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)

A framework for Deterministic Delay Guarantee in OBS Networks

In OBS networks, the delay of control packets in the switch control unit (SCU) of core nodes influences burst loss performance in the optical switching and should be constrained. Furthermore, the end-to-end (E2E) delay requirements of premium services need queueing delay guarantee in network nodes throughout the transmission path. For this purpose, a framework for deterministic delay guarantee is proposed in this article. It incorporates the deterministic delay model in the ingress edge node as well as in the SCUs of core nodes. On this basis, the configuration of the assembler and the offset time is addressed by means of an optimization problem under the delay constraints. Scenario studies are carried out with reference to realistic transport network topologies. Compared to statistical delay models in the literature, the deterministic model has advantages in rendering robust absolute delay guarantee for individual FEC flows, which is especially appreciated in the provisioning of premium services. By performance evaluation in comparison with the statistical models, it is shown that the adopted deterministic delay models lead to practical delay bounds in a magnitude that is close to the delay estimations by stochastic analysis

On IP over WDM burst-switched long haul and metropolitan area networks

The IP over Wavelength Division Multiplexing (WDM) network is a natural evolution ushered in by the phenomenal advances in networking technologies and technical breakthroughs in optical communications, fueled by the increasing demand in the reduction of operation costs and the network management complexity. The unprecedented bandwidth provisioning capability and the multi-service supportability of the WDM technology, in synergy with the data-oriented internetworking mechanisms, facilitates a common shared infrastructure for the Next Generation Internet (NGJ). While NGI targets to perform packet processing directly on the optical transport layer, a smooth evolution is critical to success. Intense research has been conducted to design the new generation optical networks that retain the advantages of packet-oriented transport prototypes while rendering elastic network resource utilization and graded levels of service. This dissertation is focused on the control architecture, enabling technologies, and performance analysis of the WDM burst-switched long haul and Metropolitan Area Networks (MANs). Theoretical analysis and simulation results are reported to demonstrate the system performance and efficiency of proposed algorithms. A novel transmission mechanism, namely, the Forward Resource Reservation (ERR) mechanism, is proposed to reduce the end-to-end delay for an Optical Burst Switching (OBS)-based IP over WDM system. The ERR scheme adopts a Linear Predictive Filter and an aggressive reservation strategy for data burst length prediction and resource reservation, respectively, and is extended to facilitate Quality of Service (QoS) differentiation at network edges. The ERR scheme improves the real-time communication services for applications with time constraints without deleterious system costs. The aggressive strategy for channel holding time reservations is proposed. Specifically, two algorithms, the success probability-driven (SPD) and the bandwidth usage-driven (BUD) ones, are proposed for resource reservations in the FRRenabled scheme. These algorithms render explicit control on the latency reduction improvement and bandwidth usage efficiency, respectively, both of which are important figures of performance metrics. The optimization issue for the FRR-enabled system is studied based on two disciplines - addressing the static and dynamic models targeting different desired objectives (in terms of algorithm efficiency and system performance), and developing a \u27\u27crank back\u27\u27 based signaling mechanism to provide bandwidth usage efficiency. The proposed mechanisms enable the network nodes to make intelligent usage of the bandwidth resources. In addition, a new control architecture with enhanced address resolution protocol (E-ARP), burst-based transmission, and hop-based wavelength allocation is proposed for Ethernet-supported IP over WDM MANs. It is verified, via theoretical analysis and simulation results, that the E-ARP significantly reduces the call setup latency and the transmission requirements associated with the address probing procedures; the burst-based transport mechanism improves the network throughput and resource utilization; and the hop-based wavelength allocation algorithm provides bandwidth multiplexing with fairness and high scalability. The enhancement of the Ethernet services, in tandem with the innovative mechanisms in the WDM domain, facilitates a flexible and efficient integration, thus making the new generation optical MAN optimized for the scalable, survivable, and IP-dominated network at gigabit speed possible

An assembly and offset assignment scheme for self-similar traffic in optical burst switching

