隨著網路使用者網路頻寬的大增，利用點對點傳輸技術達到即時影像串流已經是一個可行的技術。然而，目前對於點對點即時影像傳輸延遲的研究，依然不多見。本篇論文提出了一個點對點的網路拓樸結構建構法，使得使用者收到即時影像的延遲可以減小。本方法利用減少使用者與視訊伺服器之間的hop數為出發點，並以網路使用者網路頻寬分佈為基礎，建構出一個預測理想模型。接著使用者的加入離開與系統的拓樸，皆依照預測的模型來建構。實驗結果顯示，本篇論文所提出的方法成功的減少使用者與視訊伺服器之間的hop數，並且減少實際傳輸延遲。除此之外，利用本方法也可以有效減少傳輸時的封包遺失率。

Due to the fast growing bandwidth of Internet users, the P2P video streaming on the Internet becomes one of impaortant solutions to release the traffic load. However, the current studies fall short of addressing the video delay issue on live P2P streaming. In this research, we proposed a topology construction method: Smart-Fit, towards minimizing the transmission delay between users and video server. The concept is based on minimizing the hop counts between server and users, in further to reduce the delay. With the bandwidth variety of Internet users, the proppsed method builds a predicted ideal template. Then the users’ joining and leaving behaviors and the system’s topology are constructed according to the template. Simulation results show the proposed method successfully reduces the hop count and the transmission delay between users and server. Moreover, due to the reduction of hop count, the packet loss rate is also reduced.

1. Introduction 1
1.1 Problem Statement 2
2. Related Work 3
3. Preliminaries and Definitions 4
3.1 Network Delay 4
3.1.1 Effects of Delay 5
3.2 The Definition of Average Hop Count 7
3.3 The Preliminaries 6
4. The Proposed Method 8
4.1 Strategy: Random 8
4.2 Strategy: Best-Place First 9
4.2.1 Local Optimum of Best-Place First 11
4.3 The Framework of the Minimum Hop Count Topology 14
4.4 The Placement Dilemma 14
4.5 The Smart-Fit Strategy 16
4.5.1 Building Template 16
4.5.2 Arrival of Peers 18
4.5.3 Deviations 19
4.5.4 Departure of Peers 20
4.5.5 The Smart-Fit Algorithm 22
5. Experimental Results 25
5.1 Average Hop Count 26
5.2 Average Packet Delay 28
5.3 Packet Loss Rate 30
5.4 Server Bandwidth Utilization 33
5.5 The Control Overhead 33
5.6 The Parent Waiting Time of Smart-Fit 34
5.7 The effect of predicting period T in Smart-Fit 35
6. Conclusions 37
References 38

[1] S. Saroiu, P. K. Gummadi, and S. D. Gribble, “A Measurement Study of Peer-to-Peer File Sharing Systems,” in Proceedings of the Multimedia Computing and Networking 2002, pp.156-170.
[2] X. Zhang, J. Liu, B. Li, and T. P. Yum, “CoolStreaming/DONet: A DataDriven Overlay Network for Efficient Live Media Streaming,” in Proceedings of the IEEE INFOCOM’ 05 Conference, Mar. 2005, pp.2102-2111.
[3] M. Zhang, L. Zhao, J. L. Y. Tang, and S. Yang, “GridMedia: A Multi-Sender Based Peer-to-Peer Multicast System for video streaming ” in Proceedings of the IEEE International Conference on Multimedia and Expo, Jul. 2005, pp.614-617.
[4] V. Venkatramen, K. Yoshida, and P. Francis, “Chunkyspread: Heterogeneous Unstructured Tree-Based Peer-to-Peer Multicast,” in Proceedings of the IEEE 14th International Conference on Network Protocols, Nov. 2006, pp.2-11.
[5] T. Small, B. Li, and B. Liang, “Outreach: Peer-to-Peer Topology Construction towards Minimized Server Bandwidth Costs,” IEEE Journal on Selected Areas in Communication, VOL. 25, No. 1, Jan. 2007, pp.35-45.
[6] J. Jannotti, D. K. Gifford, K. L. Johnson, M. F. Kaashoek, J. W. O'Toole, Jr., “Overcast: Reliable Multicasting with an Overlay Network,” in Proceedings of USENIX Symposium on Operating System Design and Implementation, Oct. 2000, pp. 197-212.
[7] M. Castro, P. Druschel, A. -M. Kermarrec, A. Rowstron, and A. Singh, “SplitStream: High-bandwidth Content Distribution in Cooperative Environments,” in Proceedings of the 2nd International Workshop on Peer-to-Peer Systems, VOL. 2735, Feb. 2003, pp. 292-303.
[8] V. padmanabhan, H. Wang, P. Chou, and K. Sprianifkulchai, “Distributing Streaming Media Content using Cooperative Networking,” in Proceedings of the 12th International Workshop on Network and Operating Systems Support for Digital Audio and Video, May. 2002, pp. 177-186.
[9] S. Banerjee, B. Bhattacharjee, and C. Kommareddy, “Scalable Application Layer Multicast,” in Proceedings of the ACM SIGCOOM’02, VOL. 31, Aug. 2002, pp.205-217.
[10] D. Tran, K. Hua, and T. Do, “A Peer-to-Peer Architecture for Media Streaming,” IEEE Journal on Selected Ares in Communications, VOL. 22, Jan. 2004, pp. 121-133.
[11] P. J. Wu, H. H. Kao, C. N. Lee and J. N. Hwang, “Overcoming Burst Packet Loss in Peer-to-Peer Live Streaming System,” in Proceedings of the IEEE International Symposium on Circuits and Systems, May. 2008, pp.3514-3517.
[12] B. Choen, “Incentives Build Robustness in BitTorrent,” in Proceedings of the 1st Workshop on Economics of Peer-to-Peer Systems. Berkeley, CA, USA, Jun. 2003.
[13] AT&T Global IP Network Home, http://ipnetwork.bgtmo.ip.att.net/pws/index.html
[14] NTT Communications Global IP Network SLA, http://us.ntt.net/support/sla/network/
[15] Telchemy, Incorparated, “Impact of Delay in Voice over IP Services,” Telchemy Application Notes, Series VoIP Performance Management, Jan. 2006, pp. 1-7.
[16] V. Vishnumurthy and P. Francis, “On Heterogeneous Overlay Construction and Random Node Selection in Unstructured P2P Networks,” in Proceedings of the IEEE INFOCOM ’06 Conference, Apr. 2006, pp. 1-12.
[17] S. Banerjee, B. Bhattacharjee, and S. Parthasarathy, “A Protocol for Scalable Application Layer Multicast,” in Proceedings of the ACM SIGCOMM’02, VOL. 31, Aug. 2002, pp. 205-217.
[18] Y. Liu, L. Xiao, and L. M. Ni, “Building a Scalable Bipartite P2P Overlay Network,” IEEE Transaction on Parallel and Distributed Systems, VOL. 18, NO. 9, Sep. 2007, pp. 1296-1306.
[19] M. El-Kadi, S. Olariu, and H. Abdel-Wahab, “A Rate-Based Borrowing Scheme for QoS Provisioning in Multimedia Wireless Network,” IEEE Transaction on Parallel and Distributed Systems, VOL. 13, NO. 2, Feb. 2002, pp. 156-166.
[20] A. Malla, M. El-Kadi, S. Olariu, and P. Todorova, “A Fair Resource Allocation Protocol for Multimedia Wireless Networks,” IEEE Transaction on Parallel and Distributed Systems, VOL. 14, NO. 1, Jan. 2003, pp. 63-71.