Computers

Optical Burst Switched Networks

Author: Jason P. Jue

Publisher: Springer Science & Business Media

ISBN:

Category: Computers

Page: 147

View: 610

Next-generation high-speed Internet backbone networks will be required to support a broad range of emerging applications which may not only require significant bandwidth, but may also have strict quality of service (QoS) requirements. Furthermore, the traffic from such applications are expected to be highly bursty in nature. For such traffic, the allocation of static fixed-bandwidth circuits may lead to the over-provisioning of bandwidth resources in order to meet QoS requirements. Optical burst switching (OBS) is a promising new technique which attempts to address the problem of efficiently allocating resources for bursty traffic. In OBS, incoming data is assembled into bursts at the edges of the network, and when the burst is ready to be sent, resources in the network are reserved only for the duration of the burst. The reservation of resources is typically made by an out-of-band one-way control message which precedes the burst by some offset time. By reserving resources only for the duration of the burst, a greater degree of utilization may be achieved in the network. This book provides an overview of optical burst switching. Design and research issues involved in the development of OBS networks are discussed, and approaches to providing QoS in OBS networks are presented. Topics include: - Optical burst switching node and network architectures - Burst assembly - Signaling protocols - Contention resolution - Burst scheduling - Quality of service in OBS networks
Technology & Engineering

Quality of Service in Optical Burst Switched Networks

Author: Kee Chaing Chua

Publisher: Springer Science & Business Media

ISBN:

Category: Technology & Engineering

Page: 198

View: 281

Optical Burst Switching (OBS) offers a promising switching technique to support huge bandwidth requirements in optical backbone networks that use Wavelength Division Multiplexing. This book details the quality of service (QoS) issue in OBS networks. It examines the basic mechanisms to improve overall QoS in OBS networks as well as discusses the relative QoS differentiation among multiple service classes in OBS networks. Coverage also details absolute QoS provisioning in OBS networks, end-to-end QoS provisioning in OBS networks, and some non-mainstream research issues and future research directions in OBS networks.
Technology & Engineering

An Analytical Approach to Optical Burst Switched Networks

Author: T. Venkatesh

Publisher: Springer Science & Business Media

ISBN:

Category: Technology & Engineering

Page: 262

View: 853

This book presents the state of the art results on modeling and analysis of OBS networks. It provides researchers with new directions for future research and helps them gain a better understanding of modeling OBS networks. This book classifies all the literature on modeling and analysis of OBS networks and serves as a thought provoking material for the researchers working on the analysis of high-speed networks. The scope of this book however is not limited to OBS networks alone but extends to high-speed communication networks with limited or no buffers.
Computers

Optical Burst Switched Networks

Author: Jason P. Jue

Publisher: Springer

ISBN:

Category: Computers

Page: 147

View: 648

Next-generation high-speed Internet backbone networks will be required to support a broad range of emerging applications which may not only require significant bandwidth, but may also have strict quality of service (QoS) requirements. Furthermore, the traffic from such applications are expected to be highly bursty in nature. For such traffic, the allocation of static fixed-bandwidth circuits may lead to the over-provisioning of bandwidth resources in order to meet QoS requirements. Optical burst switching (OBS) is a promising new technique which attempts to address the problem of efficiently allocating resources for bursty traffic. In OBS, incoming data is assembled into bursts at the edges of the network, and when the burst is ready to be sent, resources in the network are reserved only for the duration of the burst. The reservation of resources is typically made by an out-of-band one-way control message which precedes the burst by some offset time. By reserving resources only for the duration of the burst, a greater degree of utilization may be achieved in the network. This book provides an overview of optical burst switching. Design and research issues involved in the development of OBS networks are discussed, and approaches to providing QoS in OBS networks are presented. Topics include: - Optical burst switching node and network architectures - Burst assembly - Signaling protocols - Contention resolution - Burst scheduling - Quality of service in OBS networks

Performance Evaluation of Optical Burst Switched Networks

Author: Siamak Azodolmolky

Publisher: LAP Lambert Academic Publishing

ISBN:

Category:

Page: 156

View: 536

This book focuses on the performance evaluation of the Optical Burst Switched (OBS) networks. A simulation framework based on OPNET Modeler is designed and implemented to evaluate the performance of an OBS network in the presence of self-similar traffic sources. The impact of self-similar traffic sources and specific design parameters imposed on the network is assessed in terms of burst assembly delay, its jitter and burst loss ratio. The performance metrics have a strong dependency on parameters such as number of packets per burst, assembly timeout, number of available wavelengths and the degree of the traffic self-similarity. Furthermore, the impact of time and size-based burst assembly algorithms utilized in edge routers, on the self-similarity level of the output traffic, is evaluated. Both static & adaptive approaches are examined. This research utilizes the OPNET Modeler(r) focusing on the characteristics of the output traffic. Various Hurst parameter estimators have been applied to estimate the Hurst parameter of the aggregated input and output traffic streams. The performance impact of the burst assembly approaches in terms of burst assembly delay and its jitter is measured.