Includes bibliographical references.Optical Burst Switching (OBS) is a viable technology for the next generation core network. We propose an FEC-assembly scheme that efficiently assembles self-similar traffic and a Pareto-offset assignment rather than a constant offset assignment. Two buffers, a packet buffer and a burst buffer, are implemented at the Label Edge Router (LER), buffering traffic in the electronic domain. The assembler, between the packet and burst buffers, is served by the packet queue while the assembler serves the burst queue. We outline advantages of why burst assembly cannot be implemented independent of offset assignment. The two schemes must be implemented in a complementary way if QoS is to be realized in an OBS network. We show that there is a direct relation between OBS network performance with burst assembly and offset assignment. We present simulation results of the assembly and offset assignment proposals using the ns2 network simulator. Our results show that the combination of the proposed FEC-Based assembly scheme with the proposed Pareto-offset assignment scheme give better network performance in terms of burst drop, resource contention and delay. Key to any traffic shaping is the nature traffic being shaped. This work also compares performance of both traditional exponential traffic with realistic Self-Similar traffic of Internet traffic on the proposed assembly and offset assignment schemes. In our simulations, we assume that all Label Switch Routers (LSR) have wavelength converters and are without optical buffers. We use Latest Available Unused Channel with Void Filling (LAUC-VF) scheduling scheme and use Just Enough Time (JET) reservation scheme

Performance and cost analysis of all-optical switching: OBS and OCS

This paper presents a study of performance and cost analysis of optical circuit switching (OCS) and optical burstswitching (OBS) by proposing the clear images of their node architectures and cost formulations. Then, we apply servicelevel agreement (SLA) of the high quality of service application in the terms of network blocking probability and averagenetwork delay to demonstrate OCS and OBS performances, their investment costs, and network dimensioning methodology.Applying SLA to our studies can illustrate the impact of contention resolution and blocking resolution schemes to theperformances and costs of OBS and OCS, accordingly. The simulations illustrate that OBS applying WC gives the bestperformance among all architectures deploying the same offered bandwidth. The investigations also show that WC is a majortechnique contributing high performance gain to both OCS and OBS. Especially for OBS, WC is an important scheme allowingOBS high data grooming property as its performance gain contributing to OBS is much higher than those of OCS. For thecost analysis, OCS is the most economic among all architectures. BA provides the most cost effectiveness among all OBScontention resolution schemes. Lastly, FDL is the least cost effective scheme as it gives little performance enhancement butadds more cost to the network

On the benefits of optical gain-clamped amplification in optical burst switching networks

This paper investigates the performance of an all-optical method for amplification gain control to be applied in the next generation of optical networks. An erbium-doped fiber amplifier is implemented in a simple and passive all-optical configuration known as optical gain-clamped optical amplifier (OA). The paper investigates the dynamic performance of the OA and discusses the interplay of amplifier dynamics with different traffic statistics. The investigation concerns exhaustive characterization of bit error rate performances under typical optical burst switching (OBS) traffic as well as special case of sudden power variation at the amplifier input. All obtained results show a reduction in the amplifier output power overshot compared to the case where the same OA operates without any gain stabilization technique. As an example, in the typical OBS traffic scenario, a reduction of 3 dB is observed.Postprint (published version

PI-OBS: a Parallel Iterative Optical Burst Scheduler for OBS networks

This paper presents the PI-OBS algorithm, a parallel-iterative scheduler for OBS nodes. Conventional schemes are greedy in the sense that they process headers one by one. In PI-OBS, all the headers received during a given time window are jointly processed to optimize the delay and output wavelength allocation, applying void filling techniques, and allowing traffic differentiation. Results show a similar or better performance than the LAUC-VF algorithm, commonly used as a performance bound for OBS schedulers. The PI-OBS scheduler has been designed to allow parallel electronic implementation similar to the ones in VOQ schedulers, with a deterministic response time.This research has been partially supported by the MEC projects TEC2007-67966-01/TCM CON-PARTE-1, and TEC2008-02552-E, and it is also developed in the framework of "Programa de Ayudas a Grupos de Excelencia de la R. de Murcia, F. Séneca"

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