Algorithms for quality of service provisioning and enhancement in optical burst switched networks

Ph.DDOCTOR OF PHILOSOPH

Trends in optical burst switching

One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modi¯cation of the content of the paper are prohibited

Analytical modeling for the threshold service differentiation mechanism in asynchronous optical buffers

With the emergence of different kinds of applications, service differentiation has become an important issue to be considered in current and future networks. We propose an exact analytical model for evaluating the performance of feed-forward delay-line buffers when the threshold mechanism is used for service differentiation in asynchronous optical packet-switched networks. The analytical model was derived assuming Poisson arrivals and any packet length distribution. Parameters such as buffer size, load, and others do not affect the accuracy of the model. In addition, it can use an arbitrary number of service-differentiated classes and traffic partitioning within them. To check the exactness of the model, we compared the buffer modeling with simulation results when exponential and uniform distributions are considered for the packet length. The analysis presented here shows that by using the threshold mechanism, it is possible to effectively differentiate the per class packet blocking probability. (c) 2007 Optical Society of America.6787188

Modeling and system improvements for wavelength conversion in optical switching nodes

Ph.DDOCTOR OF PHILOSOPH

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

Quality of service in optical burst switching networks

Tese dout., Engenharia Electrónica e Computação, Universidade do Algarve, 2009Fundação para e Ciência e a Tecnologi

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

Multiservice QoS-Enabled MAC for Optical Burst Switching

The emergence of a broad range of network-driven applications (e.g., multimedia, online gaming) brings in the need for a network environment able to provide multiservice capabilities with diverse quality-of-service (QoS) guarantees. In this paper, a medium access control protocol is proposed to support multiple services and QoS levels in optical burst-switched mesh networks without wavelength conversion. The protocol provides two different access mechanisms, queue-arbitrated and prearbitrated for connectionless and connection-oriented burst transport, respectively. It has been evaluated through extensive simulations and its simplistic form makes it very promising for implementation and deployment. Results indicate that the protocol can clearly provide a relative quality differentiation for connectionless traffic and guarantee null (or negligible, and thus acceptable) burst loss probability for a wide range of network (or offered) load while ensuring low access delay for the higher-priority traffic. Furthermore, in the multiservice scenario mixing connectionless and connection-oriented burst transmissions, three different prearbitrated slot scheduling algorithms are evaluated, each one providing a different performance in terms of connection blocking probability. The overall results demonstrate the suitability of this architecture for future integrated multiservice optical networks