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Paolo Zaffoni

Bio: Paolo Zaffoni is an academic researcher from University of Bologna. The author has contributed to research in topics: Transmission delay & Burst switching. The author has an hindex of 8, co-authored 16 publications receiving 178 citations.

Papers
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Journal ArticleDOI
TL;DR: By designing congestion resolution algorithms that combine the use of the wavelength and the time domain it is possible to significantly reduce information loss phenomena and also to guarantee quality of service differentiation among traffic classes by means of QoS algorithms specifically designed to exploit the characteristics of optical technology.

45 citations

Proceedings ArticleDOI
11 Jun 2003
TL;DR: In this paper, a joint comparative performance evaluation of contention resolution in OBS and OPS is presented, as well as methods of quality of service (QoS) differentiation in optical burst switching (OBS) and optical packet switching (OPS).
Abstract: Future network should be able to efficiently serve packet-based networks, such as the Internet. In this paper, based on results from COST 266, we explore characteristics of optical burst switching (OBS) and optical packet switching (OPS). Both node design and metropolitan area network (MAN) are discussed. A unique joint comparative performance evaluation of contention resolution in OBS and OPS are presented, as well as methods of quality of service (QoS) differentiation in OBS/OPS networks, and their performance.

20 citations

Journal ArticleDOI
TL;DR: Simulation results suggest that by accepting some additional processing effort it is possible to guarantee very low packet loss probabilities while avoiding the out-of-sequence delivery.

17 citations

Proceedings ArticleDOI
24 Jun 2003
TL;DR: The paper considers the optical packet assembly process at the ingress router of an optical packet-switched network with the target of end-to-end interconnection of TCP/IP based applications.
Abstract: The paper considers the optical packet assembly process at the ingress router of an optical packet-switched network with the target of end-to-end interconnection of TCP/IP based applications. The architecture and functions of the interworking unit between IP and optical packets are described under the assumption of fixed length optical packets, and also for multiservice transfer. The influence of the main design parameters on end-to-end performance is evaluated using the ns-2 simulator and criteria for the choice of optical packet length and packet assembly time-out are given.

16 citations

Book ChapterDOI
TL;DR: In the paper it is shown that the proposed strategy guarantees very good performance to the high priority traffic with very limited impact on low priority traffic.
Abstract: This paper considers the problem of service differentiation in an optical packet switched backbone. We propose and analyze a QoS routing approach based on different routing and congestion management strategies for different classes of service. Congestion resolution is achieved by using the wavelength and time domain and QoS differentiation in the single node is achieved by resource reservation in the wavelength domain. This is combined with alternate routing at the network level. In the paper we show that the proposed strategy guarantees very good performance to the high priority traffic with very limited impact on low priority traffic.

15 citations


Cited by
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Journal ArticleDOI
TL;DR: The contention resolution and avoidance schemes proposed for bufferless OPS networks are surveyed and the Quality of Service (QoS) issue in a QoS-capable bufferlessOPS network is reviewed.
Abstract: Optical Packet Switching (OPS) is the promising switching technique to utilize the huge bandwidth offered by all-optical networks using the DWDM (Dense Wavelength Division Multiplexing) technology. However, optical packet contention is the major problem in an OPS network. Resolution and avoidance are two schemes to deal with the contention problem. A resolution scheme resolves collisions, while an avoidance scheme tries to reduce the number of potential collision events. Many OPS architectures rely on optical buffers to resolve contention. Unfortunately, optical buffering technology is still immature as it relies on bulky optical fiber delay lines. Furthermore, it requires a complex control. Therefore, a bufferless OPS network could still be the most straightforward implementation in the near future. In this article, we survey the contention resolution and avoidance schemes proposed for bufferless OPS networks. We also review the resolution and avoidance schemes that can handle the Quality of Service (QoS) issue in a QoS-capable bufferless OPS network.

95 citations

Journal ArticleDOI
TL;DR: The architecture is suitable for optical packet and optical burst switching and provides appropriate contention resolution schemes and QoS guarantees and a concept, called virtual memory, is developed to allow controllable and reasonable periods for delaying optical traffics.
Abstract: This paper presents an architecture for an all optical switching node. The architecture is suitable for optical packet and optical burst switching and provides appropriate contention resolution schemes and QoS guarantees. A concept, called virtual memory, is developed to allow controllable and reasonable periods for delaying optical traffics. Related to its implementation, several engineering issues are discussed, including the use of loopbased optical delay lines, fiber Bragg gratings, and limited number of signal amplifications. In particular, two implementations using optical flip-flop and laser neuron network based control units are analyzed. This paper also discusses the implementation and performance of an alloptical synchronizer that is able to synchronize arriving data units to be aligned on the clock signal associated with the beginning time of slots, in the node, with an acceptable error.

27 citations

Journal ArticleDOI
TL;DR: An overview of Quality of Service (QoS) differentiation mechanisms proposed for Optical Burst Switching (OBS) networks is presented and numerical examples on how QoS differentiation with respect to burst loss rate and transport layer throughput can be achieved in OBS networks are provided.

24 citations

Journal ArticleDOI
TL;DR: Among the considered node architectures the highest maximum throughput can be achieved with TAS-LTR due to the smaller number of SOA noise contributions, and the advanced contention resolution functionality leads to smaller-sized nodes due to higher losses and noise.
Abstract: In this paper, we show the physical limitations of semiconductor optical amplifier (SOA)-based switching nodes for optical burst switching (OBS). The investigation covers one basic tune-and-select (TAS) architecture, as well as extensions with wavelength converters of limited tuning range (LTR) and dedicated and shared fiber delay line (FDL) buffers. Their maximum size and throughput are analyzed for nodes with four input/output fibers at different bit rates. As main impairments for signal degradation amplifier noise and crosstalk are considered. It is shown that the advanced contention resolution functionality leads to smaller-sized nodes due to higher losses and noise. Among the considered node architectures the highest maximum throughput can be achieved with TAS-LTR due to the smaller number of SOA noise contributions.

23 citations

Proceedings ArticleDOI
01 Sep 2007
TL;DR: This paper focuses on the key parameters that can be used to design and optimize an optical packet/burst contention resolution scheme and shows how such parameters should be correlated for a correct performance assessment, taking into account feasibility trade-offs due to limited optical buffering and wavelength conversion capability.
Abstract: Optical networking paradigms based on statistical multiplexing, such as Optical Burst Switching or Optical Packet Switching, require the adoption of suitable contention resolution mechanisms at the optical nodes due to packets/bursts attempting to get access to the shared output channel at the same time. In the most general case of multi-fiber output links, contentions are tried to be solved by exploiting different domains — namely space, wavelength and time — and by applying an optimal scheduling policy. This paper focuses on the key parameters that can be used to design and optimize an optical packet/burst contention resolution scheme and shows how such parameters should be correlated for a correct performance assessment, taking into account feasibility trade-offs due to limited optical buffering and wavelength conversion capability.

21 citations