Abstract:
The main objective of the model we describe in this paper
is to allow easy, flexible addition of quality of service (QoS) control
to Java Internet applications. In this work the QoS is expressed in
terms of network and host resources, the network QoS being controlled with
RSVP. Flexibility is provided by a prototype product
from the ANSA research consortium; Reflective Java which uses
the Meta Object Protocol (MOP) to separate functional requirements (what
the application does) from non-functional requirements (how
it does it). This protocol permits the design and implementation
of a generic QoS control element which can be added to an application for
which QoS control is required. Alternatively, an existing
application with rudimentary QoS control can be
modified to use a set of QoS control classes designed by a specialist intended
to reconcile competition for QoS between applications.
The QoS control element we have designed also has scope
for QoS adaptation, moving decisions on the introduction of QoS control
from build-time to run-time when best-effort degrades below
a useful point. Charging is also considered in this work.
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Abstract:
This dissertation describes the work and results of the
project done by Jérôme Tassel at British Telecommunication
(BT) research labs for the M.Sc in distributed systems degree at the University
of Kent at Canterbury. The objectives of the project were to evaluate Reflective
Java, QoS management and charging as well as the emerging Internet Integrated
Services Architecture.
The main achievement of this project is a Java QoS control component which is a prototype version of a QoS management model (QoteS) based on Reflective Java that we have designed The main objective of this model is to allow easy, flexible addition of Quality of Service (QoS) control to a real-time Java Internet application. Flexibility is provided by a product from the ANSA research consortium: Reflective Java, which uses the Meta-object Protocol (MOP) to separate functional requirements (what the application does) from non-functional requirements (how it does it). This scheme permits the design and implementation of a generic QoS control element, which can then be added to an application for which QoS control was not originally required but now is. Such applications might be collaborative tools where requirements have moved from a text-based interface to a multimedia interface using audio and video streaming facilities. Alternatively, an existing application with rudimentary QoS control can be modified to use more professionally produced QoS control classes intended to reconcile competition for QoS between applications. The QoS control element that we designed also has scope for QoS adaptation, including the dynamic introduction of QoS control at run-time if best effort service degrades below a useful point. We believe this model provides a flexible way to control the usage of the resources available to the users down to a very finely grained level.