共查询到20条相似文献,搜索用时 31 毫秒
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S. Sedef Savas Ferhat Dikbiyik M. Farhan Habib Massimo Tornatore Biswanath Mukherjee 《Photonic Network Communications》2014,28(2):123-134
Cloud services delivered by high-capacity optical datacenter networks are subject to disasters which may cause large-area failures, leading to huge data loss. Survivable service provisioning is crucial to minimize the effects of network/datacenter failures and maintain critical services in case of a disaster. We propose a novel disaster-aware service-provisioning scheme that multiplexes service over multiple paths destined to multiple servers/datacenters with manycasting. Our scheme maintains some bandwidth (i.e., degraded service) after a disaster failure vs. no service at all. We formulate this problem into a mathematical model which turns out to be an Integer Linear Program (ILP), and we provide heuristic optimization approaches as ILP is intractable for large problem instances. Numerical examples show that exploiting manycasting by intelligently selecting destinations in a risk-aware manner for service provisioning offers high level of survivability against link and node failures that may be caused by disasters and post-disaster failures at no extra cost compared to the other survivable schemes. 相似文献
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Network virtualization is a promising way to overcome the current ossification of the Intemet. It is essential challenge to find effective, efficient and robust embedding algorithms for recovering virtual network. The virtual network mapping algorithm based on integer programming which was proposed months ago. But it did consider the faults of physical network resources, which is so called survivable virtual network embedding (VNE) problem. Previous strategies for enabling survivability in network virtualization focused on providing protection for the physical network or enhancing the virtual networks by providing backup physical resources in advance, and treated all the physical failures as link failures. In the article, a dynamic recovery method is proposed to solve the survivable virtual network embedding problem based on the integer programming VNE algorithm. The dynamic recovery method doesn't need to backup physical resources and it makes more substrate resources which can be used in the embedding. The dynamic recovery process will be activated only when physical failures occur. Different algorithms are used to recovery node and link failures. Simulations show that the method helps to recover almost all of physical failures by finding the substitute nodes and paths, and its performance is very close to that of pure VNE method without considering physical failures. 相似文献
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The prospect of broadband telecommunication networks loaded with massive quantities of information due to the wide range of services being supported stimulates extra concern for network survivability. As the effect of span or node failures could be drastic, rapid restoration strategies are imperative. This paper describes restoration techniques involving the control of digital crossconnect systems, and the exploitation of spare capacity which has been economically planned into the network. This represents a more extensive approach to survivability than straightforward protection switching, thus improving network reliability 相似文献
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生存性虚拟光网络映射是提高光网络应对灾难故障的重要技术保障措施。为解决灾难性多区域故障导致弹性光网络的带宽容量损失问题,该文提出基于灾难预测故障模型的蚁群优化虚拟光网络映射 (DFM-ACO-VNM)算法。在该算法中,设计基于光节点资源和相邻链路的全局潜在故障概率的光节点排序映射准则,并设计启发式信息公式实现多区域故障下最小带宽容量损失的虚拟节点和虚拟链路协同映射。仿真结果表明,该文所提算法在多区域故障时能降低带宽容量损失,减少带宽阻塞率和提高频谱利用率。 相似文献
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This paper formulates a general framework that includes and extends the existing definitions for network survivability. Based on this framework, network survivability is characterized by a survivability function rather than a single-value survivability measure, and various quantities of interest can be derived from the function. Examples are the expected survivability, the worst-case survivability, the r-percentile survivability, and the probability of zero survivability. The survivability function is especially useful for the study of large-scale disasters. For illustration, the authors derive the survivability function in closed form for a simple ring network under link failures. They also discuss the general procedure for finding survivability functions for complex networks, and show that the survivability function reveals useful information about a network. This framework provides a unified and practical approach to analyzing and designing highly survivable communications networks 相似文献
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As networks grow in size, large-scale failures caused by disasters may lead to huge data loss, especially in an optical network employing wavelength-division multiplexing (WDM). Providing 100 % protection against disasters would require massive and economically unsustainable bandwidth overprovisioning, as disasters are difficult to predict, statistically rare, and may create large-scale failures. Backup reprovisioning schemes are proposed to remedy this problem, but in case of a large-scale disaster, even the flexibility provided by backup reprovisioning may not be enough, given the sudden reduction in available network resource, i.e., resource crunch. To mitigate the adverse effects of resource crunch, an effective resource reallocation is possible by exploiting service heterogeneity, specifically degraded-service tolerance, which makes it possible to provide some level of service, e.g., reduced capacity, to connections that can tolerate degraded service, versus no service at all. Software-Defined Networking (SDN) is a promising approach to perform such dynamic changes (redistribution of network resources) as it simplifies network management via centralized control logic. By exploiting these new opportunities, we propose a Backup Reprovisioning with Partial Protection (BRPP) scheme supporting dedicated-path protection, where backup resources are reserved but not provisioned (as in shared-path protection), such that the amount of bandwidth reserved for backups as well as their routings are subject to dynamic changes, given the network state, to increase utilization. The performance of the proposed scheme is evaluated by means of SDN emulation using Mininet environment and OpenDaylight as the controller. 相似文献
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Manijeh Keshtgary A. H. Jahangir Fahad A. Al-Zahrani Anura P. Jayasumana 《Photonic Network Communications》2006,11(1):15-27
Network Survivability is defined as the ability of a network to support the committed Quality of Services (QoS) continuously
in the presence of different failure scenarios. Both availability and performance degradation of a system in presence of failure
are integral components of survivability evaluation. Therefore, a composite model is presented for network survivability that
includes system availability analysis to find out the cost due to system downtime, and system failure impact analysis to find
out the transient performance degradation when failure occurs. A new analytical technique is presented to evaluate the excess
loss due to failure (ELF) as the transient performance degradation when the system is operating in gracefully degraded states.
