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Fast recovery time and reduced resource utilization are the two main criteria for determining the quality of survivability
mechanism. Now, it is well known that link-based protection and path-based protection provide, respectively, a short recovery
time and reduced use of resources. To benefit from the both of these saliencies, we propose in this paper to use these mechanisms
simultaneously. Indeed, demands mandating shorter recovery time will be protected using link-based protection. Meanwhile,
other demands (e.g., no-critical) will be protected using path-based protection. Simulation results show that the proposed
solution achieves a good trade-off between resource utilization and recovery time. 相似文献
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In high-speed WDM optical networks, failure recovery is a critical issue as a single element failure in the network will result in the interruption of multiple services. Distributed path restoration is preferable for its high flexibility and efficient resource utilization. However, with the development and maturity of Dense Wavelength Division Multiplexing (DWDM) technology, the resource contention problem arises when simultaneously restoring a large amount of services initiated from many uncoordinated source nodes. This will degrade network performance and result in long service recovery latency. In this paper, we present the Routing Pre-Configuration (RPC) scheme for fast and scalable path restoration in DWDM networks, where pre-failure configuration and post-failure signaling are demonstrated. We compare it with the previous contention resolution approaches and the simulation results prove its improvement in restoration blocking probability and average restoration time. 相似文献
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Internet Service Providers (ISP) need to support Quality-of-Service (QoS) constrains in Internet multicast applications which
are often delay-sensitive and demanding on network resources. This paper proposes a QoS-constraint multicast restoration scheme
in WDM mesh networks based on 2-tuple domination core node selection algorithm which minimization of total network resources
in “hop-count” as metric while meeting the “delay-constraint” as a second metric. The primary aim of this work is to provide
fast inter- and intra-domain routings and steady local survivability with QoS-constraints based on the information obtained
from the core nodes. Our simulation results show that the proposed algorithm outperforms the Dual Tree and MRLR algorithms
in terms of the minimum restoration time needed for all recovery paths, blocking probability based on the minimum restoration
time, instead of minimum hop count in our previous study [1], for different network topologies. 相似文献
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Qing Liu Chongyang Xie Tannous Frangieh Nasir Ghani Ashwin Gumaste Nageswara S. V. Rao 《Photonic Network Communications》2009,17(1):63-74
This paper studies routing scalability in multi-domain DWDM networks. Although inter-domain provisioning has been well studied
for packet/cell-switching networks, the wavelength dimension (along with wavelength conversion) poses many challenges in multi-domain
DWDM settings. To address these concerns a detailed GMPLS-based hierarchical routing framework is proposed for multi-domain
DWDM networks with wavelength conversion. This solution uses mesh topology abstraction schemes to hide domain-internal state.
However related inter-domain routing loads can be significant here, growing by the square of the number of border nodes. To
address these scalability limitations, improved inter-domain routing update strategies are also proposed and the associated
performance of inter-domain lightpath RWA and signaling schemes studied.
相似文献
Nasir GhaniEmail: |
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This article studies multi-constraints least-cost multicast routing problem in internet protocol over dense wavelength division multiplexing (IP/DWDM) networks. To address this problem, an individual-difference-based quantum genetic algorithm (IDQGA) is proposed. This algorithm considers individual differences among chromosomes by introducing an adaptive rotation angle step determination scheme and a grouping-based quantum mutation operation. Simulations are conducted over network topologies. The results indicate that compared with other heuristic algorithms, IDQGA has better optimal performance on solving quality of service (QoS) multicast routing problem in IP/DWDM networks and is characterized by strong robustness, high success ratio and excellent capability on global searching. 相似文献
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A high-capacity dense wavelength-division multiplexing/subcarrier multiplexing (DWDM/SCM) network based on a self-healing star-bus-ring architecture (SBRA) is proposed and demonstrated. This architecture has a star subnet on the upper level to be a high-capacity infrastructure for the network, several bus subnets on the middle level to offer broad-band channels for multiwavelength signals, and many ring subnets on the lower level to serve a number of nodes. We design remote nodes and bidirectional wavelength add-drop multiplexers (WADMs) by using simple optical switches to reconfigure the network under link failure. We further employ M-quadrature amplitude modulation (M-QAM) and frequency shift-keyed (FSK) signals for downstream and upstream channels, respectively. The SBRA ensures an optical-beat-interference-free (OBI-free) and high-reliability optical network. Finally, we set up an experimental network to demonstrate the feasibility of the proposed architecture. 相似文献
