191 research outputs found

    Architecture, design, and modeling of the OPSnet asynchronous optical packet switching node

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    An all-optical packet-switched network supporting multiple services represents a long-term goal for network operators and service providers alike. The EPSRC-funded OPSnet project partnership addresses this issue from device through to network architecture perspectives with the key objective of the design, development, and demonstration of a fully operational asynchronous optical packet switch (OPS) suitable for 100 Gb/s dense-wavelength-division multiplexing (DWDM) operation. The OPS is built around a novel buffer and control architecture that has been shown to be highly flexible and to offer the promise of fair and consistent packet delivery at high load conditions with full support for quality of service (QoS) based on differentiated services over generalized multiprotocol label switching

    New dynamic bandwidth allocation algorithm analysis: DDSPON for ethernet passive optical networks

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    This project aims to present the state of the art in Dynamic Bandwidth Allocation (DBA) solutions, as well as the study and evaluation of one proposal of DBA algorithm: the Distributed Dynamic Scheduling for EPON (DDSPON), which is the UPC contribution to the research in scheduling algorithms for EPON

    Multimedia Traffic Routing in Multilayer WDM Networks

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    The advent of real-time multimedia services over the Internet has stimulated new technologies for expanding the information carrying capacity of optical network backbones. Multilayer wavelength division multiplexing (WDM) packet switching is an emerging technology for increasing the bandwidth of optical networks. Two algorithms for the routing of the multimedia traffic flows were applied: (i) Capacitated Shortest Path First (CSPF) routing, which minimizes the distance of each flow linking the given source and destination nodes and satisfying capacity constraints; and (ii) Flow Deviation Algorithm (FDA) routing, which minimizes the network-wide average packet delay.Comment: 10 pages, 8 figure

    Node design in optical packet switched networks

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    Protection architectures for multi-wavelength optical networks.