A Study of Optical Burst Switched Networks with the Jumpstart Just In Time Signaling Protocol

Author:

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ISBN:

Category:

Page:

View: 104

This thesis studies the optical burst switched (OBS) networks. It consists of three parts. In the first part, we present a detailed analysis of three major wavelength reservation schemes for OBS networks: JIT, JET, and Horizon. The contributions include: (i) analytical models of JET and Horizon (on a single OBS node) that are more accurate than previously published ones and valid for general burst length and offset length distributions; (ii) determination of the regions of parameter values, such as burst offset length, optical switching and hardware processing overheads, so that a more complex reservation scheme reduces to a simpler one; and (iii) a new reservation scheme, JIT+, which is as simple to implement as JIT, and its performance tracks that of Horizon and JET. We compare the performance (in terms of burst drop probability) of the four wavelength reservation schemes on a single OBS node, as well as on a path of OBS nodes with cross traffic, under various sets of parameter values. Our major finding is that, under reasonable assumptions regarding the current and future state-of-the-art technologies in optical switch and electronic hardware, the simplicity of JIT and JIT+ seems to outweigh any performance benefits of Horizon and JET. In the second part of this thesis, we present the results of a simulation analysis of OBS networks employing the Jumpstart JIT signaling protocol. We study the performance of various network topologies in terms of burst drop probability and investigate the effects of several system parameters, including message processing time, OXC configuration delay, user-to-switch propagation delay, and switch-to-switch propagation delay. We also investigate the effect of wavelength converters. In the third part, we develop a suite of adaptive and non-adaptive wavelength assignment policies for OBS networks. We also apply traffic engineering techniques to reduce wavelength contention through traffic isolation. Our performance study indicates tha.
Technology & Engineering

An Analytical Approach to Optical Burst Switched Networks

Author: T. Venkatesh

Publisher: Springer

ISBN:

Category: Technology & Engineering

Page: 262

View: 624

This book presents the state of the art results on modeling and analysis of OBS networks. It provides researchers with new directions for future research and helps them gain a better understanding of modeling OBS networks. This book classifies all the literature on modeling and analysis of OBS networks and serves as a thought provoking material for the researchers working on the analysis of high-speed networks. The scope of this book however is not limited to OBS networks alone but extends to high-speed communication networks with limited or no buffers.

Performance Analysis of Optical Burst Switched Networks with Dynamic Simultaneous Link Possession

Author:

Publisher:

ISBN:

Category:

Page:

View: 612

Given the current state of the technology, the Optical Burst Switched (OBS) architecture is a practical optical switching solution for the optical networks. In OBS, the user data is transmitted in variable size data units, called bursts, which travel as an optical signal along the entire route. The control information for each burst is transmitted prior to its corresponding burst and it is electronically processed at each hop along the route. The dynamic nature of OBS allows for network adaptability and scalability, which makes it very suitable for the transmission of bursty traffic. In this thesis we study and analyze the performance of OBS networks. We consider the case when the bursts are large enough to simultaneously hold wavelengths on multiple links along the route. Since the size of the bursts varies and the link distance between two adjacent network nodes also varies, a burst may simultaneously occupy wavelengths on a variable number of links as it travels from its source to its destination. As the burst propagates through the network, it dynamically acquires and releases wavelengths from link to link. In this thesis, we propose queueing network models that feature dynamic simultaneous link possession and analyze them in order to obtain the end-to-end burst loss probabilities. This thesis is structured into five parts. In the first part, we describe the Optical Burst Switch architecture and summarize its main design components. In the second part, we define and motivate the simultaneous link possession problem. In the third part, we study an OBS network where the bursts are large enough to simultaneously hold wavelengths on one or two consecutive links. In the fourth part of this thesis, we analytically study an OBS network with simultaneous link possession and a very large number of wavelengths per link. In the fifth part, we address the problem of how to analytically evaluate the performance of OBS networks when the arrival traffic is bursty.

Performance Analysis of Optical Burst Switched Networks

Author:

Publisher:

ISBN:

Category:

Page:

View: 210

In this dissertation, we studied the performance of Optical Burst Switching (OBS). OBS is a promising new solution for the next-generation optical Internet. In the first part of the dissertation, we studied a novel WDM ring network with OBS. The ring consists of N nodes, and each node owns a home wavelength on which it transmits its bursts. The ring operates under the fixed transmitter tunable receiver (FTTR) scheme. Control information is transmitted on a separate control channel. We proposed five different burst switching access protocols. We also studied the performance of these access protocols in terms of throughput, packet delay, throughput fairness, and delay fairness under different network parameters: average packet arrival rate, maximum burst size, and minimum burst size. Finally, we proposed a new offset calculation method, which can significantly simplify the access protocol design, and reduce the packet delay for all access protocols. In the second part of the dissertation, we analyzed an edge node of a WDM OBS mesh network using a new burst arrival process, which is more realistic than the well-known Poisson process. The edge node is modeled as a closed non-product-form queueing network, consisting of special nodes with orbiting customers. Despite the rich literature in queueing network analysis, this particular queueing network with orbiting customers has not been analyzed before. We developed algorithms for both the single-class and multi-class queueing networks. The single-class queueing network is solved using Marie's method. In the case of no converters, we obtained a closed-form expression of the conditional throughput of the special node with orbiting customers. The multi-class queueing network is analyzed by decomposition. Specifically, a multiple-class queueing network is decomposed into a set of two-class queueing networks, and each of them is then solved by Neuse and Chandy's Heuristic Aggregation Method. We also developed a much faster appr.
Packet switching (Data transmission)

