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IP TV Bandwidth Demand: Multicast and Channel Surfing

IP TV Bandwidth Demand: Multicast and Channel Surfing. INFOCOM, 2007 Chen Bin Kuo (20077202) Young J. Won (20063292). DPNM Lab. Outline. Introduction Problem Description and Assumptions Mathematical Model Simulation Result Conclusions Discussion. Introduction.

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IP TV Bandwidth Demand: Multicast and Channel Surfing

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  1. IP TV Bandwidth Demand: Multicast and Channel Surfing INFOCOM, 2007 Chen Bin Kuo (20077202) Young J. Won (20063292) DPNM Lab.

  2. Outline • Introduction • Problem Description and Assumptions • Mathematical Model • Simulation Result • Conclusions • Discussion

  3. Introduction • Fiber optic access networks (fiber-to-the-premises and fiber-to-the-node) have boosted individual user’s broadband access speeds. • IP networks may soon become a delivery mechanism for broadcast television content.

  4. Introduction (contd.) • IP data packets in FTTP network might include: • Broadcast video • Video-on-demand (VOD) • Web applications such as web surfing, online gaming, and p2p file transfers • Demand of a video stream (under MPEG-2 encoding) • Standard definition (SD) : 3.75 Mbps • High definition (HD) : 15 Mbps • Evaluating bandwidth demand is necessary.

  5. Introduction (contd.) Core router and edge router deliver content to the edge of the network . Portion of a FTTP network Core Router Edge Router An OTL forwards the content over a PON to an ONT at each subscriber’s premise. How big do these links need to be? 2000 subscribers Optical Line Terminal (OLT) Passive Optical Network (PON) 32 subscribers Optical Network Terminal (ONT)

  6. Problem Description • Steady state demand • Analytical methods for engineering links often assume stationary (steady state) busy hour traffic. • All viewers have settled into channels • Using multicast to satisfy demand • Channel surfing • Disrupting the steady state at every commercial break • Significant additional bandwidth demand is required.

  7. Multicast in Steady State Edge Router 6 video stream required 5 video stream required The network needs to deliver only one video stream for the same channel to the OLT where it must divide the stream for two viewers. OTL If there exist two viewers watch the same channel (5 different in total) If all viewers watch different channels (6 different channels) Viewers

  8. Problem Description (contd.) • The way to make channel changes fast is to send surfers unicast (one per viewer)streams at higher rates. Channel change server Playout buffer (in the set top box) Usual rate Higher rate

  9. Channel Surfing of One Viewer Settled in one channel (steady state) Channel surfing (commercial break) Bandwidth • Bandwidth planning issue • What is the demand? • How to model the traffic? Time

  10. Problem Assumptions • A viewer: a device capable of receiving an IPTV stream • Each set top box always remains on and receives some video stream • This paper only to characterize broadcast IP TV’s contribution (from edge router to an OLT) • Homogeneous viewers

  11. Problem Assumptions(contd.) • The program definition is independent of the renewal process • The number of active viewers is constant during commercial break • Commercial breaks on all channels begin at the same time and all active viewers begin surfing at the same time

  12. Mathematical Model Channel Surfing Model – Single User Steady State Multicast Model The Time to Fill the Playout Buffer Single Viewer Behavior Focusing on the viewers who are not surfing Extend to multiple users Bandwidth Demand Combined Model (Multiple Users)

  13. Multicast Model Channel i, probability that a viewer will choose

  14. Channel Surfing Model Single Viewer

  15. Channel Surfing Model Single Viewer (contd.) The time the bandwidth must stay high after a single channel change A random variable, which is the bandwidth demand of a viewer at time t

  16. Combined Model – Multiple Viewers

  17. Experimental Parameters

  18. Simulation Result The channel surfing ends The time to start channel surfing when commercial break starts

  19. Conslusions • The paper developed a model to quantify bandwidth demand during the transition from surfing to steady state viewing. • The example with 400 viewers shows mean demand during surfing peaking at almost two times the steady state level if the service provider offers fast IP TV channel changes.

  20. Discussion • Assumptions of the mathematical model • How to model the user behavior more realistic? • What else can we contribute to the IP TV filed?

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