Research Abstract:
The focus of this
research is on problems that arise in the context of QoS enabled IP networks
and their use by applications. In
particular, the main theme of the research, is the development of a greater
synergy between potential users of network QoS capabilities, i.e.,
applications, and the design and implementations of those QoS capabilities
(signaling, scheduling and access algorithms) within the network. In order to accomplish such a goal we are
looking specifically at the use and selection of network QoS services and
parameters by applications. The goal here is to identify performance parameters
that are of most significance to applications, and translate that knowledge
into utility curves that can then be used by both applications to select the
appropriate network service, and by the network to make intelligent decisions
on how to best handle an application's traffic in case of resource
contention. This includes not only
assessing sensitivity to traditional QoS parameters such as bandwidth, loss,
delay, and jitter of different types of applications traffic, e.g.,
transactions, audio, video, etc., but also considering more complex scenarios
involving applications with multiple traffic streams which might involve
different (dynamic) resource sharing rules depending on the availability of
network resources.
The research focuses
on the identification of both network and end system QoS capabilities, that are explicitly aimed at better application
support. This requires an iterative
process between applications and the network in order to identify applications
requirements and determine how they can be best met by the network. Of
particular interest in the context of this research, is to develop an
understanding of which engineering support is most useful to applications when
accessing a QoS enabled IP. The
investigation of these issues is being carried out using a rich multimedia
client-server application that combines multiple types of streams, i.e., audio,
video, and data. The benefit of using such an application is not only that the
different requirements of its individual components exercise a wide range of
network QoS capabilities, but also that the dependencies that exist between
streams create a new set of resource sharing requirements. For example, the choice
of which streams to degrade and how degradation should be applied across
streams in the presence of congestion, is likely to depend not only on the
level of congestion, but also on application level semantic.
Another very important
aspect of the research relates to the pricing of services and the impact that
it will have on user behaviour. For that one needs to understand the range of
possibilities presented by the multimedia services in conjunction with the
capabilities of the end system, and how that can be presented to the end user
who will make a choice based upon availability, need and price.
In order to gain an
understanding of these issues, and develop and test the necessary network
mechanisms, this research relies heavily on experiments. Experimentation will
take place in the context of a lab devoted to multimedia and networking, that
includes end-systems as sources of application traffic, and networking
equipment made available by several vendors. Furthermore, work on the design
and implementation of new mechanisms to better support application service
requirements, will and must be done in close collaboration with equipment
vendors so as to facilitate their incorporation and testing on the available
platforms.
Research
Issues: