Discrete Mathematics Operating Systems Computer Networks

  #1 Introduction Semester Ganjil 2012

PTIIK – Universitas Brawijaya Discrete Mathematics Operating Systems Computer Networks Advance Networking

  Network Analysis Network Programming Distributed Systems Server and System Administrations

  Multimedia Networking Network Security

  

Today’s Lecture

• This Course
• – Goals – Outline/Schedule
• – Grading Policy
• Introduction to Multimedia Networking

  

References

• Kurose & Ross, “Computer

  th

Networking : Top down Approach”, 6

Ed., Pearson/Addison, 2012.

• Tanenbaum, “Computer Networks”,

  th 5 Ed., Prentice, 2010.

• Hofmann & Beaumont, “Content Networking”, Morgan, 2005.
• Rosenberg, “A Primer of Multicast Routing”, Springer, 2012.
• O’Driscoll, “Next Generation IPTV Service and Technologies”, Wiley,

  

Goals

• Who can take this class?
• – Almost anyone

• • Learn the structure of networks and protocols

  used for transporting multimedia data
• Prerequisites:
• – Minimum: Have taken “Computer Networks” class
• – Helpful: if already taken “Advance Networking” class

Outline of this Course • #1 Introduction to Multimedia Netw

• #2 Multimedia Netw. Apps • #3 Requirements of Multimedia Netw.
• #4 Coding and Compression • #5 Real-time Transport Protocols • #6 Live Streaming: IP Multicast • #7 Live Streaming: IP Multicast (cont’d)
• #8 Live Streaming: Overlay Multicast • #9 CDN: Solutions • #10 CDN: Case Studies • #11 QoS on the Internet: Constraints • #12 QoS on the Internet: Solutions • #13 Discussion • #14 Summary

  

Grading Policy



  Classes −

  Two (2) Credits 

  Exercises (assistant required) −

  One (1) Credit 

Evaluation 

  Homework 15% _ Paper Reading and Presentation 30% _ MidTerm Test 20% _ Final Exam 35%

  #1 Introduction to

Multimedia Networking

  

Outline of Introduction

• Trend of Global Internet Traffic • What is Multimedia • What is Multimedia Networking

  Today’s Internet Video Traffic

Source: http://www.internetobservatory.net/

  

Cisco VNI 2011-2016: “Globally, Internet Video traffic will

be 55% of all consumer traffic in 2016, up from 51% in 2011” [ http://www.cisco.com/go/vni ]

  

Overview

What is Multimedia?

  What is Multimedia

• Characteristics of multimedia
• Various media types

  What is Multimedia networking? What is Multimedia networking

• User requirements of multimedia applications on the network
• Technologies associated with multimedia networking
• Overall structure of multimedia

  

What is multimedia?

• Definition of multimedia
• – is an integration of text, graphics, still image and moving images (video), animation, audio, and any other medium

  where every type of information can be

  represented, stored, transmitted and processed digitally
• – is media and content that uses a combination of different content forms. …

  wikipedia.com

• Characteristics of multimedia
• – Digital – key concept
• – Integration of multiple media types, usually

  

Various Media Types

• • Text, graphics, image, video, animation,

  audio, etc.
• Classifications of various media types
• – Captured vs. synthesized media
• Captured media (natural) : information captured from the real world (still image, video, audio)
• Synthesized media (artificial) : information synthesize by the computer (text, graphics, animation)
• – Discrete vs. continuous media
• Discrete media: spaced-based, media involve the space dimension only ( Text, Image,

  Graphics )

• Continuous media: time-based, media involves

Classification of Media Type Audio Video Animation

  Audio Video Animation Continuo

  Continuo us us

  Text Graphics Text Graphics

  Image Image

  Discrete Discrete Captured Synthesized

  From real world By computer Multimedia: audio  analog audio signal sampled at constant _{quantization error quantized} rate _{value of}

   telephone: 8,000 _{p lit u} ^{d e analog value} samples/sec _{m a signal analog}

   CD music: 44,100 _{ig n s} ^{a l} samples/sec _{a u d io}  each sample quantized, i.e., _time rounded _{sampling rate} ^{8 (N sample/sec)}

   e.g., 2 =256 possible quantized values

   each quantized

  Multimedia: audio  example: 8,000 samples/sec, 256 _{quantization quantized} quantized values: error _{e analog value value of} 64,000 bps _{lit u d}

