Transcript 15Sousa

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
DMIF communication architecture (1)
Broadcast
source
Local
Local
Storage
App
Network
DAI
Remote
App
DAI
AIMS’99 Workshop
Heidelberg, 11-12 May 1999
DMIF Filter
DMIF communication architecture (2)
Local
App
Local DMIF
for Broadcast
Remote DMIF
(emulated)
Remote App.
(emulated)
Local DMIF
for Local Files
Remote DMIF
(emulated)
Remote App.
(emulated)
Local DMIF
for Remote srv
DAI
Sig
map
DNI
Remote
App
Remote DMIF
(Real)
DNI
Heidelberg, 11-12 May 1999
Local
Storage
Network
Sig
map
AIMS’99 Workshop
Broadcast
source
DAI
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
DAI
Header Insertion
FIFO Queue
Packetizer
DNI
Network connection
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 tradeoff 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
AIMS’99 Workshop
Heidelberg, 11-12 May 1999