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

Equivalent random analysis of a buffered optical switch with general interarrival times

We propose an approximate analytic model of an optical switch with fibre delay lines and wavelength converters by employing Equivalent Random Theory. General arrival traffic is modelled by means of Gamma-distributed interarrival times. The analysis is formulated in terms of virtual traffic flows within the optical switch from which we derive expressions for burst blocking probability, fibre delay line occupancy and mean delay. Emphasis is on approximations that give good numerical efficiency so that the method can be useful for formulating dimensioning problems for large-scale networks. Numerical solution values from the proposed analysis method compare well with results from a discrete-event simulation of an optical burst switch

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

A Unified End-to-End Communication Paradigm for Heterogeneous Networks

The aim of this thesis research is to develop a unified communication paradigm that provides an end-to-end bursting model across heterogeneous realms. This model generates end-to-end bursts, thereby eliminating edge node burst assembly and its effect on TCP performance. Simulation models are developed in ns-2 to validate this work by comparing it with edge burst assembly on OBS networks. Analysis shows improved end-to-end performance for a variety of burst sizes, timeouts, and other network parameters

A new adaptive burst assembly algorithm for OBS networks considering capacity of control plane

Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 2008.Thesis (Master's) -- Bilkent University, 2008.Includes bibliographical references leaves 55-57.Recent developments in wavelength-division multiplexing (WDM) technology increase the amount of bandwidth available in fiber links by many orders of magnitude. However, this increase in link capacities is limited by the conventional electronic router’s capability. Optical burst switching (OBS) has been proposed as a promising and a short-term solution for switching technology to take advantage of increased capacity of optical links. The congestion in OBS control plane and the adaptive burst assembly algorithms are two important research topics that are among the most effective factors determining the performance of OBS networks. These two problems have been separately studied in the literature so far. It has been shown that contending bursts at a core optical switch in an OBS network may experience unfair loss rates based on their residual off- set times and burst lengths, that are called path length priority effect (PLPE) and burst length priority effect (BLPE), respectively. In this thesis, we propose a new adaptive timer-based burst assembly algorithm (ATBA) which uses loss rate measurements for determining the burstification delays of traffic streams in order to mitigate the undesired effects of PLPE and BLPE. ATBA distributes the burst generation rates of traffic streams at an ingress node such that total rate of generated bursts is constant in order to constrain the congestion in the control plane. Without ATBA, the fairness index drops to 76% when per hop processing delay (PHPD) is increasing. With ATBA, the fairness index drops only to 85% with increasing PHPD. It is also shown that the total goodput of the OBS network improves by 5% compared with the case without ATBA.Çırak, İsmailM.S

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

Network level performance of differentiated services (diffserv) networks

The Differentiated Services (DiffServ) architecture is a promising means of providing Quality of Service (QoS) in Internet. In DiffServ networks, three service classes, or Per-hop Behaviors (PHBs), have been defined: Expedited Forwarding (EF), Assured Forwarding (AF) and Best Effort (BE). In this dissertation, the performance of DiffServ networks at the network level, such as end-to-end QoS, network stability, and fairness of bandwidth allocation over the entire network have been extensively investigated. It has been shown in literature that the end-to-end delay of EF traffic can go to infinity even in an over-provisioned network. In this dissertation, a simple scalable aggregate scheduling scheme, called Youngest Serve First (YSF) algorithm is proposed. YSF is not only able to guarantee finite end-to-end delay, but also to keep a low scheduling complexity. With respect to the Best Effort traffic, Random Exponential Marking (REM), an existing AQM scheme is studied under a new continuous time model, and its local stable condition is presented. Next, a novel virtual queue and rate based AQM scheme (VQR) is proposed, and its local stability condition has been presented. Then, a new AQM framework, Edge-based AQM (EAQM) is proposed. EAQM is easier to implement, and it achieves similar or better performance than traditional AQM schemes. With respect to the Assured Forwarding, a network-assist packet marking (NPM) scheme has been proposed. It has been demonstrated that NPM can fairly distribute bandwidth among AF aggregates based on their Committed Information Rates (CIRs) in both single and multiple bottleneck link networks

Analysis of IP delay variation in edge OBS nodes

This is an electronic version of the paper presented at the European Conference on Networks and Optical Communications, held in Stockholm on 2007This paper evaluates the packet delay from its arrival at the burstifier until the burst is finally released. Such evaluation comprises the delay due to burstification together with the delay which is due to waiting in the transmission queue. More specifically, we focus on the delay jitter, which has an impact on the performance of multimedia applications.The authors would like to acknowledge the support of the E-Photon/One+ Network of Excellence (FP6-IST-027497) to this work

Traffic and performance evaluation for optical networks. An Investigation into Modelling and Characterisation of Traffic Flows and Performance Analysis and Engineering for Optical Network Architectures.

