延遲保證 P2P 影音遞送系統之 Peer 架構研製

The Design and Implementation of Peer Structure for a P2P Video Streaming Delivering System with Guaranteed Latency

李宗祐(Zong-Yo Li)

指導教授 ： 黃能富

國立清華大學/電機資訊學院/通訊工程研究所/碩士(2013年)

https://doi.org/10.6843/NTHU.2013.00752

摘要

中文摘要
在現今的網路中，點對點網路傳輸(P2P Network)的應用已經越來越廣泛了，點對點網路傳輸的出現，最重要的是可以節省主要伺服器頻寬的負擔降低成本，然而以一個現場轉播的串流來說，延時是會直接影響到使用者經驗重要的一環。在一般的大規模現場轉播利用P2P系統，其延時並非相當的重要，但若是在線上視訊會議系統，其延時必須嚴格控制在數秒之內，以達到可互動的效果。
在本篇論文提出了一個網狀P2P拓樸的系統和其運作的演算法，並且在現實的環境中實作出這個系統的客戶端，我們稱此系統為LLP2P (Low-Latency Peer-to-Peer Network)。此系統的特性是，能夠在指定的延時下盡可能的最小化伺服器的頻寬輸出。除此之外當某些用戶在其父節點網路品質不穩定的狀況下，還提供了一連串的偵測法則和救援演算法機制，使的用戶的視訊品質能夠快速的從不好的環境中恢復，有了這些機制我們就能夠確保每個使用者視訊的延時在我們所指定的值之下，持續的提供有如同主從式架構中良好的服務品質，以達到視訊會議系統所需之低延遲性的要求。
同時我們也設計了各種的實驗來測試我們的系統，包含節點加入、退出、偵測法則和救援機制，並且收集其數據做統計和分析，根據些數據分析的結果來驗證我們的系統的可行性。

關鍵字

點對點 ； 串流 ； 網狀拓樸 ； 樹狀拓樸 ； 低延遲 ； 現場轉播

並列摘要

Abstract
Peer-to-Peer (P2P) network applications have become increasingly widespread in today’s Internet. The primary reason for the emergence of P2P network has been the ability to reduce server burdens and bandwidth costs. However, these benefits do not automatically guarantee a reduction in, and/or control of, transmission delays. When streaming live broadcasts, transmission delays are an important factor directly affecting the quality of user experience. Generally speaking, in a large-scale live broadcast using P2P technology, minimizing transmission delays is not crucial as long as the latency is consistent and stable; however, for an online video conferencing system, transmission delays must be strictly controlled so as to be no more than a few seconds, in order to ensure the interactivity among the conference participants.
This paper proposes a P2P system using a hybrid mesh topology. We call this system “Low-Latency Peer-to-Peer Network” (LLP2P). One of the key features of this system is the ability to minimize server output bandwidth at any specified length of latency. In addition, this system also provides a series of detection and rescue algorithms as mechanisms that allow users to quickly recover from poor streaming performance caused by unstable network quality for their parent nodes. With these mechanisms, we can ensure that the streaming latency for every user is below our specified value, so as to provide the same quality service, in a sustainable manner, as would be offered by the client-server architecture.
We have also designed various experiments to test our system, including joining and leaving nodes, detection algorithm, and rescue mechanism. Data from these experiments have been collected and statistically analyzed, in order to verify the feasibility of our system accordingly.

並列關鍵字

p2p ； streaming ； mesh topology ； tree topology ； low latency ； live broadcast

參考文獻

[7] Magharei, N., Rejaie, R., & Member, S. (2009). “PRIME : Peer-to-Peer Receiver-Driven Mesh-Based Streaming”, 17(4), 1052–1065.

[8] Russo A and Lo Cigno R, “Delay-Aware Push/Pull Protocols For Live Video Streaming in P2P Sytem”, 2010 IEEE International Conference on Communications (ICC), May 2010.

[9] N. Magharei and R. Rejaie, “Understanding Mesh-based Peer-to-Peer Streaming”, NOSSDAV 2006, May 2006.

[10] Magharei, N., Rejaie, R., & Guo, Y. (2007). “Mesh or Multiple-Tree: A Comparative Study of Live P2P Streaming Approaches. “IEEE INFOCOM 2007 - 26th IEEE International Conference on Computer Communications, 1424–1432. doi:10.1109/INFCOM.2007.168

[11] D.A. Tran, K.A. Hua, and T. Do, “ZIGZAG: An Efficient Peer-to- Peer Scheme for Media Streaming,” Proc. IEEE INFOCOM, vol. 2, pp. 1283-1292, Mar. 2003.