Management of QoS using MPEG4 DMIF standard

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Management of QoS using MPEG4 DMIF standard

• Amaro Sousa, Institute of Telecommunications, PT
• Guido Franceschini, CSELT, IT

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Outline

• Describe the problem that is underneath this work
• Introduce DMIF as a possible solution for QoS
  management of multimedia communications
• Highlight the main issues that should be
  considered in QoS management
• Report on how DMIF is being assessed as an
  effective mean to manage QoS in multimedia
  communications

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Some facts!

• Truly networked multimedia services are not yet
  commercially available
• One of the reasons is because it is difficult to
  combine the know-how of multimedia technologies
  and network technologies in the same experts

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In the multimedia technologies side

• At the beginning, multimedia application
  developers were used to develop applications for
  stand-alone hardware platforms
• With the advent of World Wide Web, they started
  to develop applications for best effort IP
  networks
• Their main QoS concern is to use video and audio
  coding schemes at the lowest bit rates possible

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In the network technologies side

• There are a significant number of network
  technologies that can support QoS
• Each network technology has its own set of
  parameters for QoS definition and its own way of
  supporting QoS communications
• There is no clear view on what are the
  technologies that will be selected for provision
  of multimedia services in the future

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What is the problem?

• Multimedia application developers dont want to
  develop multimedia services to any particular
  network technology
• Why?
• They have to learn how to deal with QoS in that
  network technology
• They dont know if this investment will have
  return in the future

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One possible solution is DMIF

• Delivery Multimedia Integration Framework (DMIF)
  is Part 6 of MPEG-4 standard
• DMIF defines a Delivery Layer for MPEG-4
  multimedia applications
• DMIF defines a DMIF Application Interface (DAI)
  to be used by the applications
• It is being standardized in a way that can be
  used by non MPEG-4 applications

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The main goals of DMIF

• To hide the delivery technology details to the
  application
• Local storage
• Broadcast sources
• Remote application
• To ensure interoperability in the control plane
  between end-systems

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DMIF communication architecture (1)
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DMIF communication architecture (2)
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QoS in DMIF

• A typical multimedia session encompasses the
  transmission of different media streams in
  different time instants
• Whenever, a bundle of media streams is to be
  transmitted between peer applications, the local
  application requests to local DMIF instance
  appropriate channels to their transmission

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QoS in DMIF (2)

• In the channels request, the application
  specifies the QoS needed for each media stream
  (using DAI level QoS metrics)
• One function of DMIF instance is to map the QoS
  metrics defined at the DAI into the specific QoS
  metrics of the underneath network technology

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MPEG-4 FlexMux tool
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Potential benefits of FlexMux

• Minimise network connections
• Minimise network resources utilisation through
  statistical multiplexing of different media
  streams
• Minimise network protocol overhead

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Managing QoS through DMIF

• Whenever the applications request connections for
  a bundle of media streams
• First, DMIF should decide, based on each
  individual QoS, which streams should be joined in
  the same FlexMux and which streams should be sent
  in separate FlexMux instances
• Then, DMIF should establish an appropriate
  network connection for each created FlexMux

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QoS management - main issues

• Simplicity
• Network resources optimisation
• Minimisation of network protocol overhead
• Minimisation of average number of connections
• Minimisation of impact on overall delivery
  performance

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QoS Management - a trade-off solution

• Grouping different elementary streams in a single
  FlexMux can lead to
• minimisation of network connections but
• network resources waste if the different
  elementary streams finish in different time
  instants
• Minimising network protocol overhead can lead to
  the introduction of higher delay variations
• Different network technologies have different
  trade-offs

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Current work in JUPITER II aims to

• Investigate how DMIF can effectively support
  multimedia communications
• This objective is being pursued through the
  development of DMIF instances for both IP
  networks with RSVP and native ATM networks

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IP/RSVP DMIF implementation

• Usage of controlled load service over UDP sockets
  to provide QoS to media streams
• Overbooking strategy to achieve efficient mapping
  of DAI level QOS into network level QOS
• Usage of best effort service over TCP sockets to
  provide reliability

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Native ATM DMIF implementation

• Usage of DBR connections for QoS provision to
  media streams
• Sustainable cell rate strategy to achieve the
  best trade-off between network resource
  utilisation and packet delay variation
• Usage of UBR connections for media streams with
  no QoS requirements

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By the end of JUPITER II project

• We should be able to
• Propose a common set of DAI level QoS parameters
  useful for an efficient map into network QoS
  parameters of the studied technologies
• Propose appropriate strategies for FlexMux
  management for the two studied network
  technologies