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Completed/planned activities of AGH in VD-A. Miroslaw Kantor , Marcin Niemiec Department of Telecommunications AGH University of Science and Technology. VD-A meeting February 26, 2007 Barcelona, Spain. Completed/planned activities. Access network resilience (will be continued)
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Completed/planned activities of AGH in VD-A Miroslaw Kantor, Marcin Niemiec Department of Telecommunications AGH University of Science and Technology VD-A meeting February 26, 2007 Barcelona, Spain
Completed/planned activities Access network resilience (will be continued) • Network protection strategies for access networks • Analytical reliability analysis of access networks • Stochastic simulation for evaluation of access networks reliability/availability • System reliability design problem Quantum cryptography (planned) • Study of optical network technologies for adaption of quantum cryptography techniques to optical access networks February26, 2007 Barcelona, Spain
Stochastic simulation approach • In most of the practical cases we cannot specify precisely the model or the value of its parameters • The assumption of deterministic values for the uncertainty might lead to faulty models whose analysis might not be in conformity with reality • Parameter uncertainty is typically specified in terms of probability density functions PDFs February26, 2007 Barcelona, Spain
Types of system resilience performance Considered types of system performance: • s-expected system lifetime: mean system lifetime (expected mean value EMV) • -system lifetime: denotes the largest satisfying the inequality: This means that reaches upwards of with a probability • system reliability: probability that the system lifetime is larger than or equal to the given value February26, 2007 Barcelona, Spain
Passive Optical Network recovery schemes [G.981.5] Recovery architecture of type B Recovery architecture of type A Recovery architecture of type C Recovery architecture of type D February26, 2007 Barcelona, Spain
Reliability block diagrams for PON recovery schemes RBD for recovery architecture of type A RBD for recovery architecture of type B RBD for recovery architecture of type D: duplex RBD for recovery architecture of type C RBD for recovery architecture of type D: no duplex February26, 2007 Barcelona, Spain
Assumptions for stochastic simulation • No element repair action is taken after the failure • The exponential distribution, as one of the most common distributions used in the systems reliability analysis, has been applied • The length of the connection link is 20 km • Survivability parameters of the optical access network components: February26, 2007 Barcelona, Spain
Stochastic simulation results (basic architecture) Stochastic simulation process for EMV PDF of system lifetime February26, 2007 Barcelona, Spain
Results for considered recovery architectures M. Kantor, K. Wajda, P. Cholda: „Reliability Evaluation of PON Recovery Architectures Using Stochastic Simulation”, BBEurope,11-14 December 2006,Geneva, Switzerland February26, 2007 Barcelona, Spain
Planned activity Study of optical network technology and architectures (PON, WDM...) in order to adapt quantum cryptography techniques to optical access networks February26, 2007 Barcelona, Spain
Quantum Cryptography Quantum Cryptography (QC) provides unbreakable communications– each eavesdroped intruders are detected. QC solves key distribution problem over optical fiber networks.QC ensuresabsolute security by using the laws of quantum physics (a bits are coding by quantum states of photons). Currently, QC devices are producing and testing (i.e. in Europe by Id Quantique or SmartQuantum) but these devices communicate upon a dedicated fibre. One of possible applications: FTTH PON technologyuses broadcast downlink communication - each entity receives all the network traffic. Therefore, encryption in these networks is crucial in order to avoid frauds. February26, 2007 Barcelona, Spain
Possible aspects Possible aspects to consider: • Analysis of necessity • Analysis of technical possibility • Requirements • Security issues • Services • Business issues • Case studies • … Contact person: Marcin Niemiec niemiec@kt.agh.edu.pl February26, 2007 Barcelona, Spain
Planned joint activity Topic: Experimental evaluation of access network resilience schemes Paticipants: FUB, AGH Planned mobility: October 2007 February26, 2007 Barcelona, Spain
Conclusions • Different access architectures based on the Passive Optical Network concept have been compared • The comparison was made taking into account three types of system performance measures: s-expected system lifetime, -system lifetime and system reliability • The stochastic simulation was applied for simple PON architecture to check the applicability of this method for reliability analysis of more complicated systems • The obtained results allow us to state that stochastic simulation method can be used for that purpose February26, 2007 Barcelona, Spain