Resilient optical multicasting utilizing cycles in WDM optical networks

High capacity telecommunications of today is possible only because of the presence of optical networks. At the heart of an optical network is an optical fiber whose data carrying capabilities are unparalleled. Multicasting is a form of communication in wavelength division multiplexed (WDM) networks that involves one source and multiple destinations. Light trees, which employ light splitting at various nodes, are used to deliver data to multiple destinations. A fiber cut has been estimated to occur, on an average, once every four days by TEN, a pan-European carrier network. This thesis presents algorithms to make multicast sessions survivable against component failures. We consider multiple link failures and node failures in this work. The two algorithms presented in this thesis use a hybrid approach which is a combination of proactive and reactive approaches to recover from failures. We introduce the novel concept of minimal-hop cycles to tolerate simultaneous multiple link failures in a multicast session. While the first algorithm deals only with multiple link failures, the second algorithm considers the case of node failure and a link failure. Two different versions of the first algorithm have been implemented to thoroughly understand its behavior. Both algorithms were studied through simulators on two different networks, the USA Longhaul network and the NSF network. The input multicast sessions to all our algorithms were generated from power efficient multicast algorithms that make sure the power in the receiving nodes are at acceptable levels. The parameters used to evaluate the performance of our algorithms include computation times, network usage and power efficiency. Two new parameters, namely, recovery times and recovery success probability, have been introduced in this work. To our knowledge, this work is the first to introduce the concept of minimal hop cycles to recover from simultaneous multiple link failures in a multicast session in optical networks

Isochronets: a High-Speed Network Switching Architecture

Traditional switching techniques need hundred- or thousand-MIPS processing power within switches to support Gbit/s transmission rates available today. These techniques anchor their decision-making on control information within transmitted frames and thus must resolve routes at the speed in which frames are being pumped into switches. Isochronets can potentially switch at any transmission rate by making switching decisions independent of frame contents. Isochronets divide network bandwidth among routing trees, a technique called Route Division Multiple Access (RDMA). Frames access network resources through the appropriate routing tree to the destination. Frame structures are irrelevant for switching decisions. Consequently, Isochronets can support multiple framing protocols without adaptation layers and are strong candidates for all-optical implementations. All network-layer functions are reduced to an admission control mechanism designed to provide quality of service (QOS) guarantees for multiple classes of traffic. The main results of this work are: (1) A new network architecture suitable for high-speed transmissions; (2) An implementation of Isochronets using cheap off-theshelf components; (3) A comparison of RDMA with more traditional switching techniques, such as Packet Switching and Circuit Switching; (4) New protocols necessary for Isochronet operations; and (5) Use of Isochronet techniques at higher layers of the protocol stack (in particular, we show how Isochronet techniques may solve routing problems in ATM networks)

Survivable mesh-network design & optimization to support multiple QoP service classes

Every second, vast amounts of data are transferred over communication systems around the world, and as a result, the demands on optical infrastructures are extending beyond the traditional, ring-based architecture. The range of content and services available from the Internet is increasing, and network operations are constantly under pressure to expand their optical networks in order to keep pace with the ever increasing demand for higher speed and more reliable links

