Streaming Video over a Wireless Network So what is the problem!! WPI CS Research Rugby Bob Kinicki November 30, 2004
CC-Wireless Rugby Team <ul><li>prop   hooker </li></ul><ul><li>  Feng Li   Mingzhe Li </li></ul><ul><li>  wireless measure...
Outline <ul><li>Motivation – the Future </li></ul><ul><li>Streaming Video over Wireless  What Problems? </li></ul><ul><li>...
Streaming Video Video Frames
Streaming Video over Wireless Video Frames Wired network AP
Networking Protocol Layers <ul><li>Application Layer: Real Player,Windows Media Player, MPEG </li></ul><ul><li>Transport L...
Measurement and Tools
Wireless Streaming Multimedia Lab Topology   Slide courtesy of Mingzhe’s PEDS presentation Monday October 25,2005
Wireless Measurement Study
Preliminary Wireless Measurements Application Layer Network Layer Data Link Layer
Video Streaming Choices <ul><li>Media Player or Real Player </li></ul><ul><li>TCP or UDP </li></ul><ul><li>Single layer en...
MediaPlayer ™  vs.  RealPlayer ™   A Comparison of Network Turbulence
Real vs WMP Playout Rate RealPlayer  buffers at a higher rate
Video Compression Standard <ul><li>MPEG </li></ul><ul><ul><li>Popular compression standard </li></ul></ul><ul><ul><li>Intr...
340 Kbps Clip - Bottleneck Capacity 725 Kbps < 0.001 packet loss After 15 seconds  TCP  Friendly?
548 Kbps Clip - Bottleneck Capacity 725 Kbps ~ 0.003 packet loss for WSM ~ 0.006  packet loss for TCP after 15 seconds Not...
1128 Kbps Clip - Bottleneck Capacity 725 Kbps Responsive to Capacity?
Wireless Networks
Wireless Issues <ul><li>Higher error rates -  Bursty? </li></ul><ul><li>Hidden terminal problem </li></ul><ul><li>Variable...
Hidden Terminal Problem <ul><li>802.11 Solution to the Hidden Terminal Problem </li></ul><ul><ul><li>Use a four-way handsh...
Rate Constrained TFRC <ul><li>A seven-hop chain network was simulated. </li></ul><ul><li>The TFRC sending rate is  manuall...
Wireless Bandwidth Estimation
Performance Definitions <ul><li>The  capacity , C i  , of hop  i  is the maximum possible IP layer transfer at that hop. N...
Bandwidth Estimation Techniques <ul><li>Variable Packet Size (VPS) probing : used to measure minimum RTT’s to all hops on ...
Packet Dispersion
Bandwidth Estimation Techniques <ul><li>pathchirp : uses an exponentially spaced chirp probing train and launches  m packe...
Bandwidth Estimation and Video <ul><li>Currently, bandwidth estimation used in Windows Media Player </li></ul><ul><ul><li>...
Discussion ?
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Streaming Video over a Wireless Network.ppt

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  • 04/29/10 Need to precisely quantify performance during the buffering period Synching up application and network level measurements is a challenge (even on one host) We came up with a way to parse RTSP packets and application level data to do so. Point out: 1) buffering (loss 2) Not TCP-friendly 3) Responsive to capacity --- NOT FIREHOSE CBR 4) Depends on the encoding rate vs. the capacity (lots of burden on content provider)
  • Streaming Video over a Wireless Network.ppt

    1. 1. Streaming Video over a Wireless Network So what is the problem!! WPI CS Research Rugby Bob Kinicki November 30, 2004
    2. 2. CC-Wireless Rugby Team <ul><li>prop hooker </li></ul><ul><li> Feng Li Mingzhe Li </li></ul><ul><li> wireless measurement wireless bandwidth estimation </li></ul><ul><li> flanker flanker </li></ul><ul><li>Jae Chung Yubing Wang </li></ul><ul><li> congestion control retransmissions </li></ul><ul><li>scrumhalf </li></ul><ul><li>Robert Kinicki </li></ul><ul><li>protocols </li></ul><ul><li> flyhalf </li></ul><ul><li> Huahui Wu </li></ul><ul><li>weak side wing FEC </li></ul><ul><li>Emmanuel Agu </li></ul><ul><li>low-level wireless </li></ul><ul><li>fullback </li></ul><ul><li>Mark Claypool </li></ul><ul><li>multimedia </li></ul>
    3. 3. Outline <ul><li>Motivation – the Future </li></ul><ul><li>Streaming Video over Wireless What Problems? </li></ul><ul><li>Background </li></ul><ul><ul><li>Layered network architecture </li></ul></ul><ul><ul><li>Networking ‘religious’ tenets </li></ul></ul><ul><ul><li>Measurement and Tools </li></ul></ul><ul><ul><li>Streaming multimedia primer </li></ul></ul><ul><ul><li>Introduction to wireless networks </li></ul></ul><ul><li>Focus: Wireless Bandwidth Estimation </li></ul><ul><li>Discussion ?? </li></ul>
    4. 4. Streaming Video Video Frames
    5. 5. Streaming Video over Wireless Video Frames Wired network AP