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    by Lee Chi Man.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.Includes bibliographical references (leaves 63-65).Abstracts in English and Chinese.Chapter CHAPTER 1 --- INTRODUCTION --- p.5Chapter 1.1 --- Background --- p.5Chapter 1.1.1 --- Backbone network - Long haul mesh network problem --- p.5Chapter 1.1.2 --- Access network ´ؤ Last mile problems --- p.8Chapter 1.1.3 --- Network integration --- p.9Chapter 1.2 --- SUMMARY OF INSIGHTS --- p.10Chapter 1.3 --- Contribution of this thesis --- p.11Chapter 1.4 --- Structure of the thesis --- p.11Chapter CHAPTER 2 --- PREVIOUS PROTECTION ARCHITECTURES --- p.12Chapter 2.1 --- Introduction --- p.12Chapter 2.2 --- Traditional physical protection architectures in metro area --- p.13Chapter 2.2.1 --- Self healing ring --- p.17Chapter 2.2.2 --- Some terminology in ring protection --- p.13Chapter 2.2.3 --- Unidirectional path-switched rings (UPSR) [17] --- p.13Chapter 2.2.4 --- Bidirectional line-switched rings (BLSR) [17] --- p.14Chapter 2.2.5 --- Ring interconnection and dual homing [17] --- p.16Chapter 2.3 --- Traditional physical protection architectures in access networks --- p.17Chapter 2.3.1 --- Basic architecture in passive optical networks --- p.17Chapter 2.3.2 --- Fault management issue in access networks --- p.18Chapter 2.3.3 --- Some protection architectures --- p.18Chapter 2.4 --- Recent protection architectures on a ccess networks --- p.21Chapter 2.4.1 --- Star-Ring-Bus architecture --- p.21Chapter 2.5 --- Concluding remarks --- p.22Chapter CHAPTER 3 --- GROUP PROTECTION ARCHITECTURE (GPA) FOR TRAFFIC RESTORATION IN MULTI- WAVELENGTH PASSIVE OPTICAL NETWORKS --- p.23Chapter 3.1 --- Background --- p.23Chapter 3.2 --- Organization of Chapter 3 --- p.24Chapter 3.3 --- Overview of Group Protection Architecture --- p.24Chapter 3.3.1 --- Network architecture --- p.24Chapter 3.3.2 --- Wavelength assignment --- p.25Chapter 3.3.3 --- Normal operation of the scheme --- p.25Chapter 3.3.4 --- Protection mechanism --- p.26Chapter 3.4 --- Enhanced GPA architecture --- p.27Chapter 3.4.1 --- Network architecture --- p.27Chapter 3.4.2 --- Wavelength assignment --- p.28Chapter 3.4.3 --- Realization of network elements --- p.28Chapter 3.4.3.1 --- Optical line terminal (OLT) --- p.28Chapter 3.4.3.2 --- Remote node (RN) --- p.29Chapter 3.4.3.3 --- Realization of optical network unit (ONU) --- p.30Chapter 3.4.4 --- Protection switching and restoration --- p.31Chapter 3.4.5 --- Experimental demonstration --- p.31Chapter 3.5 --- Conclusion --- p.33Chapter CHAPTER 4 --- A NOVEL CONE PROTECTION ARCHITECTURE (CPA) SCHEME FOR WDM PASSIVE OPTICAL ACCESS NETWORKS --- p.35Chapter 4.1 --- Introduction --- p.35Chapter 4.2 --- Single-side Cone Protection Architecture (SS-CPA) --- p.36Chapter 4.2.1 --- Network topology of SS-CPA --- p.36Chapter 4.2.2 --- Wavelength assignment of SS-CPA --- p.36Chapter 4.2.3 --- Realization of remote node --- p.37Chapter 4.2.4 --- Realization of optical network unit --- p.39Chapter 4.2.5 --- Two types of failures --- p.40Chapter 4.2.6 --- Protection mechanism against failure --- p.40Chapter 4.2.6.1 --- Multi-failures of type I failure --- p.40Chapter 4.2.6.2 --- Type II failure --- p.40Chapter 4.2.7 --- Experimental demonstration --- p.41Chapter 4.2.8 --- Power budget --- p.42Chapter 4.2.9 --- Protection capability analysis --- p.42Chapter 4.2.10 --- Non-fully-connected case and its extensibility for addition --- p.42Chapter 4.2.11 --- Scalability --- p.43Chapter 4.2.12 --- Summary --- p.43Chapter 4.3 --- Comparison between GPA and SS-CPA scheme --- p.43Chapter 4.1 --- Resources comparison --- p.43Chapter 4.2 --- Protection capability comparison --- p.44Chapter 4.4 --- Concluding remarks --- p.45Chapter CHAPTER 5 --- MUL 77- WA VELENGTH MUL TICAST NETWORK IN PASSIVE OPTICAL NETWORK --- p.46Chapter 5.1 --- Introduction --- p.46Chapter 5.2 --- Organization of this chapter --- p.47Chapter 5.3 --- Simple Group Multicast Network (SGMN) scheme --- p.47Chapter 5.3.1 --- Network design principle --- p.47Chapter 5.3.2 --- Wavelength assignment of SGMN --- p.48Chapter 5.3.3 --- Realization of remote node --- p.49Chapter 5.3.3 --- Realization of optical network unit --- p.50Chapter 5.3.4 --- Power budget --- p.51Chapter 5.4 --- A mulTI- wa velength a ccess network with reconfigurable multicast …… --- p.51Chapter 5.4.1 --- Motivation --- p.51Chapter 5.4.2 --- Background --- p.51Chapter 5.4.3 --- Network design principle --- p.52Chapter 5.4.4 --- Wavelength assignment --- p.52Chapter 5.4.5 --- Remote Node design --- p.53Chapter 5.4.6 --- Optical network unit design --- p.54Chapter 5.4.7 --- Multicast connection pattern --- p.55Chapter 5.4.8 --- Multicast group selection in OLT --- p.57Chapter 5.4.9 --- Scalability --- p.57Chapter 5.4.10 --- Experimental configuration --- p.58Chapter 5.4.11 --- Concluding remarks --- p.59Chapter CHAPTER 6 --- CONCLUSIONS --- p.60LIST OF PUBLICATIONS: --- p.62REFERENCES: --- p.6

    Evaluating the energy consumption and the energy savings potential in ICT backbone networks

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    Multi-layer survivability in IP-over-WDM networks