Burst Scheduling, Grooming and QoS Provisioning in Optical Burst-switched Networks

Author: Yuqi Fan

Publisher:

ISBN:

Category: Packet switching (Data transmission)

Page: 203

View: 982

The demand of network capacity has been increasing steadily with more users than ever connected to the Internet through broadband access and the popularity of video based applications, such as YouTube. Optical wavelength division multiplexing (WDM) networks are expected to form the next-generation backbone network and to fulfill the insatiable appetite for bandwidth. Wavelength routed WDM optical networks offer the granularity of switching at a fiber, waveband, or a wavelength level. The finest granularity offered is at a wavelength level by provisioning lightpaths for different clients/services. All-optical packet switching is still deemed technically infeasible and its competitiveness as a backbone technology is debatable. Optical burst switching (OBS) presents itself as a promising technology for bridging the gap between optical wavelength switching and optical packet switching. OBS operates at the sub-wavelength level and is designed to improve the bandwidth utilization of wavelengths by exploring statistical multiplexing to deal with bursty traffic, and is therefore more resource efficient than optical wavelength switching. In OBS networks, arriving data packets (e.g., IP packets) are assembled at the ingress OBS nodes to form a data burst. A burst control packet (CP) is sent on a control channel ahead of the data burst to reserve resources and configure the switches along the route traversed by the data burst. In this dissertation, we will explore several important and challenging issues in OBS networks in order to improve the utilization of network resource. To reduce the switching overhead, small bursts may be groomed to reduce resource waste and switching penalty. We have studied the per-hop burst grooming problem where bursts with the same next hop may be groomed together to minimize the number of formed larger bursts and strike a proper balance between burst grooming and grooming cost, assuming all the network nodes have the grooming capability. In order to reduce computation overhead and processing delay incurred at the core nodes, we assume that grooming can only be performed at edge nodes and the core node can send a burst to multiple downstream links, that is, the core node has light-splitting capability. We have attempted to groom small bursts into larger bursts, and select a proper route for each large burst, such that total network resources used and/or wasted for delivering the small bursts is minimized. Optical signal transmission quality is subject to various types of physical impairment introduced by optical fibers, switching equipment, or other network components. The signal degradation due to physical impairment may be significant enough such that the bit-error rate of received signals is unacceptably high at the destination, rendering the signal not usable. Based on earlier work, we have studied scheduling and QoS provisioning problems in OBS networks, taking physical impairments into consideration. In the context of the JET signaling protocol, we have studied the burst scheduling problem and proposed three effective burst scheduling algorithms in OBS networks, taking into account physical impairment effects. Because the offset time of bursts varies in OBS networks, the voids or fragmentation on the channels in the outgoing links can severely degrade the network throughput and blocking probability performance, if not dealt with carefully. A signalling architecture called Dual-header Optical Burst Switching (DOBS) is proposed to reduce the scheduling algorithm complexity. We study the burst scheduling problem and propose an impairment aware scheduling algorithm in DOBS networks. QoS provisioning is an important issue in OBS networks. We have dealt with relative QoS support problem and proposed a QoS provisioning algorithm subject to the physical impairment constraints. A high-priority burst requires a better quality of service in terms of blocking probability, and at the same time, the transmission of the burst should satisfy physical impairment constraints.

Routing and Wavelength Assignment in Optical Burst Switching Networks

Author: Kozak Milo

Publisher: LAP Lambert Academic Publishing

ISBN:

Category:

Page: 136

View: 758

OBS provides statistical multiplexing in optical domain, i.e., optical grooming. The principle of OBS is the transmission of the data bursts, which are transport units that carry multiple frames or packets from client network, and just in time channel signaling. These bursts are switched all-optically by an OXC using information carried in BHP. The BHP is transmitted on a dedicated control channel and precedes the burst in order to give some time the core node to process this BHP and configure OXC. Based on the information carried by the BHP the intermediate nodes reserve particular switching resource for the duration of the data burst. The problem efficiency problem of such an approach is tackled in this book. In order to find the maximal use of network topologies, operation research approach was used and column-generation methods helped to find the optimal way of traffic distribution. Nevertheless, this is only the first trial and deeper research is necessary for implementation in real devices.