing the original problem, each network node can obtain a distributed sub-algorithm that can be run, each sub-algorithm iterates together, and finally the optimal cache and bandwidth allocation are obtained. Finally, considering the Markov characteristic of the dynamic change of mobile wireless environment, the change of the whole network topology is regarded as a finite state Markov chain in this paper, and each network topology is a stationary distribution of the Markov chain. According to the equilibrium equation of Markov state, the state transition probability and transition period of network topology can be obtained. The nodes running the distributed algorithm can self-configure according to the transition probability and period of the state so that the performance of the whole network can be optimized globally.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TP393.02

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相關(guān)期刊論文 前1條

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