A Novel QoS provisioning Scheme for OBS networks

This paper presents Classified Cloning, a novel QoS provisioning mechanism for OBS networks carrying real-time applications (such as video on demand, Voice over IP, online gaming and Grid computing). It provides such applications with a minimum loss rate while minimizing end-to-end delay and jitter. ns-2 has been used as the simulation tool, with new OBS modules having been developed for performance evaluation purposes. Ingress node performance has been investigated, as well as the overall performance of the suggested scheme. The results obtained showed that new scheme has superior performance to classical cloning. In particular, QoS provisioning offers a guaranteed burst loss rate, delay and expected value of jitter, unlike existing proposals for QoS implementation in OBS which use the burst offset time to provide such differentiation. Indeed, classical schemes increase both end-to-end delay and jitter. It is shown that the burst loss rate is reduced by 50% reduced over classical cloning

A novel ingress node design for video streaming over optical burst switching networks

This paper introduces a novel ingress node design which takes advantage of video data partitioning in order to deliver enhanced video streaming quality when using H.264/AVC codec over optical burst switching networks. Ns2 simulations show that the proposed scheme delivers improved video traffic quality without affecting other traffic, such as best effort traffic. Although the extra network load is comparatively small, the average gain in video PSNR was 5 dB over existing burst cloning schemes, with a maximum end-to-end delay of 17 ms, and jitter of less than 0.35 ms

Design And Analysis Of Effective Routing And Channel Scheduling For Wavelength Division Multiplexing Optical Networks

Optical networking, employing wavelength division multiplexing (WDM), is seen as the technology of the future for the Internet. This dissertation investigates several important problems affecting optical circuit switching (OCS) and optical burst switching (OBS) networks. Novel algorithms and new approaches to improve the performance of these networks through effective routing and channel scheduling are presented. Extensive simulations and analytical modeling have both been used to evaluate the effectiveness of the proposed algorithms in achieving lower blocking probability, better fairness as well as faster switching. The simulation tests were performed over a variety of optical network topologies including the ring and mesh topologies, the U.S. Long-Haul topology, the Abilene high-speed optical network used in Internet 2, the Toronto Metropolitan topology and the European Optical topology. Optical routing protocols previously published in the literature have largely ignored the noise and timing jitter accumulation caused by cascading several wavelength conversions along the lightpath of the data burst. This dissertation has identified and evaluated a new constraint, called the wavelength conversion cascading constraint. According to this constraint, the deployment of wavelength converters in future optical networks will be constrained by a bound on the number of wavelength conversions that a signal can go through when it is switched all-optically from the source to the destination. Extensive simulation results have conclusively demonstrated that the presence of this constraint causes significant performance deterioration in existing routing and wavelength assignment (RWA) algorithms. Higher blocking probability and/or worse fairness have been observed for existing RWA algorithms when the cascading constraint is not ignored. To counteract the negative side effect of the cascading constraint, two constraint-aware routing algorithms are proposed for OCS networks: the desirable greedy algorithm and the weighted adaptive algorithm. The two algorithms perform source routing using link connectivity and the global state information of each wavelength. Extensive comparative simulation results have illustrated that by limiting the negative cascading impact to the minimum extent practicable, the proposed approaches can dramatically decrease the blocking probability for a variety of optical network topologies. The dissertation has developed a suite of three fairness-improving adaptive routing algorithms in OBS networks. The adaptive routing schemes consider the transient link congestion at the moment when bursts arrive and use this information to reduce the overall burst loss probability. The proposed schemes also resolve the intrinsic unfairness defect of existing popular signaling protocols. The extensive simulation results have shown that the proposed schemes generally outperform the popular shortest path routing algorithm and the improvement could be substantial. A two-dimensional Markov chain analytical model has also been developed and used to analyze the burst loss probabilities for symmetrical ring networks. The accuracy of the model has been validated by simulation. Effective proactive routing and preemptive channel scheduling have also been proposed to address the conversion cascading constraint in OBS environments. The proactive routing adapts the fairness-improving adaptive routing mentioned earlier to the environment of cascaded wavelength conversions. On the other hand, the preemptive channel scheduling approach uses a dynamic priority for each burst based on the constraint threshold and the current number of performed wavelength conversions. Empirical results have proved that when the cascading constraint is present, both approaches would not only decrease the burst loss rates greatly, but also improve the transmission fairness among bursts with different hop counts to a large extent

MANAGING CONTENTION AVOIDANCE AND MAXIMIZING THROUGHPUT IN OBS NETWORK

Optical Burst Switching (OBS) is a promising technology for future optical networks. Due to its less complicated implementation using current optical and electrical components, OBS is seen as the first step towards the future Optical Packet Switching (OPS). In OBS, a key problem is to schedule bursts on wavelength channels whose bandwidth may become fragmented with the so-called void (or idle) intervals with both fast and bandwidth efficient algorithms so as to reduce burst loss. In this paper, a new scheme has been proposed to improve the throughput and to avoid the contention in the OBS network. The proposed scheme offers the same node complexity as that in general OBS networks with optical buffers. Also, it avoids burst blockings in transit nodes, turning it into an efficient and simple burst contention avoidance mechanism. Simulation results show that the proposed scheme has improvement of 15% in terms of burst loss probability as compared to OBS existing schemes and also maximizes the throughput of the network without deteriorating excessively other parameters such as end to end delay or ingress queues

Deflection Routing Strategies for Optical Burst Switching Networks: Contemporary Affirmation of the Recent Literature

A promising option to raising busty interchange in system communication could be Optical Burst Switched (OBS) networks among scalable and support routing effective. The routing schemes with disputation resolution got much interest, because the OBS network is buffer less in character. Because the deflection steering can use limited optical buffering or actually no buffering thus the choice or deflection routing techniques can be critical. Within this paper we investigate the affirmation of the current literature on alternate (deflection) routing strategies accessible for OBS networks

A performance survey on deflection routing techniques for OBS networks

In this paper, we present a survey comparing different deflection routing based techniques applied to optical burst switching (OBS) networks. For such study we consider the E-OBS architecture proposed in [1] which is an advantageous solution for OBS networks since routing decision can be taken freely inside the network without constraints on the length of the path. Under this environment, several effective routing strategies proposed in the literature are applied, namely deflection routing, reflection routing, reflection-deflection routing and multitopology routing. The aim of this study is to analyse all these techniques considering both asynchronous and synchronous burst arrivals and compare their benefits. Moreover, we focus on a quasi-synchronous burst arrival case (with bursts not perfectly aligned) and analyse the trade-off between performance and alignment.Peer ReviewedPostprint (published version

Burst contention avoidance schemes in hybrid GMPLS-enabled OBS/OCS optical networks

Hybrid optical network architectures, combining benefits of optical circuit and burst switching technologies, become a natural evolution to improve overall network performance while reducing related costs. This paper concentrates on preventive contention avoidance schemes to decrease burst loss probability at the OBS layer of such hybrid network scenarios. Into operation, the proposed solution locally reacts to highly loaded downstream node situations by preventively deflecting bursts through a less loaded neighbor. Two different approaches for disseminating adjacent nodes state information are presented and extensively evaluated. In the first approach, current node state information is propagated downstream in the burst control packet, keeping pace with OBS traffic dynamics. The second approach targets at lower control overhead. In this case, averaged node state statistics are included in the Hello messages of the GMPLS Link Management Protocol (LMP) protocol, which are exchanged between neighboring nodes over the OCS control layer every 150 ms. The obtained results validate the applicability of both approaches. Moreover, they indicate that, depending on the mean burst size, either one or the other approach is favorable.Postprint (published version

Performance issues in optical burst/packet switching

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-01524-3_8This chapter summarises the activities on optical packet switching (OPS) and optical burst switching (OBS) carried out by the COST 291 partners in the last 4 years. It consists of an introduction, five sections with contributions on five different specific topics, and a final section dedicated to the conclusions. Each section contains an introductive state-of-the-art description of the specific topic and at least one contribution on that topic. The conclusions give some points on the current situation of the OPS/OBS paradigms

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