CStream: Neighborhood Bandwidth
Aggregation For Better Video Streaming
Thangam Vedagiri Seenivasan
Advisor: Mark Claypool
Reader: Robert Kinicki
M.S. Thesis Presentation
1
Motivation
• Increasing popularity of video streaming[Cisco survey 09’]
Video traffic
Video traffic
25%
2009
[Internet traffic]
Other traffic
Other traffic
75%
• High definition videos
50% 50%
2012
[Internet traffic]
Encoding rate: 8 Mbps to 20 Mbps
• Clients still have limited Internet bandwidth
Dialup, DSL
3G
128 Kbps to 3 Mbps
384 Kbps to 2 Mbps
Video streaming still a challenge
2
Motivation
High density of Internet connections
even in this room!!
Idle users = spare bandwidth
Potential unused bandwidth most of the time
3
Motivation
• Devices have multiple network interfaces
Can form ad-hoc networks
Device can connect to nearby nodes
at the same time it is connected to Internet
4
CStream – Collaborative Streaming
Aggregates bandwidth from multiple clients in a neighborhood
for video streaming
Frame 2
Internet
CStream Video
Server
Frame 3
Frame 1
CStream Video Player
5
Related Work
• Download Accelerators [Rodriguez et al. 00’]
– Multiple connections to mirrored servers
• Multi-homing [Chebrolu et al. 06’]
– Multi-homed devices, with multiple interfaces
– Aggregate bandwidth from multiple interfaces
• COMBINE [Ananthanarayanan et al. 07’]
– Aggregate bandwidth in phones for HTTP
download of large files
• Link Alike [Jakubczak et al. 08’]
– Improve client upload capacity for file transfer
6
Outline
•
•
•
•
•
•
•
Motivation
Challenges
Design
Implementation
Evaluation
Future Work
Conclusion
7
Challenges
• Neighbor discovery and maintenance
– Find and connect to neighbors
– Updated knowledge of neighbor status
• Multi-path streaming
– Stream through multiple nodes
– Frame distribution across links
– Effectively utilize available bandwidth
8
Challenges
• Handle dynamically changing neighborhood
– Adapt to neighbors joining and leaving
– Use the bandwidth of new neighbors joining
– Tolerant to neighbors leaving abruptly
• Buffering and Playing
– Buffering mechanism
– Discard late frames (I-policy) or Wait for late
frames (E-policy)
9
Outline
•
•
•
•
•
•
•
Motivation
Challenges
Design
Implementation
Evaluation
Future Work
Conclusion
10
Design
Video
Server
Video
Database
Plan Handler
Video
query
Request
Plan
Plan
Video
Frame Distributor
Frames
Frames
Neighbor
Meta data
Video
Player
Buffer
Manager
Proxy
Video Plan
Manager
Frames
Helper Manager
Update
Frames
Neighbor Manager
I-CAN-HELP
Client
Wireless ad-hoc network
11
Client
• Neighbor manager
Video
Player
Buffer
Manager
Video Plan
Manager
Frames
Update
Neighbor Manager
– Keeps updated knowledge of active neighbors
– Informs the Video Plan Manager about change in
neighborhood
– Receives frames from the neighbor and forwards
to the Buffer Manager
• Video Plan Manager
– Informs the server about the active neighbors (IP
Address, Port to stream) - streaming plan
– Dynamically updates streaming plan based on
input from Neighbor Manager
12
Client
• Buffer Manager
Video
Player
Buffer
Manager
Video Plan
Manager
Frames
Update
Neighbor Manager
– Receives frames from the server
– Receives frames from the neighbor through the
Neighbor Manager
– Maintains playout buffer
• Video Player
– Extracts frames from the Buffer Manager and
plays it
– Implements E-policy (wait for late frames)
13
Design
Video
Server
Video
Database
Plan Handler
Video
query
Video
Player
Plan
Plan
Buffer
Manager
Video
Frame Distributor
Frames
Frames
Proxy
Video Plan
Manager
Frames
Neighbor
Helper Manager
Update
Frames
Neighbor Manager
I-CAN-HELP
Client
Wireless ad-hoc network
14
Neighbor
Proxy
Helper Manager
• Proxy
– Receives frames from the server
– Sends to the client
• Helper Manager
– Sends periodic I-CAN-HELP messages that it is
willing to collaborate
– Stops when there is user and network activity
15
Design
Video
Server
