| 摘要: | 網路串流取代過去傳輸多媒體方式，檔案不須完整下載後就能即時播放，目前網路串流支援語音、影音、資料，同時支援三者傳送稱為Triple-Play Service，而IP-based TV Streaming 串流服務就屬於該服務的一種。因此本子計畫主深入探討議題以IP-based TV 串流服務為主軸，並擬提出一個行動異質網路下以串流服務等級協議 (Service Level Agreement；SLA) 為基礎可自動補償之服務管理系統。SLA 是自然語言所撰寫的文件是一種使用者於服務提供者之間的協商合約，並經由人工的方式來產生與監控，可應用於網際服務的品質控管上。補償是藉由SLA 協議擬定違反參數與參數門檻，服務管理系統一旦發現即將違反時，可事前或事後對於違反參數進行改善的措施，例如：串流服務封包遺失率 (Packet Lose Rate) 高時，改進的策略可以是提升頻寬或更改其它繞送路徑等多方面著手。本子計畫之 SLA 協議參數將包括服務品質 (Quality of Service；QoS) 與經驗品質 (Quality of Experience；QoE)，所謂的QoE 是一種指標用於量測用戶對於使用服務後的滿意度，例如：對於頻道切換的速度是否滿意。當串流服務開始時，本子計畫之管理系統會監控該串流服務是否滿足SLA 所簽署的QoS/QoE 參數，一旦違反則立刻根據現有網路資源擬定補償決策。除此之外，本系統可對串流服務預先做補償的動作，使得串流服務的品質符合協議規定的範圍，進而能夠讓用戶持續的使用高品質的串流服務，同時服務提供者能在符合SLA 協議情況下提升較多用戶數，以獲取最大的利益。本子計畫第一年將針對行動異質網路環境中串流服務之 QoS/QoE 進行監控，考量網路層與應用層的增益對於QoS/QoE 的影響，並根據SLA 協議擬定的補償策略，藉此改善QoS/QoE 之指標參數，使服務從資料彙集、統計、決策到執行提供更完善的服務品質監控。本子計畫第二年，將針對Peer-to-Peer 之網路環境中串流服務之QoS/QoE 進行監控，本子計畫擬提出QoS/QoE 之監控代理人並佈署於P2P 網路中。一般用戶可化身為監控代理人協助QoS/QoE 之監測，藉此分散管理系統之管理負擔，其管理功能將整合第一年計畫成果。一旦發現違反SLA 或即將違反SLA 指標參數時，則自動回報管 C011 共 4 頁第 2 頁理系統，管理系統可根據現有網路資源擬訂補償策略。例如：偵測畫面連續性不足時，則可從提升網路頻寬、降低抖動率 (Jitter)、編碼機制效能、編碼類型等不同層級來提供補償。 ; The transmission of multimedia technology is substituted by streaming that delivering media, such as audio and video, over Internet in real time since receiver can play it even the multimedia download is not finish yet. The commercial bundling of video, audio and Internet access is referred to as triple-play service, the one of the well-known is IP-based TV supported by streaming transmission. This sub-project focuses on the IP-based TV streaming service and proposes an auto-compensation of SLA-based Web services management system in mobile heterogeneous networks. Service Level Agreement (SLA) contract usually made with natural languages and handled by human, is a negotiated agreement between two parties where one is the customer and other is the service provider, as well as the Quality of Service is guaranteed to the customers. Compensation for Web services is when the service provider violates the contract or the quality of service decrease. For instance, service packets lose rate gets high, the management system compensates the service for more bandwidth or router other high-performance path to improve the quality of service. In this sub-project, the metrics of quality in the SLA contract is including quality of service (QoS) and quality of experience (QoE) which is a subjective measure of a customer's experiences, such as customer impression of channel zapping time, with a vendor. When service provider supplies the streaming service to customer, the management system monitors the QoS/QoE metrics with SLA contract, and the compensation is considered a violation of the SLA. The compensation policy comprises precaution and post-compensation, precaution also called pre-compensation used to keep the high quality of QoS/QoE for streaming transmission. Furthermore, the streaming service provider is able to service more customers and the QoS/QoE metrics fitted SLA contract. Finally the service provider gained a lot of profit due to this sub-project. The first year, the purpose of this sub-project is to design and research the management system by monitoring the streaming QoS/QoE metrics of SLA in mobile heterogeneous networks. We also consider the impact of the application layer and network layers on QoS/QoE, and draft the compensation policy according to the SLA contract and network state. The benefit of is this architecture can improve and guarantee the quality of streaming service through service collection state, statistics, and policy decision. The second year, this sub-project extend the pre-research to mobile peer-to-peer (P2P) networks, and the management system monitors QoS/QoE metrics. In P2P networks, the customers could be client of streaming service or agent which cooperating with management server and monitoring the neighbor for reducing the overhead in management. The agent monitors periodically the QoS/QoE metrics of neighbor and reports automatically to management server, if the violation is detected. Finally, management server makes decision on compensation policy base on the SLA contract. For example, if system detects the violation ; 研究期間 9808 ~ 9907 |
