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Annual conference on all-optical networking 1999 - architecture, control, and Management issues

作者： Späth, J IND D-70569 Stuttgart Germany

ISBN: (纸本)0819434361

Dynamic routing in WDM (Wavelength Division Multiplexing) networks is achieving increasing interest due to the expected traffic growth for future optical networks. This contribution concentrates on network performance issues occurring for network operation under dynamic traffic load. In this context, routing strategies play a central role. We show that a new strategy achieves very good performance over a wide load range by making use of three beneficial components: providing multiple pre-calculated alternatives which are selected according to the network planning decisions, dynamic path search to search for routes in the cases where all pre-calculated alternatives are blocked, and an adaptive length limit to avoid on the one hand unnecessary restrictions for low traffic load, and on the other hand very long alternative routes for high traffic load. Moreover, specific effects for the influence of resource allocation strategies in photonic WDM networks are highlighted. This includes the dependence of a routing strategy on conversion degree and the influence of converter usage strategies in networks with partial conversion. The results show that an efficient routing strategy has to take into account various specific aspects of WDM networks to achieve good performance. Finally, we present how results from dynamic routing investigation can help to optimize the network planning process.

关键词： WDM optical transport network routing strategy dynamic routing performance evaluation network planning

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Feasibility demonstrations of hyper-media photonic information networks using prototype WDM broadcast-and-select local network systems

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IEICE TRANSACTIONS ON communicationS 1999年第2期E82B卷 317-325页

作者： Ogawara, M Hiramatsu, A Nishikido, J Yanagiya, M Tsukada, M Yukimatsu, K NTT Opt Network Syst Labs Yokosuka Kanagawa 2390847 Japan NTT Dept Technol Tokyo 1638019 Japan NTT Network Serv Syst Labs Musashino Tokyo 1800012 Japan NTT PC Commun Inc Tokyo 1050004 Japan NTT Telecommun Network Lab Grp Tokyo 1600022 Japan

This paper describes the implementation and demonstration of local networks for the hyper-media photonic information network (HM-PIN), a candidate for the information service platform offering broadcast and telecommunication services. In addition, the feasibility of the HM-PIN is also demonstrated using prototype local network systems. This local network adopts architecture based on wavelength-division-multiplexing (WDM) and broadcast-and-select (B&S) switching, and supports all HM-PIN services except inter-local-network communication. The major issues of this proposed network are the technologies that support many broadcast channels and reduce channel selection cost. This paper also considers the combination of WDM technology and three alternatives: electrical TDM, subcarrier multiplexing (SCM or electrical FDM), and optical TDM (O-TDM). Three 128 ch (8 wavelengths x 16 channels) WDM B&S prototype systems are built to demonstrate the feasibility of the proposed HM-PIN. In WDM/SCM, 30 and 20 Mb/s channels are realized as 16-QAM and 64-QAM, and 155 Mb/s channels are realized by WDM/TDM. Moreover, these three prototypes were connected to form a small HM-PIN and applications such as video distribution and IP datagram cut-through are demonstrated. Furthermore, the delay and throughput of the HM-PIN are evaluated by connecting a local network to a 200-km WDM-ring backbone network. Our discussions and demonstrations confirm the impact and feasibility of the proposed hyper-media photonic information network.

关键词： hyper-media photonic switching broadcast-and-select WDM/TDM WDM/SCM

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QoS support over ultra-fast TDM optical networks

QoS support over ultra-fast TDM optical networks

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Proceedings of the all-optical networking 1999: architecture, control, and Management issues

作者： Narvaez, Paolo Siu, Kai-Yeung Finn, Steven Massachusetts Inst of Technology Cambridge United States

HLAN is a promising architecture to realize Tb/s access networks based on ultra-fast optical TDM technologies. This paper presents new research results on efficient algorithms for the support of quality of service (QoS) over the HLAN network architecture. In particular, we propose a new scheduling algorithm that emulates fair queueing in a distributed manner for bandwidth allocation purpose. The proposed scheduler collects information on the queue of each host on the network and then instructs each host how much data to send. Our new scheduling algorithm ensures full bandwidth utilization, while guaranteeing fairness among all hosts.

