QoS Considerations in OBS Switched Backbone Net-Works

Optical Burst Switching (OBS) was proposed as a hybrid switching technology solution to handle the multi-Terabit volumes of traffic anticipated to traverse Future Generation backbone Networks. With OBS, incoming data packets are assembled into super-sized packets called data bursts and then assigned an end to end light path. Key challenging areas with regards to OBS Networks implementation are data bursts assembling and scheduling at the network ingress and core nodes respectively as they are key to minimizing subsequent losses due to contention among themselves in the core nodes. These losses are significant contributories to serious degradation in renderable QoS. The paper overviews existing methods of enhancing it at both burst and transport levels. A distributed resources control architecture is proposed together with a proposed wavelength assignment algorithm

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

A Priority Based Optical Header Contention Resolution in Optical Burst Switching Networks

OBS is a promising switching paradigm for the next-generation Internet.In OBS, data packets are assembled into variable size data burst which are transmitted optically over Dense Wavelength Division Multiplexing(DWDM)networks without O/E/O conversion. The control packet is sent before the data burst to reserve resources and configure switches along the path .The control packet is sent along the separate control channel and goes through O/E/O conversion. We have discussed various OBS signalling protocols and Burst Scheduling Algorithms. As the data channel bandwidth will grow it will lead to the overloading of the control path. In this thesis we have proposed an algorithm to resolve the contention of the optical header. The algorithm assigns the priority to each control packet arriving at the same time .The control packet with highest priority is selected for processing. Simulation results have shown that the technique is effective in improving the throughput

Effective burst preemption in OBS network

Trabajo presentado al Workshop on High Performance Switching and Routing 2006, Poznan (Polonia), 7-9 de junio de 2006Burst preemption is the most effective technique to provide Quality of Service (QoS) differentiation in Optical Burst Switching (OBS) networks. Nonetheless, in conventional OBS architectures, when preemption happens the control packet corresponding to the preempted burst continues its travel to the destination node reserving resources at each node of the path. Therefore, an additional signaling procedure should be carried out to release these unnecessary reservations. In this paper we present novel control architecture to efficiently apply burst preemption without the need of the signaling procedure. Analytical and simulation results prove the effectiveness of this proposal.This work has been partially funded by the e-Photon/ONe project (IST FP6-001933) and the MEC (Spanish Ministry of Education) under contract TEC2005-08051-C03-01

JA(G)OBS Simulator: Implementation of the main features of the routing protocol

Projecte final de carrera fet en col.laboració amb Instituto Universitário de Lisboa. Departamento de Ciências e Tecnologias da InformaçãoEnglish: Optical Burst Switching (OBS) is an optical switching paradigm that has been re-gaining attention in the last few years after its boom around the year 2000. This paradigm is able to bring together the present technology (avoiding the optical buffer technology hurdles) and what is envisaged for future networks (packet-based optical switching). However it lacks a well-defined control plane that can keep up with quality of service (QoS) demands by Internet applications and end-to-end connectivity among multiple switching domains controlled by a single control instance. Generalized Multi-Protocol Layer Switching (GMPLS) is a technology that can give the missing link to OBS. It is the extension of the Multi-Protocol Layer Switching (MPLS) which was designed for IP networks to introduce fast forwarding and Traffic Engineering (TE). GMPLS evolves from MPLS to deal with non-IP networks, e.g. SDH and WDM. However, it does not handle OBS so far. This Master Thesis contributes towards this GMPLS-OBS interoperability by the development of some features to the Java Event-Driven Simulator of the GMPLS-OBS architecture called JA(G)OBS. This thesis comes up in sequence of another UPC-ISCTE Master Thesis of João Baião from September 2010, who implemented some of the basic features of the GMPLS Signaling protocol in the simulator. In particular, this Master Thesis will focus on the implementation of the GMPLS Routing protocol basic features in the simulator and to deploy a Graphical User Interface (GUI) for the simulator. The GMPLS Routing protocol considered in the simulator is the Open Shortest Path First with Traffic Engineering (OSPF-TE) which is one of the standards of GMPLS routing

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)

Joint path and resource selection for OBS grids with adaptive offset based QOS mechanism

Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 2007.Thesis (Master's) -- Bilkent University, 2007.Includes bibliographical references leaves 71-76It is predicted that grid computing will be available for consumers performing their daily computational needs with the deployment of high bandwidth optical networks. Optical burst switching is a suitable switching technology for this kind of consumer grid networks because of its bandwidth granularity. However, high loss rates inherent in OBS has to be addressed to establish a reliable transmission infrastructure. In this thesis, we propose mechanisms to reduce loss rates in an OBS grid scenario by using network-aware resource selection and adaptive offset determination. We first propose a congestion-based joint resource and path selection algorithm. We show that path switching and network-aware resource selection can reduce burst loss probability and average completion time of grid jobs compared to the algorithms that are separately selecting paths and grid resources. In addition to joint resource and path selection, we present an adaptive offset algorithm for grid bursts which minimizes the average completion time. We show that the adaptive offset based QoS mechanism significantly reduces the job completion times by exploiting the trade-off between decreasing loss probability and increasing delay as a result of the extra offset time.Köseoğlu, MehmetM.S