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概述了在2001年OFC会议上出现的新型光无源器件,介绍了光无源器件的最新进展,着重分析了几种用于DWDM光网络中的最新型光无源器件的工作原理和结构。 相似文献
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Tao Deng 《Optical Switching and Networking》2005,2(4):209-216
In wavelength-routed DWDM (Dense Wavelength Division Multiplexing) networks, more and more DPEs (Dynamic Power Equalizers) are being implemented in optical crossconnects or add-drop multiplexers for the purpose of maintaining uniform power on working wavelengths. However, the resultant power correlation among equalized channels, when provided with appropriate link gain settings and channel routes, may form power-interactive virtual loops on which signals can experience continuous power deterioration, iteration by iteration. This paper illustrates how such virtual loops may be formed, and what can be done to avoid them by properly designing the network. We also explain the QoS (Quality of Service) threat posed by virtual loops that can be deliberately created by malicious attackers to result in a network-scale service disruption. Guidelines on improving the network robustness against such attacks are presented as well. 相似文献
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一种在接入网中实现OCDMA/DWDMA的新方法 总被引:2,自引:0,他引:2
研究了光码分多址接入/密集波分复用系统应用于接入网的可行性,分析了使用电编解码器 OCDMA 系统实现码分多址的过程,对激光器谱线宽度的要求和一个 OCDMA 码组的用户使用一个 WDM 信道的可能性。由此得到当 OCDMA 和 DWDM 用现有的成熟技术在接入网中相结合,接入网的接入数量和数据容量将更容易满足要求。 相似文献
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Transparent ultra-long-haul DWDM networks with "broadcast-and-select" OADM/OXC architecture 总被引:2,自引:0,他引:2
Vasilyev M. Tomkos I. Mehendale M. Rhee J.-K. Kobyakov A. Ajgaonkar M. Tsuda S. Sharma M. 《Lightwave Technology, Journal of》2003,21(11):2661-2672
We describe an experimental realization of ultra-long-haul (ULH) networks with dynamically reconfigurable transparent optical add-drop multiplexers (OADMs) and optical cross-connects (OXCs). A simple new approach to dispersion management in ULH dense-wavelength-division-multiplexing (DWDM) transparent optical networks is proposed and implemented, which enables excellent transmission performance while avoiding dispersion compensation on a connection-by-connection basis. We demonstrate "broadcast-and-select" node architectures that take full advantage of this method. Our implementation of signal leveling ensures minimum variations of path-averaged power among the wavelength-division-multiplexing (WDM) channels between the dynamic gain-equalizing nodes and results in uniform nonlinear and spontaneous-emission penalties across the WDM spectrum. We achieve 80/spl times/10.7-Gb/s DWDM networking over 4160 km (52 spans/spl times/80 km each) of all-Raman-amplified symmetric dispersion-managed fiber and 13 concatenated OADMs or 320/spl times/320 wavelength-port OXCs with 320-km node spacing. The WDM channels use 50-GHz grid in C band and the simple nonreturn-to-zero (NRZ) modulation format. The measured Q values exhibit more than a 1.8-dB margin over the forward-error correction threshold for 10/sup -15/ bit-error-rate operation. We compare these results with point-to-point transmission of 80/spl times/10-Gb/s NRZ WDM signals over 4160 km without OADM/OXC and provide detailed characterization of penalties due to optical signal-to-noise-ratio degradation, filter concatenation, and crosstalk. 相似文献
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In this article we investigate the problem of a restoration scheme for IP over WDM networks. Network reliability is gaining importance with the huge volume of traffic carried by such networks. Providing survivability at the optical layer is inherently attractive, but raises many questions and challenges, given the characteristic of optical aggregated lightpath and relatively coarse traffic granularity. The emergence of MPLS and its extension, MP/spl lambda/S, opens up new possibilities for developing simple integrated protection/restoration schemes that can be coordinated at both the IP and optical layers . This article first presents an overview of existing MPLS/MP/spl lambda/S recovery mechanisms. Then we propose a joint two-layer recovery scheme for IP-centric WDM-based optical networks where the optical layer takes the recovery actions first, and subsequently the upper IP layer initiates its own recovery mechanism, if the optical layer does not restore all affected services. A simulation-based analysis shows the benefits of the proposed two-layer recovery scheme over single-layer recovery schemes. We demonstrate the advantages of finer granularity in IP layer recovery and the effectiveness in speed on the optical layer. The impact of several network parameters on recovery performance is also studied in the paper. 相似文献
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