The convergence of multiservice heterogeneous networks and ever increasing Internet applications, like peer to peer networking and the increased number of users and services, demand a more efficient bandwidth allocation in optical networks. In this context, new architectures and protocols are needed in conjuction with cost effective quantitative methodologies in order to provide an insight into the performance aspects of the next and future generation Internets. This thesis reports an investigation, based on efficient simulation methodologies, in order to assess existing high performance algorithms and to propose new ones. The analysis of the traffic characteristics of an OC-192 link (9953.28 Mbps) is initially conducted, a requirement due to the discovery of self-similar long-range dependent properties in network traffic, and the suitability of the GE distribution for modelling interarrival times of bursty traffic in short time scales is presented. Consequently, using a heuristic approach, the self-similar properties of the GE/G/¿ are being presented, providing a method to generate self-similar traffic that takes into consideration burstiness in small time scales. A description of the state of the art in optical networking providing a deeper insight into the current technologies, protocols and architectures in the field, which creates the motivation for more research into the promising switching technique of ¿Optical Burst Switching¿ (OBS). An investigation into the performance impact of various burst assembly strategies on an OBS edge node¿s mean buffer length is conducted. Realistic traffic characteristics are considered based on the analysis of the OC-192 backbone traffic traces. In addition the effect of burstiness in the small time scales on mean assembly time and burst size distribution is investigated. A new Dynamic OBS Offset Allocation Protocol is devised and favourable comparisons are carried out between the proposed OBS protocol and the Just Enough Time (JET) protocol, in terms of mean queue length, blocking and throughput. Finally the research focuses on simulation methodologies employed throughout the thesis using the Graphics Processing Unit (GPU) on a commercial NVidia GeForce 8800 GTX, which was initially designed for gaming computers. Parallel generators of Optical Bursts are implemented and simulated in ¿Compute Unified Device Architecture¿ (CUDA) and compared with simulations run on general-purpose CPU proving the GPU to be a cost-effective platform which can significantly speed-up calculations in order to make simulations of more complex and demanding networks easier to develop

Resource reservation protocols for optical burst switched networks

Nesta disserta c~ao e feito um estudo em redes com comuta c~ao optica de agregados de pacotes (redes OBS). Assim, este estudo apresenta e descreve os conceitos mais importantes relacionados com as redes OBS. Inicialmente e analisado o estado da arte, efectuando uma descri c~ao detalhada da arquitectura de uma rede OBS. Seguidamente analisam-se os protocolos de reserva unidireccional de recursos (JIT, JIT+, JET, Jumpstart, Horizon and E-JIT). Para isso s~ao utilizadas redes com topologias regulares (em anel e em malha) com um n umero vari avel de n os, e tamb em irregulares (NSFNET e ARPANET). E tamb em apresentado um novo protocolo de reserva unidireccional de recursos chamado E-JIT+. Este novo protocolo baseia-se no protocolo j a existente JIT+ e tenta optimizar o seu desempenho. Para melhor descrever o modo de opera c~ao deste protocolo proposto e apresentada a especi ca c~ao formal do mesmo. Depois da apresenta c~ao deste protocolo analisa-se o seu desempenho. Para isso s~ao utilizadas as topologias de rede referidas anteriormente e tamb em um simulador de redes OBS adaptado de forma a suportar o novo protocolo. O simulador utilizado, de nome OBSSimulator, devolve os valores de probabilidade de perda dos agregados de pacotes em cada salto (hop) na rede. Deste modo, foram considerados v arios factores que podem in uenciar o desempenho dos protocolos de reserva unidireccional de recursos, tais como o n umero de n os da topologia de rede utilizada, a quantidade de tr afego na rede, o ganho do grau nodal, o tempo de processamento das mensagens de setup e o tempo de con gura c~ao dos comutadores opticos. No m deste trabalho concluiu-se que o protocolo proposto, E-JIT+, melhora o desempenho em rela c~ao aos outros protocolos de reserva unidireccional de recursos estudados, nos casos estudados