aims’99 workshop heidelberg, 11-12 may 1999 management of qos using mpeg4 dmif standard amaro...
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AIMS’99 Workshop
Heidelberg, 11-12 May 1999
Management of QoS using MPEG4 DMIF standard
Amaro Sousa, Institute of Telecommunications, PT
Guido Franceschini, CSELT, IT
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
What is the problem?
• Multimedia application developers don’t 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 don’t know if this investment will have return in the future
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
RemoteApp
DAI
DMIF communication architecture (1)
Local
App
DAI
Broadcastsource
LocalStorage
Network
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
Sigmap
Remote DMIF(Real)
RemoteApp
DNI DAI
Local
App
DAI
DM
IF F
ilte
r
Local DMIFfor Remote
srv
DNI
Sigmap Network
Local DMIFfor Broadcast
Remote DMIF(emulated)
Remote App.(emulated)
Broadcastsource
Local DMIFfor Local Files
Remote DMIF (emulated)
Remote App.(emulated)
LocalStorage
DMIF communication architecture (2)
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
MPEG-4 FlexMux tool
Header Insertion
Packetizer
FIFO Queue
Network connection
DAI
DNI
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
Potential benefits of FlexMux
• Minimise network connections
• Minimise network resources utilisation through statistical multiplexing of different media streams
• Minimise network protocol overhead
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
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