Video
Database
Plan Handler
Video
query
Video
Player
Plan
Plan
Buffer
Manager
Video
Frame Distributor
Frames
Frames
Proxy
Video Plan
Manager
Frames
Neighbor
Helper Manager
Update
Frames
Neighbor Manager
I-CAN-HELP
Client
Wireless ad-hoc network
16
Video
Database
Video Server
• Frame Distributor
Plan Handler
Plan
Video
Frame Distributor
– Runs a frame assignment module
– Sends assigned frames to client and neighbors
– Assignment adapts to the bandwidth of each
client
• Plan Handler
– Receives dynamic plan about active neighbors
from the client
– Updates the Frame Distributor to adapt streaming
to the changing neighborhood
17
Outline
•
•
•
•
•
•
•
Motivation
Challenges
Design
Implementation
Evaluation
Future Work
Conclusion
18
Implementation
• Neighbor Management
• Frame Distribution
• Adapting to changing neighborhood
– Neighbor joining
– Neighbor leaving
• Buffering and Playing
19
Neighbor Management
Video Server
Frames
I-CAN-HELP
Frames
Plan
Frames
I-CAN-HELP
REQUEST
SSID: CStream
Ad-hoc network
Ad-hoc network
Client
20
Frame Distribution
Frames
1
2
3
4
5
6
7
8
9
10 11 12 13 14
Neighbors N1 and N2
Thread - N1
Thread - C
Thread - N2
1
6
2
5
4
3
TCP
1
1
6
2
4
5
1
3
2
4
5
21
Neighbor Joining
22
Neighbor Joining
Frames
7
8
9
10 11 12 13 14
New neighbor N3
Thread - N1
Thread - C
Thread - N2
Thread – N3
7
TCP
1
6
2
4
5
1
3
7
2
4
5
23
Neighbor Leaving
24
Neighbor Leaving
Frames
6
8
9
10 11 12 13 14
Neighbor N1 left
Last Frame Received - 1
Thread - N1
Thread - C
Thread - N2
Thread – N3
CStream is fault-tolerant
6
TCP
6
5
6
1
3
7
2
4
5
25
Buffering Policy (E-policy)
• Initial Buffering before first frame played
– Playout buffer: n seconds (2 sec in our
implementation)
– Wait till (n * encodedFrameRate) frames buffered
• Stop and Rebuffering
– frame to be played, not arrived
• Resume video after rebuffering
– 2 seconds of frames from the current frame to be
played received
26
Outline
•
•
•
•
•
•
•
Motivation
Challenges
Design
Implementation
Evaluation
Future Work
Conclusion
27
CStream
• Built the complete system
– Video Server, Neighbor, Client Video Player
• C# .NET
– 3000 lines of code
• AVI Video Library [C. John, CodeProject]
– Extract frame by frame from avi files
28
Experimental Setup
SERVER
Netem, CBQ
WPI LAN
BRIDGE
Ethernet
Ad-hoc network
NEIGHBOR
Ad-hoc network
CLIENT
NEIGHBOR29
Experiment Parameters
• Bandwidth from the video server
– Class based queuing discipline, Netem
– 250 Kbps, 500 Kbps, 1 Mbps, 2 Mbps, 3 Mbps, 5 Mbps
– Equal bandwidth, Unequal bandwidth for nodes
• Number of neighbor nodes
– 0, 1, 2
• Location of neighbor nodes
– Signal Strength: Excellent, Good, Weak
• Video Content
– Short Video
– Long Video
30
Video Content
Short Video
cartoon_dog.avi
Long Video
foreman.avi
Length
8 seconds
33 seconds
Size
10 MB
26 MB
Encoded bitrate
10Mbps
6.3Mbps
Frames per second
15
12
Average Frame Size
85 KB
68 KB
Total Frames
120
400
Resolution
320×240
176×144
31
Performance Metrics
• Aggregate Throughput (Kbps)
– Application throughput at the client node
• Playout Time
– Total time to play the entire video
• Startup Delay
– Time taken to play the first frame
• Rebuffer Events
– Number of stop and buffer events
• Frame Distribution
– Contribution of each node vs. ratio of bandwidth
32
Throughput (Short Video)
11047
11000
10000
Per Host
Capacity
Constraint
9000
7396
Throughput (Kbps)
8000
7096
7000
Almost 2x improvement with 1 neighbor
5411
Almost 3x improvement
with 2 neighbors
5047
5000
6000
3754
3472
3000
2806
2576
1767
1000
938
477
239
0
0
500 Kbps
1 Mbps
2 Mbps
4000
2000
250 Kbps
1854
3 Mbps
5 Mbps
1430
962
486
1
Number of Neighbors
Client and Neighbors have same bandwidth
Neighbors had excellent signal strength to the client
734
2
33
Throughput (Long Video)
10925
Throughput (Kbps)
10000
8000
7437
7624
Per Host
Capacity
Constraint
250 Kbps
6000
5338
1 Mbps
5045
3902
4000
2 Mbps
3558
2778
2611
