The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Carla Raffaelli - One of the best experts on this subject based on the ideXlab platform.
-
exploitation of dwdm for optical Packet switching with quality of service guarantees
IEEE Journal on Selected Areas in Communications, 2002Co-Authors: Franco Callegati, G E Corazza, Carla RaffaelliAbstract:This paper addresses the problem of building optical Packet switches that are able to effectively cope with variable length Packet traffic and quality of service management, therefore able to support IP traffic. The paper aims at showing that the availability of dense wavelength division multiplexing is crucial. By suitably exploiting the wavelength dimension a multistage fiber delay line buffer can be implemented, with fine granularity and long delay with an architecture of limited complexity. This is necessary to fulfill the buffering requirements of variable length Packets. Furthermore, the wavelength domain is proved to be more effective than the time domain to manage different levels of quality of service. Algorithms are presented that are peculiarly designed for this environment showing that they can effectively differentiate the Packet Loss Probability between three priority classes.
-
input output buffered replicated banyan networks for broadband switching applications
European Transactions on Telecommunications, 1993Co-Authors: G Corazza, Carla RaffaelliAbstract:A switching architecture suitable for broadband applications, employing R-replicated Banyan interconnection networks with input and output buffering, is presented. Various sol- utions for traffic management among the replicated networks and buffer allocation are consi- dered and their performances evaluated by means of an analytical model based on Markov chain representations of input and output buffers. The main results regard evaluation of maximum throughput, delay and Packet Loss Probability by varying operating and design parameters. It has been shown that our architecture satisfies broadband switching operating requirements, with a suitable choice of design parameters, and also performs better than other architectures presented in literature. These considerations suggest that the investigated architecture is very interesting for the implementation of a broadband switch and should be compared with other solutions in an economic perspective.
S.t. Chanson - One of the best experts on this subject based on the ideXlab platform.
-
Packet Loss Probability for bursty wireless real time traffic through delay model
IEEE Transactions on Vehicular Technology, 2004Co-Authors: K.k. Lee, S.t. ChansonAbstract:In this work, two Markov chains modeling Packet delay have been developed to obtain closed-form solutions for Packet Loss probabilities and Packet delay distributions in a real-time wireless communication environment. Packets with delay constraints are queued at the source and are transmitted one by one with possible retransmissions to correct errors. The first model models Packet delay and correlated Packet arrivals using a one-dimensional Markov chain. Usually, at least two dimensions are needed in queuing models. The second model is a two-dimensional Markov chain modeling Packet delay, correlated channel errors, and correlated arrivals. Both correlated errors and arrivals are known to have significant impact on Packet Loss. Possible applications of the results are also discussed.
-
Packet Loss Probability for real-time wireless communications
IEEE Transactions on Vehicular Technology, 2002Co-Authors: K.k. Lee, S.t. ChansonAbstract:A novel Markov model is constructed to calculate the Packet Loss Probability and the delay distribution of real-time wireless Packets. These Packets are transmitted through an erroneous channel modeled by a two-state Markov chain. If a Packet transmission is not successful, the Packet is retransmitted until a delay limit is exceeded. At that time, the Packet is discarded and the transmission of the next Packet begins. This Packet-dropping process has a significant impact on Packet Loss Probability but is seldom considered in other Markov models. Closed-form solutions are obtained, and simplified expressions assuming highly correlated errors and small error Probability are derived. Under these conditions, it is found that the Packet Loss Probability is significantly affected by the delay limit and the transition Probability of the channel's remaining in the failure state. On the other hand, the Probability is almost independent of the arrival rate provided the rate is not close to one.
Marco Listanti - One of the best experts on this subject based on the ideXlab platform.
-
cost evaluation of optical Packet switches equipped with limited range and full range converters for contention resolution
Journal of Lightwave Technology, 2008Co-Authors: V Eramo, Marco Listanti, A GermoniAbstract:Two architectures are proposed for a wavelength-division multiplexed optical Packet switch equipped with both limited-range wavelength converters (LRWCs) and shared full-range wavelength converters (FRWCs). The FRWCs are used to overcome the performance degradation in terms of Packet Loss Probability due to the use of LRWCs only. Two different sharing strategies of the FRWCs are considered. In the first architecture, a pool of FRWCs is shared among the arriving Packets. In the second one, the sharing is only partial and the Packets directed to the same output share a same pool of FRWCs. A probabilistic model is proposed to dimension the number of shared FRWCs so that the same Packet Loss Probability of a switch equipped with only shared FRWCs is guaranteed. After introducing a cost model of the converters depending on the conversion range, we show that the architectures may allow a conversion cost savings on the order of 90%.
-
Packet Loss in a bufferless optical wdm switch employing shared tunable wavelength converters
Journal of Lightwave Technology, 2000Co-Authors: V Eramo, Marco ListantiAbstract:We propose an architecture for a bufferless Packet optical switch employing the wavelength dimension for contention resolution. The optical Packet switch is equipped with tunable wavelength converters shared among the input lines. An analytical model Is proposed in order to determine the number of converters needed to satisfy prefixed Packet Loss Probability constraints. This analytical model very accurately fits with simulations results. A sensitivity analysis of the required number of converters as a function of the main system parameters (number of input and output lines, number of wavelengths, ...) and traffic parameters has been carried out. Making use of the introduced dimensioning procedure we have observed that the proposed architecture allows a saving in terms of employed number of converters with respect to the other architectures proposed in literature. Such a saving can reach about 95% of the number of converters.
P L Chu - One of the best experts on this subject based on the ideXlab platform.
-
analysis of partially shared buffering for wdm optical Packet switching
Journal of Lightwave Technology, 1999Co-Authors: Juan Diao, P L ChuAbstract:A new WDM Packet switch architecture, partially shared buffering, is proposed. This architecture, in addition to dedicating an individual prime buffer for each output, incorporates a separate buffer for all the outputs to share. Based on this architecture, a lower Packet Loss Probability can be achieved without the need of either dramatically increasing the size of each prime output buffer or deploying a large number of wavelength converters. The performance of the new architecture has been extensively studied by means of numerical simulations.
V Eramo - One of the best experts on this subject based on the ideXlab platform.
-
cost evaluation of optical Packet switches equipped with limited range and full range converters for contention resolution
Journal of Lightwave Technology, 2008Co-Authors: V Eramo, Marco Listanti, A GermoniAbstract:Two architectures are proposed for a wavelength-division multiplexed optical Packet switch equipped with both limited-range wavelength converters (LRWCs) and shared full-range wavelength converters (FRWCs). The FRWCs are used to overcome the performance degradation in terms of Packet Loss Probability due to the use of LRWCs only. Two different sharing strategies of the FRWCs are considered. In the first architecture, a pool of FRWCs is shared among the arriving Packets. In the second one, the sharing is only partial and the Packets directed to the same output share a same pool of FRWCs. A probabilistic model is proposed to dimension the number of shared FRWCs so that the same Packet Loss Probability of a switch equipped with only shared FRWCs is guaranteed. After introducing a cost model of the converters depending on the conversion range, we show that the architectures may allow a conversion cost savings on the order of 90%.
-
Packet Loss in a bufferless optical wdm switch employing shared tunable wavelength converters
Journal of Lightwave Technology, 2000Co-Authors: V Eramo, Marco ListantiAbstract:We propose an architecture for a bufferless Packet optical switch employing the wavelength dimension for contention resolution. The optical Packet switch is equipped with tunable wavelength converters shared among the input lines. An analytical model Is proposed in order to determine the number of converters needed to satisfy prefixed Packet Loss Probability constraints. This analytical model very accurately fits with simulations results. A sensitivity analysis of the required number of converters as a function of the main system parameters (number of input and output lines, number of wavelengths, ...) and traffic parameters has been carried out. Making use of the introduced dimensioning procedure we have observed that the proposed architecture allows a saving in terms of employed number of converters with respect to the other architectures proposed in literature. Such a saving can reach about 95% of the number of converters.
