The Final Report of AIIS Pilot Project Videoconferencing

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The Final Report of AIIS Pilot ProjectVideoconfer
encing
The2nd AIIS meeting Bandar Seri Begawan, Brunei
Darussalam, 5-9th August 2002

• Apipol GUNABHIBAL
• Engineer
• TOT Corporation Public Company Ltd.

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Agenda

• Objectives
• What is Videoconferencing?
• Standard Issues
• TOTs Videoconferencing system
• Performance Issues
• Conclusion

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Objective

• To evaluate the support of 2-way integrated
  collaboration system in broadband environment

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What is Videoconferencing?

• Videoconferencing is the combination of dedicated
  audio, video and communications networking
  technology for real-time interaction, and is
  often used by groups of people who gather in a
  specific setting (often a conference room) to
  communicate with other groups of people.

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Standard Issues

• The ITU-T H series (ex. H.320, H.323, H.324
  etc..) are the family of the core technologies
  for multimedia teleconferencing
• The ITU-T T.120 series address real time data
  conferencing (Audiographics) portion of a
  multimedia teleconference

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Standard Issues

• H.323 is a cornerstone technology for the
  transmission of real-time audio, video, and data
  communications over Internet Protocol (IP) network

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Standard Issues
H.323 Components (1)

• H.323 Systems document, describes overall
  operation and procedures for H.323 systems
• H.225.0 Specifies messages for call control
  including signaling, registration and admissions,
  and packetization
• H.245 Specifies messages for opening and closing
  channels for media streams
• H.450 Series of Supplementary service
  recommendations

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Standard Issues
H.323 Components (2)

• H.235 Defines the security framework used to
  provide authentication, encryption and integrity
  to the systems
• H.332 Provides large scale, or loosely-coupled
  conferencing based upon H.323
• H.26x Specifies the video codec for audiovisual
  services
• G.711, 72x Specifies the audio codec for
  audiovisual services

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Standard Issues
H.323 Protocol Structure
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Standard Issues
H.323 Elements of The Systems

• Terminal
• MCU manage multipoint conferences
• Gateway interfaces the H.323 system to other
  networks
• Gatekeeper admission control, address
  translation, management of Gateway.
• Border Elements exchange information between
  administrative domains.

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TOT s Videoconferencing System

• Terminal Specification
• H.323 compliant with multimedia codec hardware
  board, video camera, speakers and microphone
• Video Transmission
• H.261 standard coding protocol
• Audio Transmission
• G.711 and G.722 standard coding protocol
• Sound quality enhancement algorithm was
  integrated

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TOT s Videoconferencing System

• Data Conferencing
• software based T.120 compliant
• exchanging, editing and sharing many kind of
  resources (file transfer, instant messaging,
  whiteboard sharing, etc.)
• Communication
• native ATM network conformance in accordance with
  H.323 Annex C (RTP over AAL5)

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TOT s Videoconferencing System
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TOT s Videoconferencing System

• Network Specification
• 6 ATM core switches (3 for Metropolitan
  area)connect together via STM-4 link in the form
  of Star topology (PNNI 1.0 signaling-ATM Forum)
• 32 ATM edge switches (23 for Metropolitan
  area)connect directly to core switch (for each
  region) via STM-1 link in the form of the Star
  topology
• support UNI signaling ver. 3.1, 4.0 (ATM Forum)
  and Q.2931 (ITU-T)

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TOT s Videoconferencing System
Network Configuration
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Performance Issues

• QoE (Quality of Experience) is defined as the
  totality of QoS mechanism, provided to ensure
  smooth transmission of real-time multimedia over
  IP networks.
• AQoS Application-based QoS
• NQoS Network-based QoS
• The quality of an end users experience is the
  true litmus test of a proper audio/video
  deployment

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Performance Issues
Application-based QoS

• Provided by audio/video terminal to enhance the
  desired end-to-end performance
• AQoS and call signaling (H.225, H.245)to
  optimizing processing delay and to improve
  signaling reliability
• AQoS and media handling (H.245)to provide QoS
  services through its measuring and notification
  services

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Performance Issues
Network-based QoS

• Provided by the network and the networking
  elements to enhance end-to-end QoS
• CLR (Cell Loss Ratio)
• CTD (Cell Transfer Delay)
• CDV (Cell Delay Variation)
• Policing mechanism, to police the resource usage
  of each user (SCR, MBS,.. etc.)

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Performance Issues
ATM class of service
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Performance Issues
How the AQoS and NQoS works ?
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Performance Issues
Audio Quality

• 3 elements emerge as the primary factors
  affecting the audio quality
• Clarity a voice signals fidelity, clearness,
  lack of distortion and intelligibility
• End-to-End Delay the time it takes a voice
  signal to travel from talker to listener
• Echo the sound of the talkers voice returning
  to the talkers ears

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Performance Issues
Video Quality

• 2 factors primarily affect perceived video
  quality
• Frame rate average time interval between picture
  frame, variation of the time interval are also
  concerned (frame jitter)
• Spatial Resolution depends on codec algorithm
  (H.261, H.263), high resolution is important in
  some case (document exchange, electronics slide,
  etc.)

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Performance Issues
Relationship of audio/video quality and QoS

• Clarity packet loss and audio codec algorithm
• End-to-End Delay provided by NQoS function
• Echo deploying the echo canceller
• Average Frame Rate and Frame Jitter bandwidth
  requirement, processing and propagation delay

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Performance Measurement
Performance testing

• Videoconferencing terminal access to the network
  through an edge switch
• Define traffic class rt-VBR for virtual channel
  with QoS parameter
• CLR - 10-3
• CTD - lt 150 ms
• CDV - lt 150 ms

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Performance Measurement
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Performance Measurement
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Performance Measurement
Performance ratings from 30 samples, score 1-7
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Conclusion

• To achieve the performance at the acceptable
  level, QoS features should be enabled
• QoS features could be provided through terminal
  and network and its complimentary
• ATM-based transport network provide QoS guarantee
  through the AAL architecture and the policing
  mechanism

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Conclusion

• Demand of multimedia interactive application over
  packet network will be increased gtgt H.323 vs. SIP
  ??
• Everything converge to IP, IP has its own QoS
  technology (RSVP, ISA, DSCP, QOSPF, etc.), How
  could IPs QoS passage be mapped to the legacys
  QoS features??? (Tag Switching technology)

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• For any inquiry, question and comment
• contact tot_vc_at_hotmail.com
• or Apipol GUNABHIBAL
• TOT Corporation public Company Ltd.
• 89/2 moo3 Chaengwattana Rd.
• Laksi BKK 10210
• Tel - 66-2505-2435
• Fax - 66-2574-8401

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THANK YOU