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Tutorial T5
Photonic network availability
Prof. Branko Mikac, Robert Inkret, Marije Ljolje, Marko Lackovic
University of Zagreb, Croatia

Date: Friday, June 13, 2003, 9:00-10:30
Location: Faculty of Electrical Engineering and Computing
Duration: 1.5 hours (no coffee-breaks)
Registration fee: 75 EUR

ABSTRACT

Availability is an important performance feature of a telecommunication system and network. Failures of components could cause interruption of telecommunication services, thus diminishing user satisfaction and generating losses to network operator.
Basic definitions of reliability, availability and security are done, as well as related measures: failure rate, fit, repair rate, MTTF, MTBF, MTTR and MDT. Availability is analysed by bottom up approach which includes levels of components, system and network. Availability structures are considered, taking into account different options of introducing redundancy. Availability models are mostly based on Markov model of repairable systems. All relevant parameters influencing availability function are considered, especially dependency and disjointedness of failure occurrences.
Availability data of optical components are listed. Availability models of photonic network are described concerning hierarchy of instances: wavelength channel, wavelength path, logical channel and logical connection. Behaving of the network instances in the case of failure are described by Boolean expressions. Usual assumptions and approximations in the models are done. Different topologies and protection & restoration scenarios in photonic network are analyzed.
In availability evaluation two basic approaches are used: analytical and simulation (Monte Carlo). In order to find how part of a network influence on total availability figure sensitivity analysis could be used. Examples of topologies and scenarios will be explained: point-to-point photonic communications systems, WDM systems with(out) protection, photonic rings based on WDM, WDM meshed photonic networks and p-Cycles. Tools for availability modeling and evaluation are described.

TUTORIAL OUTLINE

Photonic network availability

1. Definitions and measures
2. Component reliability
3. System availability
4. Network availability
5. Availability structures and models
6. Availability data of optical components
7. Availability modeling of photonic networks
8. Hierarchy of instances
9. Protection & restoration scenarios
10. Availability evaluation approaches
11. Sensitivity analysis
12. Examples of topologies and scenarios
13. Tools for availability modeling and evaluation

SPEAKER'S BIOGRAPHY

Branko Mikac received his B. Sc., M. Sc. and Ph. D. in Electrical Engineering from the University of Zagreb, Croatia, in 1970, 1980 and 1986, respectively. In 1974 he joined the Faculty of Electrical Engineering, University of Zagreb. Since 1992 he works at the Faculty as a Professor at the Department of Telecommunications. He is currently Head of Telecommunications Department. His research interests include reliability of telecommunication systems, fault diagnosis of digital systems, digital transmission systems and optical networks. He also acts as a Scientific Secretary of the European project COST 266 Advanced Infrastructure for Photonic Networks, which deals with research on modeling and evaluation of optical network availability.

Robert Inkret received his B.Sc and M.Sc. at the Department of Telecommunications of the Faculty of Electrical Engineering and Computing, University of Zagreb, in 1995 and 1998 respectively. He is with the Faculty of Electrical Engineering and Computing as an assistant since January 1996. His research interests include design of optical transport networks, object oriented design and general heuristic search techniques.

Marije Ljolje was born in 1976 in Sarajevo, Bosnia and Herzegovina. He received B. Sc. degree in 2001 at the Faculty of Electrical Engineering and Computing, University of Zagreb, Croatia. He now works at the Department of Telecommunications as assistant. His research interests include optical networks, optimization and simulation.

Marko Lackovic was born in Zagreb, Croatia, where he studied at the Faculty of Electrical Engineering and Computing, University of Zagreb. He received his B. Sc. degree in 2002. He currently works at the Department of Telecommunications. His research interests include optical network design, optimization and simulation and availability/reliability analysis.

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