西南师范大学：《计算机网络》课程教学资源（PPT课件讲稿，英文版）Chapter 6 Multimedia Networking

Chapter 6 Multimedia Networking Computer Networking: A Top Down Approach Featuring the Internet The power point slides are based on the material 2nd edition rovided by Jim Kurose. Keith ross Jf Kurose and K.W. ross Addison-Wesley, July 2002

Chapter 6 Multimedia Networking Computer Networking: A Top Down Approach Featuring the Internet, 2 nd edition. Jim Kurose, Keith Ross Addison-Wesley, July 2002. The PowerPoint Slides are based on the material provided by J.F Kurose and K.W. Ross

Multimedia, Quality of service: What is it? Multimedia applications network audio and video Continuous media") Qos network provides application with level of performance needed for application to function

Multimedia, Quality of Service: What is it? Multimedia applications: network audio and video (“continuous media”) network provides application with level of performance needed for application to function. QoS

Chapter 6: Goals Principles o Classify multimedia applications o Identify the network services the apps need o Making the best of best effort service o Mechanisms for providing Qos Protocols and Architectures O Specific protocols for best-effort 口 Architectures for Qos

Chapter 6: Goals Principles  Classify multimedia applications  Identify the network services the apps need  Making the best of best effort service  Mechanisms for providing QoS Protocols and Architectures  Specific protocols for best-effort  Architectures for QoS

Chapter 6 outline 口6.1Mu| timedia 0 6.5 beyond Best effort Networking Applications o 6.6 Scheduling and 口6.25 reaming stored Policing Mechanisms audio and video 0 6.7 Integrated Services O RTSP 06. 8 RSVP 06.3 Real-time g6.9 Differentiated Multimedia: Internet Services Phone case study 口64 Protocols for real- Time Interactive Applications O RTPRTCP SIP

Chapter 6 outline  6.1 Multimedia Networking Applications  6.2 Streaming stored audio and video  RTSP  6.3 Real-time Multimedia: Internet Phone Case Study  6.4 Protocols for Real￾Time Interactive Applications  RTP,RTCP  SIP  6.5 Beyond Best Effort  6.6 Scheduling and Policing Mechanisms  6.7 Integrated Services  6.8 RSVP  6.9 Differentiated Services

MM Networking applications Classes of m applications: Fundamental Streaming stored audio characteristics: and video ypically delay sensitive 2) streaming live audio and o end-to-end delay video delay jitter 3) Real-time interactive But loss tolerant audio and video infrequent losses cause minor glitches 口 Antithesis of data which are loss intolerant Jitter is the variability but delay tolerant of packet delays within the same packet stream

MM Networking Applications Fundamental characteristics:  Typically delay sensitive  end-to-end delay  delay jitter  But loss tolerant: infrequent losses cause minor glitches  Antithesis of data, which are loss intolerant but delay tolerant. Classes of MM applications: 1) Streaming stored audio and video 2) Streaming live audio and video 3) Real-time interactive audio and video Jitter is the variability of packet delays within the same packet stream

Streaming Stored Multimedia Streaming: g media stored at source 口 transmitted to client o streaming: client playout begins before all data has arrived o timing constraint for still-to-be transmitted data: in time for playout

Streaming Stored Multimedia Streaming:  media stored at source  transmitted to client  streaming: client playout begins before all data has arrived  timing constraint for still-to-be transmitted data: in time for playout

Streaming Stored Multimedia What Sit2 2. video sent 1. video 3. video received recorde d network played out at client delay time streaming: at this time, client playing out early part o of video while server still sending later part of video

Streaming Stored Multimedia: What is it? 1. video recorded 2. video sent 3. video received, played out at client streaming: at this time, client playing out early part of video, while server still sending later part of video network delay time

Streaming Stored Multimedia: Interactivity O VCR-like functionality: client can < pause, rewind, FF, push slider bar o 10 sec initial delay Ok o 1-2 sec until command effect OK o RTSP often used (more later) o timing constraint for still-to-be transmitted data: in time for playout

Streaming Stored Multimedia: Interactivity  VCR-like functionality: client can pause, rewind, FF, push slider bar  10 sec initial delay OK  1-2 sec until command effect OK  RTSP often used (more later)  timing constraint for still-to-be transmitted data: in time for playout

Streaming Live Multimedia Examples: g Internet radio talk show o Live sporting event streaming o playback buffer playback can lag tens of seconds after transmission o still have timing constraint Interactivity o fast forward impossible o rewind, pause possible

Streaming Live Multimedia Examples:  Internet radio talk show  Live sporting event Streaming  playback buffer  playback can lag tens of seconds after transmission  still have timing constraint Interactivity  fast forward impossible  rewind, pause possible!

Interactive, Real-Time Multimedia O applications: IP telephony, video conference, distributed interactive worlds O end-end delay requirements o audio: 150 msec good 400 msec OK includes application-level (packetization)and network delays higher delays noticeable, impair interactivity g session initialization o how does callee advertise its ip address, port number, encoding algorithms?

Interactive, Real-Time Multimedia  end-end delay requirements:  audio: < 150 msec good, < 400 msec OK • includes application-level (packetization) and network delays • higher delays noticeable, impair interactivity  session initialization  how does callee advertise its IP address, port number, encoding algorithms?  applications: IP telephony, video conference, distributed interactive worlds