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

Smooth Workload Smooth Workload Adaptive BroadcastAdaptive Broadcast

Yang Guo, Lixin GaoYang Guo, Lixin Gao

Don Towsley, Subhabrata SenDon Towsley, Subhabrata SenIEEE TRANSACTIONS ON MULTIMEDIA , APRIL 2004IEEE TRANSACTIONS ON MULTIMEDIA , APRIL 2004

OutlineOutline

• Introduction

• Workload adaptive broadcast architecture

• Flexible Periodic Broadcast

• Smooth Transition Property

• Performance Evaluation

• Conclusion

IntroductionIntroduction

• 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

Drawbacks of PB schemeDrawbacks of PB scheme

• Workload insensitivity– Not adapt to changing workload demands

• Delayed playback– Clients experience a playback delay

What desirable in this scheme ?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

Related WorkRelated 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

Workload adaptive broadcast Workload adaptive broadcast architecturearchitecture

1

2request

Client Server

2

1

unicast

multicast

1. Modified PB

scheduler

2. Workload adaptor

Modified PB SchedulerModified PB Scheduler

B B B B B B B B B B B B

2 3 2 3 2 3 2 3 2 3 2 3

1 1 1 1 1 1 1 1 1 1 1 1

(multicast)

Instantaneous playback (unicast)

6 7 8 9 6 7 8 9 6 7 8 9

4 5 4 5 4 5 4 5 4 5 4 5

A A

Client 1 Client 2

Parsimonious

PB

(multicast)

Near-Instaneous playback (multicast)

Workload AdaptorWorkload Adaptor

• Determine optimal channel number depend on the arrival rate and video length

Workload AdaptorWorkload Adaptor

• – : the arrival rate after the n-th update period

– : the number of arrivals during n-th period

– : the weight

– : the period length

/)1(1 nnn

Awwn

nAw

W , the average arrival rate converges to the current arrival rated

more quickly

Flexible Periodic BroadcastFlexible Periodic Broadcast

• Fn : Channel n is responsible for delivering Fn consecutive segments to clients

Server Transmission scheduleServer 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

1nF

KF

Server Transmission ScheduleServer 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)

1nF

1 2 3 5 8 13

Server Transmission ScheduleServer Transmission Schedule

4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

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

Client Reception ScheduleClient Reception Schedule


4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

Channel 3

Channel 1

Channel 4

Channel 5

Channel 6

Channel 2


5-channel cluster

4-channel cluster

T P

Wanted segments


4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

Channel 3

Channel 1

Channel 4

Channel 5

Channel 6

Channel 2


5-channel cluster

4-channel cluster

T P

Wanted segments


4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

Channel 3

Channel 1

Channel 4

Channel 5

Channel 6

Channel 2


4-channel cluster

3-channel cluster

T P

Wanted segments


4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

Channel 3

Channel 1

Channel 4

Channel 5

Channel 6

Channel 2


4-channel cluster

3-channel cluster

T P

Wanted segments


4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

Channel 3

Channel 1

Channel 4

Channel 5

Channel 6

Channel 2


3-channel cluster

2-channel cluster

T P

Wanted segments


4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

Channel 3

Channel 1

Channel 4

Channel 5

Channel 6

Channel 2


3-channel cluster

2-channel cluster

T P

Wanted segments


4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

Channel 3

Channel 1

Channel 4

Channel 5

Channel 6

Channel 2


T,P

Wanted segments


4 5 6 4 5 4 5 6 4 5 6 4 5

20

21

22

23

24

25

26

27

28

29

30

31

32

7 8 9 10

11

7 8 9 7 8 9 10

11

1,2,3,5,8,13

12

13

14

15

16

17

18

19

12

13

14

15

16

2 3 2 2 3 2 3 2 2 3 2 2 3

1 1 1 1 1 1 1 1 1 1 1 1 1

Channel 3

Channel 1

Channel 4

Channel 5

Channel 6

Channel 2


T,P

Wanted segments

Smooth Transition PropertySmooth 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’ }



Performance EvaluationPerformance Evaluation

Comparison of PB scheme (requiring clients listen to two channels)


Efficiency of Parsimonious FPB


Performance of the smooth workload adaptive scheme

single video case



single video case



multiple video case

ConclusionConclusion

• Present – a workload adaptive broadcast architecture an

d – smooth workload broadcast based on FPB– To provide VoD service to a large, asynchron

ous client population with time-varying workload

Documents

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