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

MANAGING CONTENTION AVOIDANCE AND MAXIMIZING THROUGHPUT IN OBS NETWORK

Optical Burst Switching (OBS) is a promising technology for future optical networks. Due to its less complicated implementation using current optical and electrical components, OBS is seen as the first step towards the future Optical Packet Switching (OPS). In OBS, a key problem is to schedule bursts on wavelength channels whose bandwidth may become fragmented with the so-called void (or idle) intervals with both fast and bandwidth efficient algorithms so as to reduce burst loss. In this paper, a new scheme has been proposed to improve the throughput and to avoid the contention in the OBS network. The proposed scheme offers the same node complexity as that in general OBS networks with optical buffers. Also, it avoids burst blockings in transit nodes, turning it into an efficient and simple burst contention avoidance mechanism. Simulation results show that the proposed scheme has improvement of 15% in terms of burst loss probability as compared to OBS existing schemes and also maximizes the throughput of the network without deteriorating excessively other parameters such as end to end delay or ingress queues

A zero burst loss architecture for star OBS networks

Performance studies point to the fact that in an OBS network, the link utilization has to be kept very low in order for the burst loss probability to be within an acceptable level. Various congestion control schemes have been proposed, such as the use of converters, fiber delay lines, and deflection routing. However, these schemes do not alleviate this problem. It is our position that in order for OBS to become commercially viable, new schemes have to be devised that will either guarantee zero burst loss, or very low burst loss at high utilization. In a previous paper, we described effective zero burst loss schemes for OBS rings. In this paper, we present a zero burst loss scheme for star OBS topologies. Further research into the topic is required.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

Burst switched optical networks supporting legacy and future service types

Focusing on the principles and the paradigm of OBS an overview addressing expectable performance and application issues is presented. Proposals on OBS were published over a decade and the presented techniques spread into many directions. The paper comprises discussions of several challenges that OBS meets, in order to compile the big picture. The OBS principle is presented unrestricted to individual proposals and trends. Merits are openly discussed, considering basic teletraffic theory and common traffic characterisation. A more generic OBS paradigm than usual is impartially discussed and found capable to overcome shortcomings of recent proposals. In conclusion, an OBS that offers different connection types may support most client demands within a sole optical network layer

Simulation of CPRI traffic on Optical Ethernet

Evolution of mobile networks calls for novel ways of reducing delays while improving the network capacity. All application types require a system to utilize the expanding data. In the future, the projection is that quality of service (QoS) will be a key measurement of any network. Delay and jitter present a challenge to achieving the QoS needed. This is due to the loss of packets experienced during transmission and retransmission. Hence, the thesis proposes a Hybrid switching solution to increase the efficiency of transport networks for mobile data. This is done by designing a model that reduces the number of wavelengths needed to transport Common Public Radio interface (CPRI) over Ethernet while sharing the same optical resources for conventional backhaul traffic. CPRI over Ethernet is an ideal method to aid in better exploitation of the resources. The proposed strategy minimizes the loss of packets by making use of the available gaps during the transmission. Implementing such a model requires a Guaranteed Service Traffic (GST) class, which does not allow for packet loss and is treated as high priority traffic. Additionally, GST has a fixed low delay that makes it resilient to any form of network failures. Moreover, CPRI assists in saving costs by exploiting the unused wavelength capacity left by the GST traffic. Backhaul traffic can exploit this unused capacity to make the system compact. The thesis considers two classes of service levels with possible set of services that have QoS. These are CPRI over Ethernet (CPRIoE) and traditional packet-based Backhaul traffic. CPRIoE is considered as the GST traffic while Backhaul is the Best Effort (BE) traffic. Both traffics are transported over the same links, sharing wavelength resources. The results indicate the effectiveness of combining services in managing multiple flows, thus saving resources and optimizing the network

An improvement over TCP Vegas to enhance its performance in optical burst switching networks

This is a post-peer-review, pre-copyedit version of an article published in Optical review. The final authenticated version is available online at: http://dx.doi.org/10.1007/s10043-021-00652-w.The demand for high bandwidth on the Internet is growing drastically, and one of the solutions for tackling this problem is using optical networks. Burst switching is one of the techniques that can be used in optical networks to handle high traffic. Aside from the many advantages that this technique has, it suffers from a big flaw called burst contention. Optical burst switching (OBS) is a switching technique without any buffering system. As a result, when two bursts are trying to reserve one resource, one of them drops. This drawback can have a significant impact on the performance of some protocols like TCP because they have not been designed to perform in a network without any queuing system and cannot distinguish a drop is because of the congestion or contention. In this paper, a new algorithm called AVGR (Average of RTTs) is proposed based on some mathematical equations to prevent the degradation of TCP. It tries to calculate averages for some RTTs in three different periods. Then base on the obtained results, the congestion control mechanism will be modified. The primary goal of the algorithm is to determine the current status of the network and make proper decisions based on it.This work has been funded by the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya (2017 SGR 376) and the Spanish Government under Project PID2019-106808RA-I00 AEI/FEDER UE.Peer ReviewedPostprint (author's final draft

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

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

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