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University: Oxford Brookes
Professor: David Duce
Department: Multiservice Systems Group, School of Computing and
Mathematical Sciences.
Project Outlines
Currently we are carrying out a number of projects
that are all concerned with providing multiservice in packet switched
network. Although each may be focused on one particular aspect of this
subject, they are all interconnected, and directed toward one main
overall goal. Most of the work involves some form of traffic
characterisation and the use of queueing models. The details are as
follows:
1.
To evaluate the relative effectiveness of WFQ and CBQ in
supporting all types of traffic in multiservice packet switched
networks, and to consider the possible hybridisation of these schemes in
order to provide the most optimal support for multimedia traffic. OPNET
is being used to build detailed models of both systems.
2.
To investigate the problems of mapping IPv6 flows onto ATM VCs
and providing seamless end-to-end QoS. OPNET is being used to build an
end-to-end model of IPv5 flows that are carried across an ATM network.
3.
To investigate the requirements of network level support for
adaptive continuous media applications, and to develop appropriately
responsive congestion indication mechanisms. OPNET is being used to
evaluate the effectiveness of different feed back trigger mechanisms. A
model of a feed back system that employs FCI has been built for this
purpose.
4.
To investigate the use of dynamic routing methods to provide
service guarantees whilst minimising the use of signalling. This project
is in the early stages and will be considering a combination of
measurement based Flow Admission Control (FAC) and QoS Based Routing to
provided resource allocation to continuous media traffic without the use
of a resource reservation protocol such as RSVP. OPNET will be used to
build detailed models of the FAC mechanism, as well as higher-level
models of the network to test the effectiveness of the dynamic routing
algorithms.
5.
The Large-scale DVEs are attracting increasing attention, not
least from the simulation community (for example battleground
simulation). There are also strong similarities between DVEs and
distributed multiuser games. The research investigates whether Active
Networks might offer potential solutions to scalability issues for large
scale Distributed Virtual Environments.
The graphics issues of
DVEs are considered. Intelligent
message pruning within an active router is exploited for 3D content
messages.
The pruning requirements change much more rapidly in the virtual world
as a consequence of “actors” moving from social group to social
group or place to place, with consequent overheads associated with
joining and leaving multicast groups. This may be thought of as rapid
change in the topology of the virtual world. The topology of the
physical network, the way in which physical devices and people are
connected, change much more slowly. The first research question then is
therefore whether the Active Network approach can benefit this situation
and offer improved performance and flexibility over conventional
approaches, especially in cases where physical users are connected via
heterogeneous links.
Level of detail approach
in geometric modeling in DVEs is similar to conventional approaches to
adaptive video distribution. In DVEs, nearby viewers expect more detail
of an object than distant viewers. Therefore there is no need to
transmit highly detailed representations to the remote in terms of
virtual world users.
The aim of the research
is to identify an architecture, a messages structure, active header
structure and filter set to enable messages to be filtered by Active
Routers in order to achieve level of detail (LOD) filtering. Filtering
mechanisms on active routers for LOD and progressive meshes (PM)
transmission have been proposed.
Simulation tool OPNET
was used to build several simulation models (LOD model for one node, PM
model for one node, and PM model for the multicast group). The
experiments for different scenarios were carried out.
The next stage of the
research requires completion of more experiments for different network
parameters and larger scales of the DVE application.
6.
There are two new PhD students who have recently started working
on mobile ad hoc networks. Their research particularly focuses on the
cross layer design issues.
In addition to the PhD students, a number of MSc
students will be also be addressing certain aspects of the work for
their dissertation.
Publications
Click
a link to view the publication online in Adobe
Acrobat 4.0 format.
F.Ball,
P.Callinan, D.D.Kouvatsos and C Skianis "Dynamic dimensioning
for guaranteed services in packet switched networks." IFIP 6th
Workshop on Performance Modelling and Evaluation of ATM Networks, (20th-22nd
July 1998) Ilkley, UK.
S.
Tater and F.Ball, "Reactive Congestion
Control for Adaptive Continuous Media". The Second GEMISIS
Technical Symposium on "Multimedia-Network-Technology", (17th
&18th May 1999) Salford, UK.
K.Basu
and F.Ball, "Mapping IPv6 Flows onto ATM VCs", The Second
GEMISIS Technical Symposium on "Multimedia-Network-Technology",
(17th &18th May 1999) Salford, UK.
P.Callinan
and F.Ball," Sorted Priority or Class Based Queueing: Which
Way Forward to Support Integrated Services", The Second GEMISIS
Technical Symposium on "Multimedia-Network-Technology", (17th
&18th May 1999) Salford, UK.
F.
Ball. and P.Callinan, "Supporting Guaranteed Services in Packet
Switched Networks: a study of Two alternative methods", International
Conference on Parallel and Distributed Processing Techniques Applications
PDPTA '99, vol. 5, H.R. Arabnia (Ed), ISBN 1-892512-13-0.
F.Ball,
P. Callinan and M Witwit, "A Study of the Options for Bandwidth
Partitioning in Multiservice Networks" IEE Colloquium on Control
of Next Generation Networks, (18th Oct 1999) London, UK.
F.
Ball and S. Tater, "Supporting
Adaptive Video Applications in Future IP Networks" To be presented
at the European Workshop on DISTRIBUTED IMAGING (18th -19th Nov 1999)
London, UK.
S Tater
and F.Ball, "Meeting the
Needs of Adaptive Video Applications in Packet Switched Networks",
18th IASTED International Conference Applied Informatics AI'2000 (14th-17th
Feb 2000) Innsbruck, Austria.
P.
Callinan, M.Witwit, F. Ball, "A Comparative Evaluation of Sorted
Priority Algorithms and Class Based Queueing using Simulation",
Advanced Simulation Technologies Conference ASTC 2000, (16th-20th April
2000) Washington DC.
Maqousi, S. Tater and F. Ball, “Traffic Monitoring Techniques
For Measurement Based Flow Acceptance Control”, 35th Annual Simulation
Symposium, 14 – 18 April, 2002, San Diego, California
Maqousi and F. Ball, “Measurement Flow Admission Control
for Supporting Guaranteed Services in Class Based Queuing”, The
Engineering and Physical Sciences Research Council Postgraduate Networking
Conference (EPSRC PGNET 2002), June 2002, Liverpool, UK.
Maqousi and F. Ball, “The Development and Evaluation of
a Monitoring Technique for M-FAC”, International Journal of Simulation,
Systems, Science & Technology, Vol. 3 No 1-2 June, 2002 UK, ISBN:
1473-8031.
K. Basu, F. Ball and D.D. Kouvatsos, "A Simulation Study
of IPV6 to ATM Flow Mapping Techniques". SCS Transaction Journal
on Network Modeling and Performance Issues, Vol. 78, Issue 7, pg. 423-430,
2002
T. Balikhina, F. Ball and D. Duce, “Active Network Support
for Distributed Virtual Environments”, The Engineering and Physical
Sciences Research
Council Postgraduate Networking Conference (EPSRC PGNET 2002), June
2002, Liverpool, UK.
T. Balikhina, F. Ball and D. Duce, “Distributed Virtual
Environments – An Active Future?”, Eurographics UK 2002, 11th
– 13th June, Leister, UK .
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