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

Improving the optical burst switching networks quality of service by ensuring the fireness among the network traffic types

The Optical burst switching (OBS) networks have been attracting much consideration as a promising approach to build the next generation optical Internet. Aggregating the burst in the OBS networks from the high priority traffic will increase the average of the loss of its packets. However, the ratio of the high priority traffic (e.g. real-time traffic) in the burst is a very important factor for reducing the data loss, and ensuring the fairness between network traffic types. This paper introduces a statistical study based on the significant difference between the traffics to find the fairness ratio for the high priority traffic packets against the low priority traffic packets inside the data burst with various network traffic loads. The results show an improvement in the OBS quality of service (QoS) performance and the high priority traffic packets fairness ratio inside the data burst is 50 to 60%, 30 to 40%, and 10 to 20% for high, normal, and low traffic loads, respectively

Simulation Model for OBS Contention Avoidance Routing Strategies

Abstract. Optical burst switching (OBS) provides a feasible paradigm for the next IP over optical network backbones. However, due to its bufferless nature, OBS efficiency can be reduced by resource contention leading to burst loss. Several methods have been proposed to address this problem, most of them relying on reactive mechanisms which increase the complexity of core nodes, hampering scalability. In this work we consider a preventive traffic engineering approach for contention resolution which provides source routing with the objective of minimizing contention at the transmission links considering only topological information. This paper presents a simulation model aimed at the evaluation of different offline routing strategies in terms of burst contention. The simulation model is used to compare the performance of different novel path selection strategies with the traditional shortest path routing approach. Results confirm that the proposed strategies are effective in reducing the overall blocking and the model is feasible for the proposed QoS evaluation

AVANCES HACIA CONMUTACIÓN Y ENRUTAMIENTO COMPLETAMENTE ÓPTICOS EN REDES TIPO CORE

RESUMEN En la última década Internet ha tenido un crecimiento exponencial en el número de usuarios nuevos haciendo que las expectativas en cuanto a la calidad del servicio recibido sean evaluadas constantemente. Estas y otras exigencias constituyen la problemática principal que se relaciona con el comportamiento y desempeño en la infraestructura de las redes de acceso y tipo core definidas como soporte para las denominadas redes de próxima generación o NGN con orientación “todo IP”, es así como las propuestas en cuanto al soporte óptico desarrolladas hasta el momento, no aseguran que los resultados de su despliegue sean satisfactorios. Las redes ópticas surgen como una de las tecnologías más prometedoras para cubrir la demanda en cuanto a ancho de banda, capacidad de la red, calidad de servicio y desempeño. Lo anterior se soporta en el hecho del gran número de investigaciones que se están llevando a cabo por parte de Universidades, empresas y grupos alrededor del mundo respecto a las telecomunicaciones ópticas. OBS y OPS (conmutación óptica de ráfagas y de paquetes, respectivamente) son los avances con mayor relevancia en la actualidad prometiendo una red tipo core adaptable a los requerimientos de los servicios y a los cambios en la infraestructura de la red. Los avances más recientes en estas tecnologías aseguran un mejor aprovechamiento de la infraestructura óptica existente y por desplegar, asegurando procesos completamente ópticos (conmutación y enrutamiento) con retardos mínimos jamás alcanzados hasta ahora. PALABRAS CLAVES: Redes de Próxima Generación, Conmutación Óptica de Paquetes, Conmutación Óptica de Ráfagas, Calidad de Servicio y Dominio Óptico.  ANALYTICAL SUMMARY In the last decade Internet has experienced an explosive growth due to numbers of new users as well as their expectations to quality of receiving services. These changes are major problem in core networks and the technology used so far does not assure satisfying results. Optical networks have emerged as a promising technology to fulfill growing demands on networks capacity, Quality of Service and performance. Moreover, a wide variety of technologies of fiber communication and networking are focus of research in optical telecommunication domain. Optical Packet/ Burst Switching Network (OPS/OBS) is a promising technology to present and future core networks due to best network utilization and adaptability to changes in the network infrastructure (core network).  KEYWORDS: Next Generation Networks, Optical Packet and Burst Switching, Quality of Service and Optical domain

AVANCES HACIA CONMUTACIÓN Y ENRUTAMIENTO COMPLETAMENTE ÓPTICOS EN REDES TIPO CORE

RESUMEN En la última década Internet ha tenido un crecimiento exponencial en el número de usuarios nuevos haciendo que las expectativas en cuanto a la calidad del servicio recibido sean evaluadas constantemente. Estas y otras exigencias constituyen la problemática principal que se relaciona con el comportamiento y desempeño en la infraestructura de las redes de acceso y tipo core definidas como soporte para las denominadas redes de próxima generación o NGN con orientación “todo IP”, es así como las propuestas en cuanto al soporte óptico desarrolladas hasta el momento, no aseguran que los resultados de su despliegue sean satisfactorios. Las redes ópticas surgen como una de las tecnologías más prometedoras para cubrir la demanda en cuanto a ancho de banda, capacidad de la red, calidad de servicio y desempeño. Lo anterior se soporta en el hecho del gran número de investigaciones que se están llevando a cabo por parte de Universidades, empresas y grupos alrededor del mundo respecto a las telecomunicaciones ópticas. OBS y OPS (conmutación óptica de ráfagas y de paquetes, respectivamente) son los avances con mayor relevancia en la actualidad prometiendo una red tipo core adaptable a los requerimientos de los servicios y a los cambios en la infraestructura de la red. Los avances más recientes en estas tecnologías aseguran un mejor aprovechamiento de la infraestructura óptica existente y por desplegar, asegurando procesos completamente ópticos (conmutación y enrutamiento) con retardos mínimos jamás alcanzados hasta ahora. PALABRAS CLAVES: Redes de Próxima Generación, Conmutación Óptica de Paquetes, Conmutación Óptica de Ráfagas, Calidad de Servicio y Dominio Óptico.  ANALYTICAL SUMMARY In the last decade Internet has experienced an explosive growth due to numbers of new users as well as their expectations to quality of receiving services. These changes are major problem in core networks and the technology used so far does not assure satisfying results. Optical networks have emerged as a promising technology to fulfill growing demands on networks capacity, Quality of Service and performance. Moreover, a wide variety of technologies of fiber communication and networking are focus of research in optical telecommunication domain. Optical Packet/ Burst Switching Network (OPS/OBS) is a promising technology to present and future core networks due to best network utilization and adaptability to changes in the network infrastructure (core network).  KEYWORDS: Next Generation Networks, Optical Packet and Burst Switching, Quality of Service and Optical domain

Performance improvement methods for burst-switched networks

In this paper, we present a performance model of optical burst switching (OBS) that can explain the degradation of OBS throughput performance when the control packet processing time increases. We then use the proposed performance model to investigate three feasible methods to improve OBS performance without significantly increasing the implementation complexity: addition of simple fiber delay lines (FDLs), random extra offset time, and window-based channel scheduling (WBS). Additional FDLs can eliminate the negative impact caused by the variation of the offset time between control packets and data bursts. The random extra offset time approach does not require any additional hardware and computational capability in the nodes. If higher computational capability is available, WBS in general can provide better throughput improvement than that of random extra offset time when FDLs are used in the nodes to compensate the processing time. Simulation results show that a combination of the proposed methods can significantly improve OBS performance. © 2011 Optical Society of America.published_or_final_versio