Exact performance analysis of a single-wavelength optical buffer with correlated inter-arrival times

Providing a photonic alternative to the current electronic switching in the backbone, optical packet switching (OPS) and optical bursts witching (OBS) require optical buffering. Optical buffering exploits delays in long optical fibers; an optical buffer is implemented by routing packets through a set of fiber delay lines (FDLs). Previous studies pointed out that, in comparison with electronic buffers, optical buffering suffers from an additional performance degradation. This contribution builds on this observation by studying optical buffer performance under more general traffic assumptions. Features of the optical buffer model under consideration include a Markovian arrival process, general burst sizes and a finite set of fiber delay lines of arbitrary length. Our algorithmic approach yields instant analytic results for important performance measures such as the burst loss ratio and the mean delay

Cost-based burst dropping strategy in optical burst switching networks

Optical burst switching (OBS) is a new paradigm for future all-optical networks. Intentional burst dropping is one of techniques used to achieve desired quality of service. In this paper we note that some bursts are more likely to cause contention. We propose a cost function that can be used to predict the likelihood that a given burst will interfere with other traffic, then we explain how, by using this information a new burst dropping strategy can be designed. We compare our method with a random burst dropping technique and show that the cost-based approach offers a significant performance improvement

Performance Evaluation of the Labelled OBS Architecture

A comparison of three different Optical Burst Switching (OBS) architectures is made, in terms of performance criteria, control and hardware complexity, fairness, resource utilization, and burst loss probability. Regarding burst losses, we distinguish the losses due to burst contentions from those due to contentions of Burst Control Packets (BCP). The simulation results show that as a counterpart of an its additional hardware complexity, the labelled OBS (L-OBS) is an efficient OBS architecture compared to a Conventional OBS (C-OBS) as well as in comparison with Offset Time-Emulated OBS (E-OBS)

Multi-Granular Optical Cross-Connect: Design, Analysis, and Demonstration

A fundamental issue in all-optical switching is to offer efficient and cost-effective transport services for a wide range of bandwidth granularities. This paper presents multi-granular optical cross-connect (MG-OXC) architectures that combine slow (ms regime) and fast (ns regime) switch elements, in order to support optical circuit switching (OCS), optical burst switching (OBS), and even optical packet switching (OPS). The MG-OXC architectures are designed to provide a cost-effective approach, while offering the flexibility and reconfigurability to deal with dynamic requirements of different applications. All proposed MG-OXC designs are analyzed and compared in terms of dimensionality, flexibility/reconfigurability, and scalability. Furthermore, node level simulations are conducted to evaluate the performance of MG-OXCs under different traffic regimes. Finally, the feasibility of the proposed architectures is demonstrated on an application-aware, multi-bit-rate (10 and 40 Gbps), end-to-end OBS testbed

Novel resource reservation schemes for optical burst switching

We propose to improve the throughput performance of optical burst switching by using regional controller nodes and window-based reservation. Both methods increase the information available to the intermediate nodes during scheduling decisions. Simulations show that the proposed reservation schemes provide significant improvement in the throughput performance compared with the original optical burst switching when the network is heavily loaded. © 2005 IEEE.published_or_final_versio

Cost functions in optical burst-switched networks

Optical Burst Switching (OBS) is a new paradigm for an all-optical Internet. It combines the best features of Optical Circuit Switching (OCS) and Optical Packet Switching (OPS) while avoidmg the mam problems associated with those networks .Namely, it offers good granularity, but its hardware requirements are lower than those of OPS. In a backbone network, low loss ratio is of particular importance. Also, to meet varying user requirements, it should support multiple classes of service. In Optical Burst-Switched networks both these goals are closely related to the way bursts are arranged in channels. Unlike the case of circuit switching, scheduling decisions affect the loss probability of future burst This thesis proposes the idea of a cost function. The cost function is used to judge the quality of a burst arrangement and estimate the probability that this burst will interfere with future bursts. Two applications of the cost functio n are proposed. A scheduling algorithm uses the value of the cost function to optimize the alignment of the new burst with other bursts in a channel, thus minimising the loss ratio. A cost-based burst droppmg algorithm, that can be used as a part of a Quality of Service scheme, drops only those bursts, for which the cost function value indicates that are most likely to cause a contention. Simulation results, performed using a custom-made OBS extension to the ns-2 simulator, show that the cost-based algorithms improve network performanc

Performance assessment of optical packet switching system with burst-mode receivers for intra-data centre networks

We investigate the performance of a burst-mode receiver in an optical packet switching system. Experimental results indicate that a preamble of 25.6ns allows error-free operation of 10Gb/s asynchronous switched packets with 8dB dynamic range and 25ns minimum guard-time

125 Gbit/s discretely tunable InP-on-silicon filtered feedback laser with sub-nanosecond wavelength switching times

A heterogeneously integrated InP-on-silicon fast tunable filtered feedback laser is demonstrated. The laser device consists of a main Fabry-Pérot cavity connected to an integrated arrayed waveguide grating of which the outputs form external cavities in which semiconductor optical amplifiers can be switched to provide single-mode operation and tunability. The laser can operate at four different wavelengths whereby switching between each wavelength channel is done within one nanosecond. For each wavelength channel 12.5 Gbit/s NRZ-OOK direct modulation is demonstrated. The combination of fast wavelength switching with straightforward wavelength control and high-speed direct modulation characteristics make the demonstrated laser structure very attractive for use in optical packet or burst switching systems

Time-Synchronized Optical Burst Switching

Optical Burst Switching was recently introduced as a protocol for the next generation optical Wavelength Division Multiplexing (WDM) network. Currently, in legacy Optical Circuit Switching over the WDM network, the highest bandwidth utilization cannot be achieved over the network. Because of its physical complexities and many technical obstacles, the lack of an optical buffer and the inefficiency of optical processing, Optical Packet Switching is difficult to implement. Optical Burst Switching (OBS) is introduced as a compromised solution between Optical Circuit Switching and Optical Packet Switching. It is designed to solve the problems and support the unique characteristics of an optical-based network. Since OBS works based on all-optical switching techniques, two major challenges in designing an effective OBS system have to be taken in consideration. One of the challenges is the cost and complexities of implementation, and another is the performance of the system in terms of blocking probabilities. This research proposes a variation of Optical Burst Switching called Time-Synchronized Optical Burst Switching. Time-Synchronized Optical Burst Switching employs a synchronized timeslot-based mechanism that allows a less complex physical switching fabric to be implemented, as well as to provide an opportunity to achieve better resource utilization in the network compared to the traditional Optical Burst Switching