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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
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
Six-channel cluster and its sub-cluster in FPB
5-channel cluster
4-channel cluster
T P
Wanted segments
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
Six-channel cluster and its sub-cluster in FPB
5-channel cluster
4-channel cluster
T P
Wanted segments
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
Six-channel cluster and its sub-cluster in FPB
4-channel cluster
3-channel cluster
T P
Wanted segments
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
Six-channel cluster and its sub-cluster in FPB
4-channel cluster
3-channel cluster
T P
Wanted segments
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
Six-channel cluster and its sub-cluster in FPB
3-channel cluster
2-channel cluster
T P
Wanted segments
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
Six-channel cluster and its sub-cluster in FPB
3-channel cluster
2-channel cluster
T P
Wanted segments
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
Six-channel cluster and its sub-cluster in FPB
T,P
Wanted segments
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
Six-channel cluster and its sub-cluster in FPB
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’ }
Smooth Transition PropertySmooth Transition Property
Smooth Transition PropertySmooth Transition Property
Performance EvaluationPerformance Evaluation
Comparison of PB scheme (requiring clients listen to two channels)
Performance EvaluationPerformance Evaluation
Efficiency of Parsimonious FPB
Performance EvaluationPerformance Evaluation
Performance of the smooth workload adaptive scheme
single video case
Performance EvaluationPerformance Evaluation
Performance of the smooth workload adaptive scheme
single video case
Performance EvaluationPerformance Evaluation
Performance of the smooth workload adaptive scheme
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
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