media streaming performance in a portable wireless classroom network
DESCRIPTION
Media Streaming Performance in a Portable Wireless Classroom Network. Presenter: Jean Cao Supervisor: Carey Williamson TRLabs & Dept. of Computer Science UoC April 14, 2005. Outline. Motivations Media Traffic Characterization Classroom Measurements Extended Experiments: Capacity - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/1.jpg)
Media Streaming Performance in a Portable Wireless Classroom Network
Presenter: Jean CaoSupervisor: Carey WilliamsonTRLabs & Dept. of Computer Science UoCApril 14, 2005
![Page 2: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/2.jpg)
Motivations Media Traffic Characterization Classroom Measurements Extended Experiments:
Capacity Bottleneck The “Bad Apple” Phenomenon
Conclusions Current and Future Work
Outline
![Page 3: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/3.jpg)
MotivationsOn-Line
Education
A French Cinematography
Class Test
Feasible?
Performance Issues?
Note: Citation numbers are referred to the corresponding references of the paper.
Server
ClientClient
Client
Sniffer
Protocol Efficiency?
WirelessLAN
PortableWireless ClassroomNetwork [7, 8, 11]
Multimedia Streaming [1, 2, 3, 4]
![Page 4: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/4.jpg)
MotivationsOn-Line
Education
A French Cinematography
Class Test
Feasible?
Performance Issues?
Note: Citation numbers are referred to the corresponding references of the paper.
Sniffer
Protocol Efficiency?
WirelessLAN
PortableWireless Classroom
Network [7, 8, 11]
Multimedia Streaming [1, 2, 3, 4]
Server
ClientClient
Client
![Page 5: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/5.jpg)
MotivationsOn-Line
Education
A French Cinematography
Class Test
Feasible?
Performance Issues?
Note: Citation numbers are referred to the corresponding references of the paper.
Sniffer
Protocol Efficiency?
WirelessLAN
PortableWireless Classroom
Network [7, 8, 11]
Server
ClientClient
Client
Multimedia Streaming [1, 2, 3, 4]
![Page 6: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/6.jpg)
MotivationsOn-Line
Education
Feasible?
Performance Issues?
Note: Citation numbers are referred to the corresponding references of the paper.
Sniffer
Protocol Efficiency?
WirelessLAN
PortableWireless Classroom
Network [7, 8, 11]
Server
ClientClient
Client
Multimedia Streaming [1, 2, 3, 4]
A French Cinematography
Class Test
![Page 7: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/7.jpg)
MotivationsOn-Line
Education
Note: Citation numbers are referred to the corresponding references of the paper.
Sniffer
WirelessLAN
PortableWireless ClassroomNetwork [7, 8, 11]
Server
ClientClient
Client
Multimedia Streaming [1, 2, 3, 4]
A French Cinematography
Class Test
Feasible?
Performance Issues?Protocol Efficiency?
![Page 8: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/8.jpg)
MotivationsOn-Line
Education
Note: Citation numbers are referred to the corresponding references of the paper.
WirelessLAN
PortableWireless ClassroomNetwork [7, 8, 11]
Server
ClientClient
Client
Multimedia Streaming [1, 2, 3, 4]
A French Cinematography
Class Test
Feasible?
Performance Issues?Protocol Efficiency?
