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Bandwidth Control in Multiple Video Windows’ Conferencing System

Bandwidth Control in Multiple Video Windows’ Conferencing System. Fukuoka , Japan 23 January 2003. Present by : Lee Hooi Sien. Benefits. Communicate with multiple parties at the same time Improve Productivity Allow boardroom conferencing. Network Protocol. Drawbacks.

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Bandwidth Control in Multiple Video Windows’ Conferencing System

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  1. Bandwidth Control in Multiple Video Windows’ Conferencing System Fukuoka , Japan 23 January 2003 Present by : Lee Hooi Sien

  2. Benefits • Communicate with multiple parties at the same time • Improve Productivity • Allow boardroom conferencing

  3. Network Protocol

  4. Drawbacks • Control Complexity Increase • Bandwidth problem • Congestion occurs • Packet loss • Severe drop in video quality.

  5. Solving Methods • Multicast • Rate Control • Preemptive Bandwidth Allocation

  6. Multicast • Assign group IP addresses to groups of users • Information just need to be sent once to the group IP address • Uses network resources and bandwidth more efficiently

  7. Rate Control • Two Main functions • Estimate the available bandwidth • Match video rate to available bandwidth • Can be performed at : • Sender • Receiver

  8. Rate Control - Source • Source explicitly adapts the video rate. • Feedback from the receiver is used to estimate the available bandwidth – Packet loss rate. • Methods for estimating bandwidth • Probe-based method

  9. Rate Control - Receiver • Selects the video rate from a number of possible rates. • Method used : Receiver Driven Layered Multicast • Sender codes video with scalable or layered coder • Sends different layers over different multicast groups • Receives an appropriate number of layers up to its available bandwidth.

  10. Rate Control - Receiver • Need modification – Not suitable for multiple data streams transmission. • Proposed method – Based on Receiver-based Layered Multicast (RLM) • Utilize priority information on the video quality • Specify which video stream should be received with high quality • Others received with the lowest quality • Only allow adjustment for high priority video stream

  11. Preemptive Bandwidth Allocation • Flexibly decreased or increased according to the congestion of networks. • Main function – preempt bandwidth • Condition – Shared-based multicast tree • Involve 2 admission controls

  12. Admission Control • First Admission Control • Check available bandwidth • Satisfied?? • If not, proceed to second admission control • Second Admission Control • Check if any possible bandwidth preemption • If succeed, calculate amount of preemptable bandwidth has to release

  13. Conclusion • Bandwidth control is important in conferencing system because :- • Video packets require higher bandwidth • Multiple video stream • Complexity in controlling the streams

  14. Thank You

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