【摘要】：為了適應航空航天技術的飛速發(fā)展,國際空間數(shù)據(jù)系統(tǒng)咨詢委員會(CCSDS)推出了擁有靈活多樣的數(shù)據(jù)處理業(yè)務的高級在軌系統(tǒng)(AOS)協(xié)議。隨著空間數(shù)據(jù)量的越來越大,以及數(shù)據(jù)流的自相似性的影響,空間網(wǎng)絡發(fā)生擁塞就變得不可避免。為了緩解網(wǎng)絡的擁塞,本文提出了一種基于反饋機制的主動隊列管理算法,實現(xiàn)對擁塞的有效控制。本文的主要研究的內容包括:首先,詳細介紹了高級在軌系統(tǒng)以及網(wǎng)絡流量的自相似性。網(wǎng)絡業(yè)務流量擁有著自相似的特性,這意味著傳統(tǒng)的泊松模型對自相似業(yè)務已經(jīng)不適用。本文介紹了兩種適應自相似性的業(yè)務模型:ON/OFF模型和FBM模型,并分別對它們建模和仿真。然后對處理網(wǎng)絡擁塞現(xiàn)象有很好效果的RED算法進行詳細介紹,借鑒該算法的思想對主動隊列管理算法進行改進。使用ON/OFF模型模擬自相似流量,統(tǒng)計每個信源ON狀態(tài)的持續(xù)時間,并求其平均持續(xù)時間。通過將求得的平均持續(xù)時間與設定的門限值進行比較,決定對數(shù)據(jù)包的丟棄情況,實現(xiàn)調控數(shù)據(jù)傳輸速率,緩解網(wǎng)絡擁塞的目的。最后,考慮到在引入隊列管理模塊的AOS多路復用模型中,各個模塊之間可以相互結合,實現(xiàn)系統(tǒng)在控制網(wǎng)絡擁塞方面的進一步優(yōu)化。在改進后的隊列管理算法的基礎上加入反饋機制,將虛擬信道調度模塊的幀緩存區(qū)的緊張程度反饋給隊列管理模塊,從而得到性能更加優(yōu)越的基于反饋機制的主動隊列管理算法。該主動隊列管理算法同時考慮到數(shù)據(jù)包緩存區(qū)的緊張程度和數(shù)據(jù)幀緩存區(qū)的緊張程度,并使用MATLAB軟件搭建仿真平臺進行仿真。通過評估仿真結果的各項性能指標,得出加入反饋調節(jié)的主動隊列管理算法能夠極大提高系統(tǒng)性能的結論。
[Abstract]:In order to adapt to the rapid development of aerospace technology, the International Space data system Advisory Committee (CCSDS) has launched the advanced on-orbit system (AOS) protocol with flexible and diverse data processing services. With the increasing amount of spatial data and the influence of self-similarity of data flow, congestion in spatial networks becomes inevitable. In order to alleviate network congestion, an active queue management algorithm based on feedback mechanism is proposed to effectively control congestion. The main contents of this paper are as follows: firstly, the paper introduces the self-similarity of high-level on-orbit system and network traffic in detail. Network traffic has the characteristic of self-similarity, which means that the traditional Poisson model is no longer suitable for self-similar traffic. In this paper, we introduce two kinds of business models that adapt to self-similarity, namely: one / off model and FBM model, and model and simulate them respectively. Then the RED algorithm which can deal with network congestion is introduced in detail and the active queue management algorithm is improved by using the idea of the algorithm. Using ON/OFF model to simulate self-similar traffic, the duration of each source on state is counted and its average duration is obtained. By comparing the average duration with the set threshold, the data packet dropping is determined, the data transmission rate is adjusted and the network congestion is alleviated. Finally, considering that in the AOS multiplexing model with queue management module, each module can be combined with each other to achieve further optimization in network congestion control. On the basis of the improved queue management algorithm, the feedback mechanism is added, and the tension of the frame buffer of the virtual channel scheduling module is fed back to the queue management module. Thus, an active queue management algorithm based on feedback mechanism is obtained. The active queue management algorithm considers the tension of data packet buffer and data frame buffer at the same time, and uses MATLAB software to build a simulation platform for simulation. By evaluating the performance indexes of the simulation results, it is concluded that the active queue management algorithm with feedback regulation can greatly improve the performance of the system.
【學位授予單位】：沈陽理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：V443.1;TP393.06

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本文編號：2180937