    6. 6. Networking Protocol Layers <ul><li>Application Layer: Real Player,Windows Media Player, MPEG </li></ul><ul><li>Transport Layer: TCP, UDP </li></ul><ul><li>Network Layer: IP </li></ul><ul><li>Data Link Layer (MAC): 802.3, 802.11b, 802.11g </li></ul>
    7. 7. Measurement and Tools
    8. 8. Wireless Streaming Multimedia Lab Topology Slide courtesy of Mingzhe’s PEDS presentation Monday October 25,2005
    9. 9. Wireless Measurement Study
    10. 10. Preliminary Wireless Measurements Application Layer Network Layer Data Link Layer
    11. 11. Video Streaming Choices <ul><li>Media Player or Real Player </li></ul><ul><li>TCP or UDP </li></ul><ul><li>Single layer encoding or multilayer encoding </li></ul>
    12. 12. MediaPlayer ™ vs. RealPlayer ™ A Comparison of Network Turbulence
    13. 13. Real vs WMP Playout Rate RealPlayer buffers at a higher rate
    14. 14. Video Compression Standard <ul><li>MPEG </li></ul><ul><ul><li>Popular compression standard </li></ul></ul><ul><ul><li>Intra-compression and inter-compression </li></ul></ul><ul><ul><li>Three types of frames: I, P and B </li></ul></ul><ul><ul><li>Group Of Pictures (GOP) </li></ul></ul>
    15. 15. 340 Kbps Clip - Bottleneck Capacity 725 Kbps < 0.001 packet loss After 15 seconds TCP Friendly?
    16. 16. 548 Kbps Clip - Bottleneck Capacity 725 Kbps ~ 0.003 packet loss for WSM ~ 0.006 packet loss for TCP after 15 seconds Not TCP- Friendly!
    17. 17. 1128 Kbps Clip - Bottleneck Capacity 725 Kbps Responsive to Capacity?
    18. 18. Wireless Networks
    19. 19. Wireless Issues <ul><li>Higher error rates - Bursty? </li></ul><ul><li>Hidden terminal problem </li></ul><ul><li>Variable bandwidth </li></ul><ul><li>Mobile versus stationary </li></ul><ul><li>MAC layer saturation </li></ul>
    20. 20. Hidden Terminal Problem <ul><li>802.11 Solution to the Hidden Terminal Problem </li></ul><ul><ul><li>Use a four-way handshake: RTS-CTS-DATA-ACK where the RTS and CTS packets are significantly smaller than the average data packet. </li></ul></ul><ul><ul><li>The maximum number of RTS retransmissions is set to 7. </li></ul></ul><ul><li>However, the 802.11 protocol will still have problems if the MAC layer becomes saturated!! </li></ul>1 2 3
    21. 21. Rate Constrained TFRC <ul><li>A seven-hop chain network was simulated. </li></ul><ul><li>The TFRC sending rate is manually constrained. </li></ul><ul><li>The MAC layer saturates at 300Kbps. </li></ul>
    22. 22. Wireless Bandwidth Estimation
    23. 23. Performance Definitions <ul><li>The capacity , C i , of hop i is the maximum possible IP layer transfer at that hop. Namely, the bit rate for transferring MTU-sized IP packets. </li></ul><ul><li>The available bandwidth , A i , of a link relates to the unused capacity of a link during a time period. </li></ul><ul><li>The Bulk-Transfer-Capacity (BTC) is the maximum throughput obtainable by a single TCP connection. </li></ul>
    24. 24. Bandwidth Estimation Techniques <ul><li>Variable Packet Size (VPS) probing : used to measure minimum RTT’s to all hops on path. </li></ul><ul><ul><ul><li>pathchar, pchar, ... </li></ul></ul></ul><ul><li>Packet pair probing : each packet pair consists of two packets of the same size sent back-to-back. The goal is to measure the dispersion of a packet pair. </li></ul><ul><li>Packet train probing : extends packet-pair probing by using multiple back-to-back packets. </li></ul><ul><li>Self-Loading Periodic Streams (SLoPS) : send a train of packets (k=100) equal-sized packets at a rate R. Sender continues to vary R to get it close to A. </li></ul><ul><li>Trains of Packet Pairs (TOPP) : send many packet pairs at gradually increasing rates from source to sink. </li></ul>
    25. 25. Packet Dispersion
    26. 26. Bandwidth Estimation Techniques <ul><li>pathchirp : uses an exponentially spaced chirp probing train and launches m packet chirps where each chirp is made up of N UDP probe packets each of size P bytes. </li></ul><ul><li>pathchirp discards all chirps with dropped packets! </li></ul>
    27. 27. Bandwidth Estimation and Video <ul><li>Currently, bandwidth estimation used in Windows Media Player </li></ul><ul><ul><li>Capacity estimation before streaming starts </li></ul></ul><ul><ul><li>Uses packet pair </li></ul></ul><ul><li>Mingzhe’s Research : new approach to bandwidth estimation to improve performance of video over wireless networks. </li></ul>
    28. 28. Discussion ?
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