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    Ph.DDOCTOR OF PHILOSOPH

    Traffic engineering in dynamic optical networks

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    Traffic Engineering (TE) refers to all the techniques a Service Provider employs to improve the efficiency and reliability of network operations. In IP over Optical (IPO) networks, traffic coming from upper layers is carried over the logical topology defined by the set of established lightpaths. Within this framework then, TE techniques allow to optimize the configuration of optical resources with respect to an highly dynamic traffic demand. TE can be performed with two main methods: if the demand is known only in terms of an aggregated traffic matrix, the problem of automatically updating the configuration of an optical network to accommodate traffic changes is called Virtual Topology Reconfiguration (VTR). If instead the traffic demand is known in terms of data-level connection requests with sub-wavelength granularity, arriving dynamically from some source node to any destination node, the problem is called Dynamic Traffic Grooming (DTG). In this dissertation new VTR algorithms for load balancing in optical networks based on Local Search (LS) techniques are presented. The main advantage of using LS is the minimization of network disruption, since the reconfiguration involves only a small part of the network. A comparison between the proposed schemes and the optimal solutions found via an ILP solver shows calculation time savings for comparable results of network congestion. A similar load balancing technique has been applied to alleviate congestion in an MPLS network, based on the efficient rerouting of Label-Switched Paths (LSP) from the most congested links to allow a better usage of network resources. Many algorithms have been developed to deal with DTG in IPO networks, where most of the attention is focused on optimizing the physical resources utilization by considering specific constraints on the optical node architecture, while very few attention has been put so far on the Quality of Service (QoS) guarantees for the carried traffic. In this thesis a novel Traffic Engineering scheme is proposed to guarantee QoS from both the viewpoint of service differentiation and transmission quality. Another contribution in this thesis is a formal framework for the definition of dynamic grooming policies in IPO networks. The framework is then specialized for an overlay architecture, where the control plane of the IP and optical level are separated, and no information is shared between the two. A family of grooming policies based on constraints on the number of hops and on the bandwidth sharing degree at the IP level is defined, and its performance analyzed in both regular and irregular topologies. While most of the literature on DTG problem implicitly considers the grooming of low-speed connections onto optical channels using a TDM approach, the proposed grooming policies are evaluated here by considering a realistic traffic model which consider a Dynamic Statistical Multiplexing (DSM) approach, i.e. a single wavelength channel is shared between multiple IP elastic traffic flows

    Optisen liityntäverkon ohjelmoitavien logiikkapiirien ohjelmoinnin suunnittelu

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    Tiedonsiirtoverkkojen rakenne elää muutoksen aikaa. Perinteisesti data-, puhelin- ja laajakaistaliikenne on siirretty erillisissä verkoissa, joiden samanaikainen ylläpitäminen tuottaa ylimääräisiä kustannuksia operaattoreille. Lisäksi uudet interaktiiviset palvelut vaativat toimiakseen sellaista palvelunlaatua, jota nykyiset tiedonsiirtoverkot eivät kykene tarjoamaan. Näiden epäkohtien johdosta tiedonsiirtoverkkojen kehityksessä tähdätään uusiin, entistä joustavampiin ja eri toiminnot yhdistäviin verkkoratkaisuihin, joissa tiedonsiirron palvelunlaadulla on entistä suurempi merkitys. Tällä hetkellä tiedonsiirtoverkkojen kokonaistiedonsiirtonopeuden kasvun pullonkaulatekijäksi on muodostunut kaupunkialueiden syöttöverkkojen monimutkaisuus, millä on suuri vaikutus myös tiedonsiirron palvelunlaatuun. TEKES-rahoitteisessa OAN-projektissa kehitetään uutta ja yksinkertaisempaa kaupunkialueen optista syöttöverkkoratkaisua, jolla alueen palvelunlaatua saataisiin parannettua. Tämä diplomityö on tehty osana OAN-projektia. Työssä kuvataan tiedonsiirtoverkkojen tämänhetkinen rakenne, tarkastellaan sen ongelmia ja tulevaisuuden kehityssuuntia, sekä esitetään pohdintojen pohjalta rakennettu malli tulevaisuuden tiedonsiirtoverkkojen rakenteelle. Työssä esitetään myös HDL-implementointiprosessiin kuuluvat työvaiheet sekä käydään läpi suunnitelma OAN-projektissa toteutettavan prototyypin ohjelmoitavien logiikkapiirien ohjelmaa varten
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