隨選視訊快取之擴展軟體定義網路設計

An Extended SDN Architecture for Video on Demand Caching

李宗穎(Tsung-Ying Li)

指導教授 ： 江為國

國立中正大學/工學院/資訊工程學系/碩士(2016年)

摘要

隨著網路使用者的增加以及使用習慣的改變，網路流量呈現爆炸性的成長。現今網路使用者可以透過網路收看高流量的多媒體影音資料，如何增加隨選視訊的使用者體驗品質就是個重要的議題。因此，網路內快取(in-network caching)的概念因應而生，網路內快取服務將資料儲存在快取伺服器中。同時，近年興起的軟體定義網路(Software Defined Network；SDN)可以藉由虛擬化的模式簡單的導入新的網路功能，程式開發人員可以使用軟體定義網路架構自行開發想要的服務。本篇論文提出擴充軟體定義網路快取服務架構(Extended SDN Cache service architecture；ESC)，將分辨封包、決定儲存、以及資料儲存的功能分散給三種元件處理，可以降低單一節點的負擔。我們新增一種擴充OpenFlow交換器(Extended OpenFlow Switch)，可代替SDN 控制器分辨收到的封包，進而降低控制器的負擔；並設計將影音檔案暫存在不同快取伺服器的儲存及傳遞機制，可增加快取服務的能力及可擴展性。本論文使用網路效能佇列分析(Queuing Delay Analysis)來分析並比較ESC、OpenCache、C-flow三個服務架構中使用者從發出請求到獲得影片檔案的延遲時間。得到的數據顯示ESC的作法的平均延遲時間較其他兩者的平均延遲時間低。

關鍵字

隨選視訊 ； 軟體定義網路 ； 網路內快取 ； 網路效能佇列分析

並列摘要

Owing to the variety of ways to view the Internet and the changes of user behavior on the Internet, the network traffic has been explosively grown in recent years. User can watch the high quality video on the Internet, it is an important issue to reduce network traffic and increase the user quality of experience (QoE). Therefore, there have been in-network caching service which cache the content which had been fetched by user in proxy server. Meanwhile, the rise of the software defined network (SDN) which can implement the network function by the virtualization function. Programmers can implement the customized network functions by the SDN architecture. In this paper, we proposed an Extended SDN Cache service architecture (ESC). ESC decomposes the function of inspect incoming traffic, make cache decision, and cache content to three network entities. This design can reduce the load of single network entity. In order to reduce the load of the SDN controller, we increase an extended OpenFlow switch which can inspect the incoming traffic. ESC design the mechanism which can cache the different part of a video in different cache server. The distributed content storage mechanism can increase the cache capability and the system flexibility. We use M/M/1 queuing model to analyze the average queuing delay time, and compare ESC queuing delay time with C-flow and OpenCache. The results in numerical analysis show that the queuing delay of ESC is shorter than the other two.

並列關鍵字

Video on Demand ； Software Defined Network ； In-network Caching ； Open vSwitch ； extended OpenFlow ； Queuing Delay Analysis

參考文獻

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