Prognosemetoder – en oversikt - Telenor

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contractor. The project had a big traffic group of experts from
network operators, industry and universities. A high level of
collaboration on ATM traffic issues was established having a
strong influence on the development of this field. A lot of technical
reports were produced dealing with ATM traffic source
models, comparison of buffering schemes in switching blocks,
performance evaluation of switching block architectures and
priority disciplines, network performance studies, analysis of
statistical multiplexing gain, development and evaluation of
UPC and CAC mechanisms, and preparations of performance
tests on the ATM testbed (RATT) developed in the project. The
traffic studies have in some areas supported design choices
made in the development of the equipment.
R2061 EXPLOIT: “Exploitation of an ATM Technology
Testbed for Broadband Experiments and Applications”. The
aims of EXPLOIT are to provide a platform for pilot applications
and broadband experiments, interconnection to other
broadband platforms through development of mappers and
interworking units, and performing traffic experiments to validate
traffic models and dimensioning methods in the areas of
traffic control, resource management and network performance
analysis. EXPLOIT is a follow-up project in RACE II of the
R1022 project with mainly the same partners, and the EXPLOIT
testbed is based on the RATT. The main objectives for the traffic
group have shifted from mostly theoretical work within
R1022 to performing experiments to validate and refine the
methods developed. The project duration is from 1992 to 1994,
with a possible extension into 1995.
R1012 BLNT: “Broadband Local Network Technology”, a project
within the RACE I programme run mainly by Siemens with
the objective to develop a local switch. The development was
supported by studies on traffic control and performance aspects,
like analysis of multi-stage switching networks. The control
functions implemented were influenced by the studies. The
implementation of a Spacing Policer was developed where a
leaky bucket based peak rate policing is combined with a spacing
function.
R1014 ATMOSPHERIC was the third switching system project
within RACE I, with Ericsson as main partner. ATM traffic
issues were also part of this project, dealing with techniques for
network resource allocation and management. The results were
used as input to the building block specifications.
R1083 PARASOL: “ATM Specific Measurement Equipment”.
ATM traffic has to be described by its behaviour on several levels
(connection, burst, and cell level) which differ in time scale
by many orders of magnitude. This complexity, together with the
strict requirements on cell loss ratio in ATM networks, makes
traditional simulation techniques insufficient in analysing ATM
network traffic. Development of ATM measurement equipment
is therefore of major importance for validation and testing of the
performance and the traffic characteristics of ATM systems and
control functions. The main objective of the PARASOL project
has been to develop an ATM specific measurement equipment
consisting of both an ATM traffic generator and an ATM traffic
analyser, providing functions such as measurements of cell loss,
cell delay and cell delay variation. A flexible traffic model used
within the traffic generator was developed to allow specification
of traffic load to be as realistic as possible.
R2024 BAF: “Broadband Access Facilities” is an ongoing
RACE II project. The objective of the project is to contribute to
the development of broadband access facilities at conceptual,
technical and application level for small businesses and residential
subscribers. The project will realise an access network based
on shared fibre technology using a passive optical network
(PON) with a tree structure. One of the main issues is the traffic
performance activity dealing with bandwidth management and
traffic concentration aspects. A Medium Access Control (MAC)
protocol for the PON will be developed and analysed in the project.
The suitability for all possible B-ISDN services is
addressed, in particular Constant Bit Rate (CBR) services with
stringent requirements on cell delay and cell delay variation.
R2032 COMBINE: “Composite Broadband Interworking and
End-to-End Models” is a RACE II project investigating the
interworking of ATM based networks with other networks. Two
DQDB – ATM interworking units and a connectionless server
will be developed and attached to the EXPLOIT testbed mentioned
above. Protocols and networks will be modelled and
analysed to predict the end-to-end performance in heterogeneous
network environments, using both analytical and simulation
models. Traffic experiments related to interworking will be
performed to assess the performance and functionality of the
interworking units and to validate the simulation results
obtained.
R2060 CIO: “Co-ordination, Implementation and Operation of
Multimedia Services” is a RACE II project with the main objective
to specify and implement two advanced multimedia teleservices
as prototypes on various end-systems. The end-systems
will be integrated in selected advanced communication experiments.
The services will be tested and demonstrated in a heterogeneous
network environment. A subtask is devoted to performance
analysis and measurements of transport protocols in
order to obtain Quality of Service (QOS) predictability and tune
the protocol parameters to improve performance. The results
will be utilised to guide the resource reservation schemes.
COST
The objectives of the COST 242 project “Methods for Performance
Evaluation and Design of Multiservice Broadband Networks”
are to co-ordinate and advance European research in the
field, identify performance and network design problems, and
provide solutions by mathematical models, computer tools or
optimisation algorithms. The project is a follow-up of the COST
224 project completed in 1991, is gathering researchers from all
over Europe, and has significant influence on the development of
traffic issues in ATM networks. The COST 224 ended up with a
book published: “Performance evaluation and design of multiservice
networks”. Within COST 242 queuing models for end to
end performance are being developed. Traffic control strategies
are investigated with focus on VBR connections and the relationships
between traffic descriptors, connection admission control
and parameter enforcement. Network design, routing strategies,
network architecture and dimensioning are being considered.
High speed LAN, MAN and interconnection of heterogeneous
networks are evaluated.