2000
1777
932
476
0
500 Kbps
3 Mbps
5 Mbps
1854
1434
955
483
726
238
0
1
Number of Neighbors
Client and Neighbors have same bandwidth
Neighbors had excellent signal strength to the client
2
34
Playout Time
900
898.88
800
Playout time (s)
700
600
250 Kbps
500
448.28
500 Kbps
442.59
1 Mbps
400
294.7
300
230.2
3 Mbps
224.75
5 Mbps
200
150.08
121.36
100
2 Mbps
83.44
56.04
0
0
116.6
61.13
43.44
35.32
1
Number of Neighbors
77.42
40.56
34.85 35.57
2
35
Startup Delay
52.97
50
Startup Delay (s)
40
250 Kbps
30
500 Kbps
26.4
26.69
1 Mbps
20
13.94
10
3 Mbps
13.68
5 Mbps
9.57
7.58
6.33
0
2 Mbps
17.9
3.65
0
7.32
4
2.94
2.12
1
Number of Neighbors
5.12
2.95
2.37
1.65
2
36
Rebuffer Events
Maximum Rebuffer Events - 15
Neighbors
Bandwidth
0
1
2
250 Kbps
15
14.3
14
500 Kbps
15
13
12
1 Mbps
13
11
9
2 Mbps
11
6.6
2
3 Mbps
9
2.6
0
5 Mbps
6
0
0
Need three 3 Mbps links or two 5Mbps links
to stream without rebuffering
37
Frame Distribution
Expected Actual
Expected
Actual
Client – 2 Mbps
Neighbor– 2 Mbps
Client– 2 Mbps
Neighbor– 1 Mbps
Expected
Actual
Client– 2 Mbps
Neighbor1 – 2 Mbps
Neighbor2– 2 Mbps
Expected
Actual
Client – 3 Mbps
Neighbor1– 2 Mbps
Neighbor2 – 1 Mbps
38
Short Video – 0 Neighbors
Experiment
Client – 2 Mbps
39
Short Video – 1 Neighbor
Experiment
Client – 2 Mbps
Neighbor1 – 2 Mbps
40
Short Video – 2 Neighbors
Experiment
Client – 2 Mbps
Neighbor1 – 2 Mbps
Neighbor2 – 2Mbps
41
Neighbors Joining
7000
5747 kbps
Throughput (last 20 frames)
Kbps
6000
5000
1st Neighbor joined
4000
3576 kbps
3000
1787 kbps
2000
2nd Neighbor joined
1000
0
0
10
20
30
40
50
60
70
80
Time (s)
Experiment: Long Video, Client – 2 Mbps, Neighbor1 – 2 Mbps, Neighbor2 – 2 Mbps
42
Neighbor Leaving
Throughput (last 20 frames)
Kbps
7000
1st Neighbor left
5653 kbps
6000
2nd Neighbor left
5000
3773 kbps
4000
3000
1781kbps
2000
1000
0
0
10
20
30
40
Time (s)
50
60
70
Experiment: Long Video, Client – 2 Mbps, Neighbor1 – 2 Mbps, Neighbor2 – 2 Mbps
43
Neighbor Joining and Leaving
Experiment
Client – 3 Mbps
Neighbor1 – 3 Mbps
44
Impact of Wireless
Aggregate Throughput (Kbps)
3500
Experiment
Client – 2 Mbps
Neighbor1 – 2 Mbps
3509
3000
2395
2500
1977
2000
1500
1000
500
0
Excellent
Iperf – 13 Mbps
Good
Iperf – 980 Kbps
Poor
Iperf – 520 Kbps
Wireless Signal Strength
Bandwidth contributed
= Min (Internet Bandwidth, Wireless Bandwidth)
by Neighbor
45
Future Work
• Better frame distribution algorithm
– Solve out of order frame reception
•
•
•
•
Other video types (MPEG)
Include audio stream
Extend CStream to support video scaling
CStream system for smart phones
– Aggregate the 3G internet bandwidth
46
Conclusion
• Designed and built CStream
– Aggregate bandwidth from neighbors for better
video streaming
• Effectively utilizes available bandwidth
• Dynamically handles changes in neighborhood
• Detailed evaluation
– Throughput, Playout Time, Startup Delay, Rebuffer
Events, Frame Distribution
47
Thank You
Questions?
48
Backup
49
Short Video
50
Throughput
7354
7000
7096
6000
Throughput (Kbps)
5150
5000
5411
Per Host
Capacity
Constraint
5047
250 Kbps
500 Kbps
4000
2739
1 Mbps
3472
3000
2806
2576
2000
1767
1000
938
477
239
0
0
2 Mbps
3 Mbps
1854
1430
5 Mbps
962
486
1
Number of Neighbors
734
2
51
Playout Time
350
300
Playout time (s)
250
250 Kbps
200
500 Kbps
1 Mbps
150
2 Mbps
3 Mbps
100
5 Mbps
50
0
0
1
Number of Neighbors
2
52
Startup Delay
80
Startup Delay (s)
70
60
250 Kbps
50
500 Kbps
40
1 Mbps
2 Mbps
30
3 Mbps
20
5 Mbps
10
0
0
1
Number of Neighbors
2
53
Rebuffer Events
Neighbors
Bandwidth
0
1
2
250 Kbps
3
3
3
500 Kbps
3
3
3
1 Mbps
3
3
2
2 Mbps
3
2
1
3 Mbps
2
1.3
1
5 Mbps
2
1
0
Maximum Rebuffer Events - 3
54
Frame Distribution
Expected Actual
Expected
Actual
Client – 2 Mbps
Neighbor– 2 Mbps
Client– 2 Mbps
Neighbor– 1 Mbps
Expected
Actual
Client– 2 Mbps
Neighbor1 – 2 Mbps
Neighbor2– 2 Mbps
Expected
Actual
Client – 3 Mbps
Neighbor1– 2 Mbps
Neighbor2 – 1 Mbps
55