Design of power efficient multicast algorithms for sparse split WDM networks

Recent years witnessed tremendous increase in data traffic as new Internet applications were launched. Optical networks employing recent technologies such as DWDM and EDFA`s emerged as the most prominent and most promising solutions in terms of their ability to keep with the demand on bandwidth. However for a class of applications bandwidth is not the only important requirement, These applications require efficient multicast operations. They include data bases, audio/video conferencing, distributed computing etc. Multicasting in the optical domain however has its own unique set of problems. First, an optical signal can be split among the outputs of a node but the power due to splitting can be significantly reduced. Second, the hardware for split nodes is relatively expensive and therefore we cannot afford to employ it at every node. Third, there are other sources of losses such as attenuation losses and multiplexing /de-multiplexing losses. This thesis deals with the important issue of Power Efficient multicast in WDM optical networks. We report three new algorithms for constructing power efficient multicast trees and forests. Our algorithms are the first to take into account all possible sources of power losses while constructing the trees. We utilize the techniques of backtracking and tree pruning judiciously to achieve very power efficient multicast trees. The first two algorithms use modified versions of the shortest path heuristic to build the tree. The third algorithm however, uses a novel concept and considers power at every tree building step. In this algorithm, the order of inclusion of destination nodes into the tree is based on the power distribution in the tree and not distance. All three algorithms prune the trees if the power levels at the destinations are not acceptable. The performance of these three algorithms under several constraints is studied on several irregular topologies. All three algorithms reported in this work produce significant improvements in signal strength at the set of destinations over the existing multicast algorithms. Numerical results show that our third algorithm outperforms the first two algorithms as well as the existing multicasting algorithms

Isochronets: A High-speed Network Switching Architecture

Traditional network architectures present two main limitations when applied to High- Speed Networks (HSNs): they do not scale with link speeds and they do not adequately support the Quality of Service (QoS) needs of high-performance applications. This thesis introduces the Isochronets architecture that overcomes both limitations. Isochronets view frame motions over links in analogy to motions on roads. In the latter, traffic lights can synchronize to create green waves of uninterrupted motion. Isochronets accomplish similar uninterrupted motion by periodically configuring network switches to create end-to-end routes in the network. Frames flow along these routes with no required header processing at intermediate switches. Isochronets offer several advantages. First, they are scaleable with respect to transmission speeds. Switches merely configure routes on a time scale that is significantly longer than and independent of the average frame transmission time. Isochronets do not require frame processing and thus avoid conversions from optical to electronic representations. They admit efficient optical transmissions under electronically controlled switches. Second, Isochronets ensure QoS for high-performance applications in terms of latency, jitter, loss, and other service qualities. Isochronet switches can give priority to frames arriving from selected links. At one extreme, they may give a source the right-of-way to the destination by assigning priority to all links in its path. Additionally, other sources may still transmit at lower priority. At the other extreme, they may give no priority to sources and frames en route to the same destination contend for intermediate links. In between, Isochronets can accomplish a myriad of priority allocations with diverse QoS. Third, Isochronets can support multiple protocols without adaptation between different frame structures. End nodes view the network as a media access layer that accepts frames of arbitrary structure. The main contributions of this thesis are: Design of the Isochronets architecture. Design and implementation of a gigabit per second Isochronet switch (Isoswitch). Definition of the Loosely-synchronous Transfer Mode (LTM) and the Synchronous Protocol Stack (SPS) that add synchronous and isochronous services to any existing protocol stack. Performance evaluation of Isochronets

Survivability schemes for dynamic traffic in optical networks

Ph.DDOCTOR OF PHILOSOPH

Power efficient survivable routing with p-cycles

Power awareness in networking has been a vital area of research in wireless networks but, until recently, has been largely ignored in wired networks. In wireless applications, the amount of power utilized by transmission is of vital importance since it will limit factors such as battery life and transmission range. In wired networks, the power issues of wireless networks do not arise since the wired networks receive their power from the power grid. However, the problem of operational costs and the environmental impact of wired networks have become increasingly important issues in recent years. This thesis proposes a power efficient routing scheme to address the environmental and operational cost issues. The operational costs of a wired network can be reduced by reducing the amount of power the network utilizes. The proposed power efficient routing scheme utilizes a demand prediction algorithm to determine a set of expected future traffic. The set of expected traffic is then assigned paths in the network using an energy efficient routing algorithm. The paths that are assigned to the predicted traffic are used to assign paths to the real traffic as it enters the network. By continuously updating the set of expected traffic, and the paths that are assigned to the expected traffic, the energy efficient routing algorithm can maintain an energy efficient routing solution over time, and thus, power efficiency is achieved

Self-healing network architectures for multiwavelength optical metro/access networks.