   ^p receiver converts bits _{l a m signal analog} back to analog signal: _{n a} ^{s ig}

   some quality _{u d io} reduction _{a time} example rates _{(N sample/sec) sampling rate} 

  CD: 1.411 Mbps 

  MP3: 96, 128, 160 kbps 

  Internet telephony: 5.3 kbps and up

  spatial coding example: instead Multimedia: _{values: color value (purple) and color (all purple), send only two of sending N values of same} video _{number of repeated values (N)}

• video: sequence of

  ……………………...… ……………………...…

  images displayed at constant rate

• – e.g. 24 images/sec
• digital image: array of pixels
• – each pixel

  frame i

  represented by bits

• coding: use redundancy

  within and between _{instead of sending temporal coding example:}

  images to decrease # _{complete frame at i+1,} bits used to encode _{frame i send only differences from} image

• – spatial (within

  spatial coding example: instead Multimedia: _{values: color value (purple) and color (all purple), send only two of sending N values of same} video _{number of repeated values (N)}

   CBR: (constant bit

  ……………………...… rate): video encoding

  ……………………...… rate fixed

  

  VBR: (variable bit rate): video encoding rate changes as amount of spatial, temporal coding changes frame i

   examples:

   MPEG 1 (CD-ROM) _{temporal coding example:}

  1.5 Mbps _{instead of sending} ^{complete frame at i+1,}

   MPEG2 (DVD) 3-6 _{send only differences from} Mbps _{frame i}

   MPEG4 (often used

  

Multimedia networking: 3 application

types

• streaming, stored audio, video
• – streaming: can begin playout before

  downloading entire file

• – audio/video will be rendered (implies storing/buffering at client) e.g., YouTube, Netflix, Hulu –

  stored (at server): can transmit faster than

• interactive nature of human-to-human

  conversational voice/video over IP

• – conversation limits delay tolerance e.g., Skype –
• streaming live audio, video

  e.g., live sporting event (futbol) –

  Networked Multimedia

• Local vs. networked multimedia
• – Local: storage and presentation of multimedia information in standalone computers
• Sample applications: DVD
• – Networked: involve transmission and distribution of multimedia information on the network
• Sample applications: videoconferencing, web

  A scenario of multimedia Image server video broadcasting, multimedia Email, etc. networking

  Internet Internet

  Video server

  Multimedia over Internet VoIP Video Conference Intern et Wireless Wireless _{Video Clip}

  Browsing Browsing _Attachment E-mail Informat Music

  Digital Photos Movies ion Finance, Streami Streami Search Brokerag ng ng e Consideration of Networked Multimedia

• Fundamental Characteristics of multimedia information

  data volume

• – Large
• – Typically delay sensitive
• – But loss tolerant
• infrequent losses cause minor glitches
Consideration of Networked

Multimedia

packet

• Properties of current Internet (

  switched networks )

• – Suitable for unexpected burst of data
• no need to establishing an explicit connection
• – Limitation of bandwidth
• Bandwidth is shared statistically so data can be sent at any time
• Causing Queuing delay, especially when congested

  network

• – Best effort
• IP network is not reliable
• cannot guarantee quality of multimedia applications
• – Heterogeneity
• Different user requirements
Requirements for Networked Multimedia

  Challenges of multimedia

networking

• Conflict between media size and

  bandwidth limit of the network user

• Conflict between the

  requirement of multimedia application and the best-effort networ k to meet different requirements

• How

  of different users?

  Technologies of Multimedia

Networking

• Media Compression

  

Media Compression – reduce the

  data volume Address the1st challenge

• – Image compression
• – Video compression
• – Audio compression
• Multimedia Transmission

  Multimedia Transmission

nd rd

Address the 2 and 3 challenges

• – Protocols for real-time transmission
• – Rate / congestion control

  Multimedia Networking

Systems

• Live media transmission system
• – Capture, compress, and transmit the media on the fly
• Send stored media across the network
• – Media is pre-compressed and stored at the server. This system delivers the stored media to one or multiple receivers.
• Differences between the two systems
• – For live media delivery:
• Real-time media capture, need hardware support
• Real-time compression– speed is important
• Compression procedure can be adjusted based on network conditions
• – For stored media delivery
• Offline compression – better compression result is important

Generic Media Streaming System

  Compressed Input video Streaming

  Video Video Server

  Encoder Internet Internet

  Error control, rate control can be done here to improve QoS

  Compressed Video Video Packets Video Display Video Receiver

  Decoder Error control, provide feedback to the sender