1. Smooth Workload Adaptive Broadcast Yang Guo, Lixin Gao Don Towsley, Subhabrata Sen IEEE TRANSACTIONS ON MULTIMEDIA, APRIL 2004

2. Outline Introduction Workload adaptive broadcast architecture Flexible Periodic Broadcast Smooth Transition Property Performance Evaluation Conclusion

3. Introduction Develop bandwidth-efficient techniques for –Delivering popular video –To a large, asynchronous client population –With time-varying demand characteristics In the past, PB (Periodic Broadcast) scheme was used

4. Drawbacks of PB scheme Workload insensitivity –Not adapt to changing workload demands Delayed playback –Clients experience a playback delay

5. What desirable in this scheme ? Parsimonious transmission –Transmits a segment only if required Workload adaption –Dynamically adjusts the number of channels Instantaneous playback –Enables instantaneous or near-instantaneous playback

6. Related Work Compare to “Data broadcasting and seamless channel transition for highly- demanded video” –Advantage: smooth channel transition property –Disadvantage: It require the client to listen to all channels simultaneously Without using parsimonious transmission, so become inefficient when a video turn to unpopular

7. Workload adaptive broadcast architecture 1 2 request ClientServer 2 1 unicast multicast 1.Modified PB scheduler 2. Workload adaptor

8. Modified PB Scheduler BBBBBBBB B BBB 232323232323 111111111111 (multicast) Instantaneous playback (unicast) 678967896789 454545454545 AA Client 1Client 2 Parsimonious PB (multicast) Near-Instaneous playback (multicast)

9. Workload Adaptor Determine optimal channel number depend on the arrival rate and video length

10. Workload Adaptor – : the arrival rate after the n-th update period – : the number of arrivals during n-th period – : the weight – : the period length W, the average arrival rate converges to the current arrival rated more quickly

11. Flexible Periodic Broadcast Fn : Channel n is responsible for delivering Fn consecutive segments to clients

12. Server Transmission schedule Suppose FPB use K channels to transmit a video clip of length L Start rule : n-th channel start transmission after (n-1)-th channel complete the transmission of segments Repeat Rule : Each channel repeat its transmission schedule once every segments

13. Server Transmission Schedule Transmission schedule within a period: –For channel n, n=2,3,…,K-1, the transmission schedule comprises K-n+1 batches of segments –The first batch consists of segments Ex. K=6, n=3, -> [3+1,6] -> (4,5,6) –The second batch, the same as the leading segments in the first batch -> (4,5) –Batch i,,consist of segments contained in the previous i-2 batches, from batch 1 to batch i-2 -> (4,5,6) (4,5,6,4,5) 1 2 3 5 8 13

14. Server Transmission Schedule 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB 5-channel cluster 6-channel cluster

15. Client Reception Schedule

16. 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB 5-channel cluster 4-channel cluster TP Wanted segments

17. Client Reception Schedule 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB 5-channel cluster 4-channel cluster TP Wanted segments

18. Client Reception Schedule 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB 4-channel cluster 3-channel cluster TP Wanted segments

19. Client Reception Schedule 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB 4-channel cluster 3-channel cluster TP Wanted segments

20. Client Reception Schedule 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB 3-channel cluster 2-channel cluster TP Wanted segments

21. Client Reception Schedule 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB 3-channel cluster 2-channel cluster TP Wanted segments

22. Client Reception Schedule 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB T,P Wanted segments

23. Client Reception Schedule 4564545645645 2020 21212 2323 2424 2525 2626 2727 2828 2929 3030 3131 3232 78910101 78978910101 1,2,3,5,8,13 1212 1313 1414 1515 1616 1717 1818 1919 1212 1313 1414 1515 1616 2322323223223 1111111111111 Channel 3 Channel 1 Channel 4 Channel 5 Channel 6 Channel 2 Six-channel cluster and its sub-cluster in FPB T,P Wanted segments

24. Smooth Transition Property The clients already starting their service not experience any disruption during the transition The newly arrived clients make use of the FPB scheme with K’ channels The total number of channels used during the transition period is no larger than max{ K, K’ }

25. Smooth Transition Property

27. Performance Evaluation Comparison of PB scheme (requiring clients listen to two channels)

28. Performance Evaluation Efficiency of Parsimonious FPB

29. Performance Evaluation Performance of the smooth workload adaptive scheme single video case

30. Performance Evaluation Performance of the smooth workload adaptive scheme single video case

31. Performance Evaluation Performance of the smooth workload adaptive scheme multiple video case

32. Conclusion Present –a workload adaptive broadcast architecture and –smooth workload broadcast based on FPB –To provide VoD service to a large, asynchronous client population with time- varying workload