Sun Xiaofeng.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.Includes bibliographical references (leaves 61-64).Abstracts in English and Chinese.Chapter CHAPTER 1 --- INTRODUCTION --- p.1Chapter 1.1 --- Optical network evolution --- p.2Chapter 1.1.1 --- Submarine and terrestrial long-haul fibre systems --- p.2Chapter 1.1.2 --- Metropolitan networks --- p.3Chapter 1.1.3 --- Access networks --- p.4Chapter 1.2 --- Motivation of this thesis --- p.6Chapter 1.3 --- Outline of this thesis --- p.7Chapter CHAPTER 2 --- PREVIOUS SELF-HEALING NETWORK ARCHITECTURES --- p.9Chapter 2.1 --- Introduction --- p.10Chapter 2.1.1 --- Previous protection architectures for access networks --- p.10Chapter 2.1.2 --- Previous protection architectures for metro access networks --- p.13Chapter 2.3 --- Previous protection architectures for metro backbone networks --- p.15Chapter 2.3.1 --- Unidirectional path-switched rings (UPSR) --- p.15Chapter 2.3.2 --- Bidirectional line-switched rings (BLSR) --- p.16Chapter 2.3.3 --- Ring interconnection and dual homing --- p.17Chapter 2.4 --- Summary --- p.19Chapter CHAPTER 3 --- SELF-HEALING NETWORK ARCHITECTURE FOR WDM OPTICAL ACCESS NETWORKS --- p.20Chapter 3.1 --- Introduction --- p.21Chapter 3.2 --- Star-Ring Protection Architecture (SRPA) --- p.21Chapter 3.2.1 --- Motivation --- p.21Chapter 3.2.2 --- Network topology of SRPA --- p.22Chapter 3.2.3 --- Wavelength assignment of SRPA --- p.22Chapter 3.2.4 --- Structure of ONU --- p.23Chapter 3.2.5 --- Protection mechanism --- p.25Chapter 3.2.6 --- Experimental demonstration --- p.26Chapter 3.2.7 --- Power budget --- p.28Chapter 3.2.8 --- Summary --- p.28Chapter 3.3 --- Duplicated-Tree Protection Architecture (DTPA) --- p.28Chapter 3.3.1 --- Motivation --- p.28Chapter 3.3.2 --- Network topology and wavelength assignment --- p.29Chapter 3.3.3 --- Structure of OLT --- p.30Chapter 3.3.4 --- Protection mechanism --- p.31Chapter 3.3.5 --- Experimental demonstration --- p.33Chapter 1.1.1 --- Summary --- p.34Chapter 1.4 --- Summary --- p.35Chapter CHAPTER 4 --- SINGLE-FIBER SELF-HEALING WDM RING NETWORK ARCHITECTURE FOR METRO ACCESS NETWORKS --- p.36Chapter 4.1 --- Introduction --- p.37Chapter 4.2 --- Network architecture and wavelength assignment --- p.37Chapter 4.3 --- Structure of access node --- p.39Chapter 4.4 --- Structure of hub node --- p.40Chapter 4.5 --- Protection mechanism --- p.42Chapter 4.6 --- Experimental demonstration --- p.43Chapter 4.7 --- Optimization of access node --- p.47Chapter 4.8 --- Scalability --- p.48Chapter 4.9 --- Summary --- p.49Chapter CHAPTER 5 --- SELF-HEALING WDM MESH NETWORK ARCHITECTURE FOR METRO BACKBONE NETWORKS… --- p.50Chapter 5.1 --- Introduction --- p.51Chapter 5.2 --- Network architecture and node structure --- p.51Chapter 5.3 --- Protection mechanism --- p.53Chapter 5.4 --- Experimental demonstration --- p.55Chapter 5.5 --- Summary --- p.57Chapter CHAPTER 6 --- SUMMARYAND FUTURE WORKS --- p.58Chapter 6.1 --- Summary of the Thesis --- p.59Chapter 6.2 --- Future Works --- p.59LIST OF PUBLICATIONS --- p.61REFERENCES --- p.6