关键词： optical communication

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Feasibility demonstrations of hyper-media photonic information networks using prototype WDM broadcast-and-select local network systems

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IEICE TRANSACTIONS ON ELECTRONICS 1999年第2期E82C卷 265-273页

关键词： hyper-media photonic switching broadcast-and-select WDM/TDM WDM/SCM

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Fast optimization of survivable WDM mesh networks based on multiple self-healing rings

Fast optimization of survivable WDM mesh networks based on m...

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Annual conference on all-optical networking 1999 - architecture, control, and Management issues

作者： Fumagalli, A Valcarenghi, L Univ Texas Erik Jonsson Sch Engn & Comp Sci Ctr Adv Telecommun Syst & Sci Richardson TX 75083 USA

ISBN: (纸本)0819434361

As widely recognized, Wavelength Division Multiplexing (WDM) allows to practically harness a considerable portion of the huge transmission capacity offered by the optical fiber. Among the several advantages offered by WDM, the lightpath concept - or wavelength routing - is perhaps the most revolutionary one. To make lightpaths reliable in presence of system faults, protection techniques are necessary directly in the optical layer. Protection against faults in the optical layer can be achieved by means of various schemes. A promising one is based on Multi-Wavelength division multiplexed Self-Healing Ring, or Multi-WSHR for short. However, minimizing the system cost while providing this protection scheme in a general mesh network, e.g., choosing the multi-ring cover, routing the lightpaths and for each lightpath choosing the protecting ring(s), is not a trivial problem. In fact, the optimum solution of this problem may require several hours of CPU time already in networks with few dozens of nodes. This paper presents a fast approach to interactively designing optimal resilient WDM mesh networks based on an optimization engine that, given the network layout, the lightpath demands and the cost function, sub-optimally selects a ring cover and, for each lightpath demand, the route and the protecting rings. The three selections are made jointly as it has been demonstrated that a 15% cost reduction can be achieved in this way when compared to a sequential selection. The optimization engine, based on Simulated Annealing (SA), yields satisfactory solutions with CPU times ranging from seconds to few minutes, thus allowing user interactive design of the system. Ln addition, the inherent flexibility of Sb allows us to minimize the system cost under various Multi-WSHR protection schemes, including Dedicated-Path-switched WSHR (DP-WSHR) and Shared-Line-switched WSHR (SG WSHR). a last feature of the proposed approach is the capability to handle network designs in which, due to part

关键词： optical layer protection and restoration survivable network all-optical network WDM network simulated annealing

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SIMON: A simulator for optical networks

SIMON: A simulator for optical networks

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Proceedings of the all-optical networking 1999: architecture, control, and Management issues

作者： Ramamurthy, Byrav Datta, Debasish Feng, Helena Heritage, Jonathan P. Mukherjee, Biswanath Univ of Nebraska-Lincoln Lincoln United States

SIMON is an object-oriented event-driven simulation package implemented in C++ which incorporates optical device characteristics in the measurement of network-level blocking statistics. SIMON is suitable for studying the performance of large wavelength-routed optical networks, in which a call is set up in the network for a specific duration on a pre-determined lightpath. Currently the physical-layer models allow for modeling phenomena such as signal attenuation in fiber and other components, amplifier gain saturation, and homowavelength crosstalk in switches. Simulation experiments can be performed with a user-specified bit-error rate (BER) limit, which must be satisfied by any call set up in the network.

关键词： optical communication

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New approach to fault-tolerant routing in all-optical networks

New approach to fault-tolerant routing in all-optical networ...

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Proceedings of the all-optical networking 1999: architecture, control, and Management issues

作者： Sengupta, A. alluri, S.K. Bandyopadhyay, S. Jaekel, A. Univ of South Carolina Columbia United States

Fault management in WDM routed all-optical networks has mostly been addressed either by automatic protection switching or through loop-back recovery. These schemes are designed for managing single fault occurrence and generalization method to handle multiple faults are not known. Conventional routing schemes are static in nature (where the routers are programmed to realize the lightpaths between the end-nodes) and hence a fault management scheme needs to find a fault-free path between end-nodes using the settings of the routers. This paper considers the principle of survival route graphs to construct fault-free paths between end-nodes. As a result, the fault avoiding route between two end-nodes might be a multihop route in which the number of hops are limited to reduce the communication delay. The performance degradations of the network because of fault occurrence are studied through simulations and measured in terms of blocking probability and communication delay.