Sniffer
![Page 9: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/9.jpg)
Media Traffic Characteristics Digitized 8 min clip
from movie “Au Revoir Les Enfants (1998)”
Converted to MPEG-4 Audio @ 128 kbps
and 43 fps Video @ 400 kbps
and 30 fps
Total 14,854 video frames Mean frame size
1,641 bytes 90% frames are
[1 KB, 2 KB] 1.4% > 4 KB
![Page 10: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/10.jpg)
Media Traffic Characteristics
Video Source Traffic Profile at Different Granularities:
(a) 1 second (b) 3 seconds (c) 30 seconds (d) 1 minute
Constant Bit Rate @ coarse-grain time scale
Variable Bit Rate @ finer-grain time scale
![Page 11: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/11.jpg)
Classroom Measurements
French cinematography class
System setup IEEE802.11b Ad Hoc Network (11Mbps theoretical
bandwidth) 8 laptops as Clients (mpeg4player) 1 laptop as Server (Apache http server and Darwin
Streaming server) 1 laptop as channel monitor (Sniffer software)
Procedure: Watch the 8 minute movie clip Complete the Web based multiple-choice quiz Review 2 short movie clips while answering questions
![Page 12: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/12.jpg)
Classroom Measurements
Results Conducted successfully
Feedbacks from students are positive
![Page 13: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/13.jpg)
Classroom Measurements
Observations 469,778 packets tx over the
channel 99.3% of UDP and 0.7% of TCP 0.025% CRC errors 0.43% MAC retransmissions First 200 seconds: TCP (RTSP) UDP (RTP) data packets After 10 minutes: TCP (HTTP) Heaviest demand from
multimedia streaming Max throughput is about 4.6
Mbps (vs. 5-6 Mbps effective BW of 11b)
TCP (RTSP)
UDP (RTP)
TCP (HTTP)
UDP (RTP)
4.6 Mbps
Time
Time
![Page 14: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/14.jpg)
Additional Experiments
8 clients saturate the network; and the 9th client degrades the performance of all clients equally.
Bottleneck – the wireless channel
![Page 15: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/15.jpg)
The Bad Apple Phenomenon
Server
Client 1 Client 2 Client 3
![Page 16: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/16.jpg)
The Bad Apple Phenomenon
Server
Client 1 Client 2 Client 3
X
![Page 17: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/17.jpg)
The Bad Apple Phenomenon
Server
Client 1 Client 2 Client 3
X
![Page 18: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/18.jpg)
The Bad Apple Phenomenon
Server
Client 1 Client 2 Client 3
X
One Bad Apple Spoils
the Batch!
![Page 19: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/19.jpg)
The Bad Apple Phenomenon
![Page 20: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/20.jpg)
The Bad Apple Phenomenon
Server Wireless Network Interface Queue
Wireless Channel
MAC Protocol
Client 1
Client 2
Client 3
Drop
X
![Page 21: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/21.jpg)
The Bad Apple Phenomenon
![Page 22: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/22.jpg)
The Bad Apple Phenomenon
Scenario Normal 4 Clients
1 Bad, Retry = 16
1 Bad, Retry = 1
Video rate (fps) 29.96 29.69 29.77Audio rate (fps) 43.09 41.84 42.90Avg skipped video frames (per client statistics)
0(0/0/0/0)
36(37/34/27/46)
2(0/0/0/7)
Avg dropped packets (per client statistics)
0(0/0/0/2)
330( 309 / 320 / 294 / 399 )
80( 80 / 77 / 83 / 729 )
Avg lateness (sec)
2.5 14.5 5.75
Playback Stats at Clients
![Page 23: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/23.jpg)
Conclusions
Portable Wireless Classroom Network is a promising technology for education
Currently, 802.11b network can support limited number of streaming clients, and the bottleneck is at the wireless channel
When system is overloaded, degrading performance for all clients
The “bad apple” phenomenon can seriously degrade multimedia delivery in wireless environments; can a security problem
![Page 24: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/24.jpg)
Current and Future Work
More elegant solutions to the “bad apple” problem Adaptive MDMI (Multiplicative Decrease and
Multiplicative Increase) algorithm Multi-Channel Multi-Rate algorithm
QoS support in Wireless LAN -- keep “bad apple” problem in mind
![Page 25: Media Streaming Performance in a Portable Wireless Classroom Network](https://reader036.vdocument.in/reader036/viewer/2022070419/56815c2a550346895dc9ff8b/html5/thumbnails/25.jpg)
QUESTIONS?