本文選題：P2P組播 + 應(yīng)用層組播　； 參考：《山東大學(xué)》2014年碩士論文

【摘要】：近年來,隨著計算機和網(wǎng)絡(luò)技術(shù)的快速發(fā)展,越來越多的多媒體業(yè)務(wù)應(yīng)用出現(xiàn)在互聯(lián)網(wǎng)中,例如,廣播、視頻會議、遠程教育等等,這些應(yīng)用對網(wǎng)絡(luò)帶寬和延遲等都有很高的要求,組播一直被認為是一種有效的解決方案。但是IP組播具有極大的依賴性,特別是對網(wǎng)絡(luò)設(shè)備,需要對組播路徑上的設(shè)備進行升級,因此會耗費巨額資金,阻礙了IP組播的廣泛部署。這也是IP組播一直以來沒有得到廣泛應(yīng)用的原因之一。隨著應(yīng)用對網(wǎng)絡(luò)組播的迫切需求,人們提出了應(yīng)用層組播這一解決方案。 P2P技術(shù)作為應(yīng)用層的一個實際應(yīng)用也在不斷的發(fā)展�；赑2P覆蓋網(wǎng)絡(luò)具有很多優(yōu)點。因此,P2P覆蓋網(wǎng)絡(luò)的組播問題已成為學(xué)術(shù)界以及工業(yè)界研究的研究熱點。比較典型的P2P網(wǎng)絡(luò)組播有：Scribe、Chord組播、CAN-Multicast以及Bayeux。由于現(xiàn)在流媒體應(yīng)用的興起,需要傳輸?shù)臄?shù)據(jù)量很大,在P2P網(wǎng)絡(luò)上用組播或廣播的方式來進行軟件更新文件以及預(yù)測可能流行內(nèi)容的發(fā)送,從而使每個節(jié)點需要背負沉重的負載來把數(shù)據(jù)轉(zhuǎn)發(fā)給它的相鄰節(jié)點,為了減小節(jié)點以及鏈路的壓力,需要有效的限制每個節(jié)點的度數(shù)。并且對于應(yīng)用服務(wù)提供商來說希望得到一個總花費小的解決方案。因此,P2P組播在覆蓋網(wǎng)絡(luò)上傳輸內(nèi)容,即使數(shù)據(jù)沿著P2P網(wǎng)絡(luò)的生成樹來進行,并且限制樹的最大度數(shù)。這樣的一個解決方案樹被圖論中稱為是度約束最小生成樹。 在本文中,P2P應(yīng)用層組播為研究對象,重點研究了應(yīng)用層組播如何高效尋求得到一棵高效的度約束最小組播樹問題。主要工作如下： (1)在本文中,提出了一種新的方案來解決度約束最小生成樹問題,即采用了基于蟻群算法并且伴隨有局部搜索的方法。做了相關(guān)仿真實驗,并且將仿真結(jié)果與其他算法進行了比較。蟻群算法是一個通過個體尋找以及與集體合作來尋找最優(yōu)解的優(yōu)化算法,但是蟻群算法需要搜索的時間比較長,有時容易陷入局部最優(yōu),所以我們采用了基于蟻群算法并且結(jié)合局部搜索操作的算法,這種方法在很大程度上避免了算法陷入局部最優(yōu)的缺點。仿真結(jié)果表明,我們提出的新的蟻群算法相比其他的智能算法在效率上更優(yōu)。 (2)我們對蟻群算法進行了更改,該算法比傳統(tǒng)算法效率提高了很多。隨后研究了分布估計算法的特性,使我們提出的算法具有了快速收斂的性質(zhì),并且提出了基于此種算法伴有局部搜索的新方法。一方面從宏觀上來把握搜索方向,另一方面局部搜索操作避免了此算法的易早收斂,陷入局部最優(yōu)的缺點。經(jīng)過仿真實驗得知用新提出的方法來解決度約束最小生成樹問題比以往的算法在效率上都要好,說明我們提出的這種方法是可行的。
[Abstract]:In recent years, with the rapid development of computer and network technology, more and more multimedia applications appear in the Internet, such as broadcasting, video conferencing, distance education and so on. These applications have high requirements for network bandwidth and latency, multicast has been considered as an effective solution. However, IP multicast has a great dependence, especially for network devices, it needs to upgrade the devices on the multicast path, so it will cost a lot of money and hinder the extensive deployment of IP multicast. This is one of the reasons that IP multicast has not been widely used. With the urgent demand of application for network multicast, people put forward the solution of application-layer multicast, and P2P technology as a practical application of the application layer is developing constantly. P2P overlay network has many advantages. Therefore, the multicast problem of P2P overlay network has become a research hotspot in academia and industry. The typical P2P multicast networks include: Scribechord multicast CAN-Multicast and Bayeux. Due to the emergence of streaming media applications, the amount of data needed to be transmitted is very large. In P2P networks, multicast or broadcast is used to update software files and predict the transmission of popular content. In order to reduce the pressure of nodes and links, each node needs to carry a heavy load to transmit the data to its adjacent nodes. In order to reduce the pressure of nodes and links, it is necessary to effectively limit the degree of each node. And for the application service provider, the hope is to get a small total cost of the solution. Therefore, P2P multicast transmits content over overlay network, even if the data is carried out along the spanning tree of P2P network, and the maximum degree of the tree is limited. Such a solution tree is called the degree constraint minimum spanning tree in graph theory. In this paper, P2P application-layer multicast is studied, and the problem of how to find an efficient minimum multicast tree with degree constraints is studied. The main works are as follows: (1) in this paper, a new scheme is proposed to solve the degree constrained minimum spanning tree problem, which is based on ant colony algorithm and accompanied by local search. The simulation results are compared with other algorithms. Ant colony algorithm is an optimization algorithm to find the optimal solution through individual search and collective cooperation, but ant colony algorithm needs to search for a long time, sometimes it is easy to fall into local optimization. So we adopt the algorithm based on ant colony algorithm and combined with local search operation, this method largely avoids the disadvantage that the algorithm falls into local optimum. Simulation results show that the proposed new ant colony algorithm is more efficient than other intelligent algorithms. (2) We have modified the ant colony algorithm, which is much more efficient than the traditional algorithm. Then, the characteristics of the distribution estimation algorithm are studied, which makes the proposed algorithm have the property of fast convergence, and a new method based on this algorithm with local search is proposed. On the one hand, the search direction is grasped from the macro level; on the other hand, the local search operation avoids the premature convergence of the algorithm and falls into the local optimum. The simulation results show that the proposed method is more efficient than the previous algorithms to solve the degree constrained minimum spanning tree problem, which shows that the proposed method is feasible.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TP393.02;TP18

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相關(guān)期刊論文 前1條

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本文編號：2091655