关键词： optical communication

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Intermedia synchronization for videoconference over IP

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SIGNAL PROCESSING-IMAGE communication 1999年第1-2期15卷 149-164页

作者： Bertoglio, L Leonardi, R Migliorati, P Univ Brescia Dept Elect Automat Signals & Commun Lab I-25123 Brescia BS Italy

This paper deals with the problem of audio and video synchronization issues for real-time audio-visual communication over IF-based networks. Starting from the real-time transport protocol (RTP) specifications (Schulzrinne, 1995), it provides an accurate description on how to recover a reliable absolute time reference for audio and video signals from header information in RTP and RTP control protocol packets. Such temporal informations allow to synchronize both media within acceptable perceptual bounds for reconstruction at any receiver end, in a possibly multi-point video-conference. This may occur independently of the fact that all (audio/video) packets reach destination, or that multiple replications of such packets arrive at destination. The proposed solution does not take into account the possible different delays that may be introduced between the different communication points, thus resulting eventually in potential jitters in the reconstruction of the audio-visual streams between different receivers. Each receiver handles its reconstruction independently of any transmission/processing delay. In order to ensure a better quality of the reconstructed material, priority is given to audio information. If the audio stream anticipate the video stream, the receiver simply discards video packets. Conversely, when video is ahead of audio information, the video decoding stage is interrupted till audio information arrives. Experimental simulations over a LAN have demonstrated the validity of the proposed approach. (C) 1999 Elsevier Science B.V. all rights reserved.

关键词： Video conferencing network protocols Internet Synchronization Realtime systems Packet networks Image reconstruction Multimedia systems Signal receivers Image quality

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Differentiated optical Services: A quality of optical service model for WDM networks

Differentiated Optical Services: A quality of optical servic...

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Proceedings of the all-optical networking 1999: architecture, control, and Management issues

作者： Ndousse, Thomas D. Golmie, Nada Natl Inst of Standards and Technology Gaithersburg United States

This paper addresses the issues of guaranteed and scalable end-to-end QoS in Metropolitan DWDM networks serving as transit networks for IP access networks. DWDM offering few wavelengths have in the past been deployed in backbone networks to upgrade point-to-point transmission where sharing is based on coarse granularity. This type of DWDM backbone networks, offering few lightpaths, provides no support for QoS services traversing the network. As DWDM networks with larger numbers of wavelengths penetrate the data-centric Metro environment, specific IP service requirements such as priority restoration, scalability, dynamic provisioning of capacity and routes, and support for coarse-grain QoS capabilities will have to be addressed in the optical domain in order to support end-to-end Service-Level Agreements (SLA). In this paper, we focus on the support of QoS in the optical domain in order to achieve end-to-end QoS over a DWDM network. We propose a QoS service model in the optical domain called Differentiated optical Services (DOS). Service classification in DOS is based on a set of optical parameters that captures the quality and reliability of the optical lightpath.

关键词： optical communication

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Resource allocation for multirate sessions in WDM/TDM rings

Resource allocation for multirate sessions in WDM/TDM rings

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Proceedings of the all-optical networking 1999: architecture, control, and Management issues

作者： Subramaniam, Suresh Harder, Eric J. Choi, Hyeong-Ah George Washington Univ Washington United States

Wavelength utilization in WDM wavelength routing networks can be improved by time division multiplexing sessions on each wavelength, and switching time slots and wavelengths. In this paper, we consider the problem of assigning time slots and wavelengths to a given set of multi-rate sessions in WDM/TDM buses and rings. Given a set of sessions and their time slot requirements, our objective is to maximize the network throughput. Bounds on frame length, and hence network throughput, under two different scheduling constraints are presented. Simulation results using a simple assignment algorithm that achieves near-optimal frame lengths are also presented.

关键词： optical communication

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