本文關(guān)鍵詞： 內(nèi)容中心網(wǎng)絡(luò) 網(wǎng)內(nèi)緩存 緩存決策策略 緩存資源分配 概率緩存 請求影響度　出處：《北京郵電大學(xué)》2014年博士論文　論文類型：學(xué)位論文

【摘要】：隨著流媒體等新業(yè)務(wù)在互聯(lián)網(wǎng)流量中所占比重不斷增加,以及云計算、物聯(lián)網(wǎng)、社交網(wǎng)絡(luò)等新型網(wǎng)絡(luò)的出現(xiàn),使得互聯(lián)網(wǎng)應(yīng)用從以面向主機的端到端通信模式為主轉(zhuǎn)向以用戶驅(qū)動的信息內(nèi)容獲取為主,而現(xiàn)有的覆蓋網(wǎng)分發(fā)技術(shù)CDN、P2P在信息傳送時,存在大量的重復(fù)內(nèi)容傳輸,嚴(yán)重影響了傳送效率。 面對互聯(lián)網(wǎng)在數(shù)據(jù)傳輸方面的可擴展性問題,以及在移動性、安全性等方面的諸多挑戰(zhàn)。學(xué)術(shù)界提出了具有革命性的信息中心網(wǎng)絡(luò)(ICN)體系結(jié)構(gòu),其中內(nèi)容中心網(wǎng)絡(luò)CCN則是一種具有里程碑式的ICN架構(gòu)。CCN把內(nèi)容當(dāng)成最基本的實體,數(shù)據(jù)內(nèi)容有一系列的內(nèi)容塊構(gòu)成,每個內(nèi)容塊都有一個唯一的分級命名標(biāo)識,并且每個內(nèi)容塊都由一個塊級別興趣包來請求。通過對內(nèi)容統(tǒng)一標(biāo)識進行定位、路由和傳輸。CCN從根本上改變了數(shù)據(jù)包的封裝結(jié)構(gòu)和尋址方式,從關(guān)注地址和主機到關(guān)注內(nèi)容本身。 CCN架構(gòu)的重要特征之一便是利用泛在化、透明化的網(wǎng)內(nèi)緩存提高用戶驅(qū)動的內(nèi)容獲取的傳輸效率和網(wǎng)絡(luò)資源的利用率,網(wǎng)內(nèi)緩存策略對于CCN的性能具有非常大的影響。然而,CCN緩存所具有的透明化、泛在化和細(xì)粒度化等新特征使傳統(tǒng)的緩存理論、方法和模型均無法直接應(yīng)用到CCN的緩存系統(tǒng)中,這對CCN緩存的相關(guān)研究均提出了新的挑戰(zhàn)。 本論文選擇內(nèi)容中心網(wǎng)絡(luò)數(shù)據(jù)傳輸?shù)目蓴U展性問題作為研究切入點,著重研究網(wǎng)內(nèi)緩存最優(yōu)決策策略和緩存資源分配這兩個具體問題。這對于提高緩存系統(tǒng)性能,合理利用緩存和帶寬資源具有重要的意義。本文的工作及貢獻主要包括以下三點。 1.提出基于節(jié)點狀態(tài)和內(nèi)容需求度的網(wǎng)內(nèi)緩存決策策略。 首先,將網(wǎng)絡(luò)節(jié)點狀態(tài)作為主要衡量標(biāo)準(zhǔn),提出基于節(jié)點介數(shù)和緩存替換率的緩存策略BetwRep。綜合使用網(wǎng)絡(luò)節(jié)點介數(shù)和節(jié)點緩存內(nèi)容更替速率,作為緩存決策度量,通過權(quán)衡節(jié)點位置重要性和緩存內(nèi)容時效性,實現(xiàn)回傳內(nèi)容的最佳放置。該策略既有效保證了內(nèi)容盡量緩存在相對重要的節(jié)點上,又能通過節(jié)點的內(nèi)容替換率來調(diào)控內(nèi)容的緩存,使重要節(jié)點避免處于高頻率的內(nèi)容替換狀態(tài)而導(dǎo)致系統(tǒng)性能下降。 其次,綜合考慮節(jié)點狀態(tài)和內(nèi)容需求度即節(jié)點內(nèi)容的受歡迎程度,基于重要的節(jié)點盡量緩存流行度高的內(nèi)容的思想,設(shè)計請求內(nèi)容返回路徑上節(jié)點的概率緩存策略ST-REQ。該策略通過計算內(nèi)容請求命中時在路徑上每個節(jié)點上被緩存的概率,內(nèi)容返回時節(jié)點按各自的概率進行內(nèi)容緩存。 2.提出基于灰色關(guān)聯(lián)分析的多參數(shù)緩存決策策略。 由于CCN中興趣包請求具有聚合特性,相對重要的節(jié)點,可能收到的請求數(shù)較少,直接利用收到的請求數(shù),無法衡量節(jié)點的重要性。針對這個問題本文定義了一個新型的網(wǎng)絡(luò)狀態(tài)度量參數(shù)——節(jié)點影響度RID,根據(jù)節(jié)點到達請求數(shù)、節(jié)點的位置以及請求的命中率來區(qū)分內(nèi)容分發(fā)路徑上節(jié)點的重要性。 隨后,綜合考慮節(jié)點影響度、流量、興趣包所經(jīng)過的跳數(shù)和節(jié)點緩存更替率這四個網(wǎng)絡(luò)系統(tǒng)參數(shù),基于灰色關(guān)聯(lián)分析決策法提出了多參數(shù)維度的緩存策略GRAD。緩存系統(tǒng)判決在路徑上哪些節(jié)點需要緩存該返回內(nèi)容時,既考慮節(jié)點的狀態(tài)、重要性、拓?fù)湫畔?又要考慮網(wǎng)絡(luò)中流量的分布。并且在GRAD決策策略中利用層次分析法來確定不同參數(shù)的權(quán)重。 3.提出分別基于請求影響度和能耗的節(jié)點緩存空間分配策略,并分析緩存判決策略對緩存資源分配的影響。 為解決有限的緩存資源的分配問題,首先以本文中定義的節(jié)點影響度為比例系數(shù),提出一種節(jié)點緩存資源的分配策略,相比節(jié)點緩存大小平均分配的方案,該策略降低了路由擴展度,并提高了網(wǎng)內(nèi)命中率。 隨后,建立以總能耗為目標(biāo)函數(shù)的緩存資源分配優(yōu)化模型,該模型是一個整數(shù)線性規(guī)劃問題。并利用遺傳算法來求解,以獲得(近似)最優(yōu)的緩存決策策略,從而實現(xiàn)(近似)最優(yōu)的緩存資源分配策略。 最后,本文通過仿真分析了基于不同緩存判決策略的緩存資源分配方案對于緩存系統(tǒng)性能的影響。
[Abstract]:With streaming media and other new business accounts for increasing the proportion of Internet traffic, and cloud computing, networking, social networks and other new network, the Internet application from the host oriented end-to-end communication mode to the information content to user driven access, while the existing overlay network distribution technology CDN P2P in information transmission, transmission has a lot of topics, seriously affect the transmission efficiency.
In the face of the Internet data transmission scalability problems, and many challenges in mobility, security and other aspects. The academic circles put forward the revolutionary Information Center Network (ICN) architecture, which content center network CCN is a milepost type with ICN architecture.CCN content as the most basic entity. The data content of a series of content blocks, each block has a unique domain name logo, and each piece of content by a block level packet to request interest. Based on the content of unified logo positioning, routing and transmission of.CCN has changed the data package structure and addressing mode fundamentally. From the address and the host to focus on the content itself.
One of the important features of the CCN architecture is the use of ubiquitous network, using transparent cache to improve the user driven content to obtain the transmission efficiency and the rate of cyber source, network caching strategy has great effect on the performance of CCN. However, transparent CCN cache with the new features in the pan and fine-grained to cache the traditional theories, methods and models are not directly applied to the cache in the CCN system, the research of the CCN cache are presented new challenges.
The center content data transmission network scalability problem as the research starting point, focuses on the optimal decision strategy in network caching and distribution of the two specific problems to improve the cache cache resources. The performance of the system, is of great significance to the rational use of cache and bandwidth resources. The work and contributions of this paper include the following three point.
1. an intra network caching decision strategy based on node state and content requirement is proposed.
First of all, the network node status as the main measure, proposed replacement rate betweenness and cache replacement rate BetwRep. cache strategy integrated use of network nodes and node betweenness based on cache content, as caching decision metric, by weighing the importance of node location and storage content timeliness, the best placed to achieve return content. This strategy not only effectively to ensure the content as far as possible in the relative importance of node cache, and to regulate the content through the contents of a node cache replacement rate, to avoid an important node in the high frequency content and lead to system performance degradation to replace state.
Secondly, considering the node status and content requirements of the popularity of node content, important nodes to cache more popular content based on the idea of the design request probability caching strategy ST-REQ. content return nodes on the path of the strategy by calculating the content of each request hit on the path node cached content probability. Return the node cache content according to their probability.
2. a multi parameter caching strategy based on grey relational analysis is proposed.
The CCN request packet with interest polymerization characteristics, the relative importance of nodes, may receive the number of requests is less, the number of requests received directly by the importance of not measure nodes. This paper defines a new network node - state metric parameters influence degree RID, according to the node number of requests arrived, the hit rate of node the location and the request to distinguish the content distribution of nodes on the path of importance.
Then, considering the effect of node degree, flow through the interest packet hops and node cache replacement rate of the four system parameters, based on Grey Relational Analysis and decision method is proposed decision caching strategy GRAD. caching system of multi parameter dimension on the path which nodes to cache the content returned, not only consider the node state and the importance of topology information, but also consider the distribution of network traffic. And using the AHP to determine the weight of different parameters in the GRAD strategy.
3. a node cache spatial allocation strategy based on the request impact degree and energy consumption is proposed, and the impact of caching decision strategy on the allocation of caching resources is analyzed.
For the problem of distribution cache with limited resources, the impact of node in this paper firstly defined as proportional coefficient, proposed a resource allocation strategy of node cache, node cache size compared to the average allocation scheme, this strategy reduces the routing extension of network and improve the hit rate.
Then, a caching resource allocation optimization model with total energy consumption as the objective function is established. The model is an integer linear programming problem. Genetic algorithm is applied to obtain the (approximate) optimal cache decision strategy, so as to achieve (approximate) the optimal allocation strategy of caching resources.
Finally, the impact of caching resource allocation scheme based on different cache decision strategies on the performance of caching system is analyzed by simulation.

【學(xué)位授予單位】：北京郵電大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TP393.02

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本文編號：1534242