Single and multiple link failures as well as node failures are considered. An algorithm is proposed to carry out the steady
state availability analysis of a network even when the available paths between a pair of nodes are non-disjoint. A recursive
generalized form of the availability algorithm when there are multiple paths available between a pair of nodes is presented.
The availability model and the performance model are combined to construct a hierarchical model to evaluate the network survivability
performance. Simulation results are used to validate the proposed model. A WDM network with wavelength conversion is considered
as an example for this evaluation. 相似文献
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Providing fault tolerance in wireless access networks 总被引:2,自引:0,他引:2
Research and development on network survivability has largely focused on public switched telecommunications networks and high-speed data networks with little attention on the survivability of wireless access networks supporting cellular and PCS communications. This article discusses the effects of failures and survivability issues in PCS networks with emphasis on the unique difficulties presented by user mobility and the wireless channel environment. A simulation model to study a variety of failure scenarios on a PCS network is described, and the results show that user mobility significantly worsens network performance after failures, as disconnected users move among adjacent cells and attempt to reconnect to the network. Thus, survivability strategies must be designed to contend with spatial as well as temporal network behavior. A multilayer framework for the study of PCS network survivability is presented. Metrics for quantifying network survivability are identified at each layer. Possible survivability strategies and restoration techniques for each layer in the framework are also discussed 相似文献
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The authors present a new approach for trunk network survivability. This modular approach is intended for a telephone trunk network consisting of high-bandwidth fiber-optic links connected through reconfigurable digital cross-connect nodes. It works for both node and link failures. This approach comprises a distributed protocol with two parts. First, the surviving digital cross-connect nodes are caused to converge to an agreement on the topology (i.e., what is up and what is down). Second, based on the agreed topology and on a precomputed plan for that topology, the digital cross-connect nodes are reconfigured to restore as much call-carrying capacity as possible. The modularity of this approach comes from separating the problem of devising a distributed fault-tolerant protocol to determine what the failure is from the problem of designing a network reconfiguration for that failure 相似文献
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The Internet may get catastrophic impacts when unexpected disasters such as earthquakes, tsunami, etc. happen. Therefore, it is necessary to equip resilient technologies for the Internet backbones in order to face challenges (e.g., link, device failures, rerouting traffic, etc.) in the disasters. The emerging software-defined networking (SDN) technology, which logically centralizes network function on a controller and remotely manages distributed SDN devices, shows a lot of potential. This paper presents an experimental feasibility study on applying SDN to wide area backbones for the disaster-resilient purpose. To show the efficiency of SDN technology in responding fast to the network situation changes, we conduct three evaluations on real SDN devices and large-scale SDN-based wide area networks (WANs) assuming disaster scenarios. In the first evaluation, we explore the proactive recovery mechanism using the fast failover on SDN devices. In the second one, we investigate the communication latency between controllers and SDN devices, which is one of the most important factors in the reactive recovery in the software-defined backbone. In the last one, we experiment the fast end-to-end reactive recovery behavior of a TCP flow in a disaster scenario. The evaluation results clearly indicate that the SDN-based WAN is technically feasible and effective for fast recovery from disasters. 相似文献
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A very important issue in many network applications is to provide protection against planned failures. In this paper we first define the concept of a planned failure and then analyze the cost implications in the design of a network for survivability (i.e. protection against planned failure), as against designing a network against random failures. We suggest a simple and systematic approach for designing survivable communication networks and also discuss briefly the consequences of availability of partial knowledge only. 相似文献
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With the large-scale deployment of optical network equipments, the problems of separated domains management and the multi-domain-based survivability have become the primary challenge in new generation intelligent optical networks. Aimed at resisting multi-link failures in multi-domain optical networks (MDON), a heuristic multi-link fault-tolerant (MLFT) algorithm for survivability in MDON is proposed in this article, which applied Hamiltonian cycle protection and segment-shared protection to establish a novel survivability strategy for either intra-domain??s or inter-domain??s multiple links, respectively. Furthermore, a new virtual-link mapping scheme and link-cost formulas are presented to encourage the appropriate routing selection and load balancing, which can also contributed to better resource utilization ratio and blocking ratio. Simulation results show that MLFT realizes the multi-link fault-tolerant survivability at a lower cost with better performances in redundancy ratio, blocking ratio, and computation complexity. 相似文献
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A Novel Fast Multicast Algorithm with Enhanced Survivability in WDM Optical Networks 总被引:3,自引:1,他引:2
WDM optical networking technology is expected to facilitate bandwidth-intensive multicast application by establishing a light-tree which regards the source node as the root and all the destination nodes as the leaves. However, the existing multicast routing algorithms are time-consuming and the generated light-trees are very sensitive to failures, e.g., a single fiber cut can disrupt the information from transmitting to several terminals. In this paper, we propose a novel fast multicast algorithm with enhanced survivability (FMES), which applies a two-stage multicast routing approach, and employs a path protection scheme for each segment of the first stage tree. Analysis and experimental results show that FMES has the significant advantage of a much shorter running time than that in existing schemes, and this advantage can be enlarged in the distributed routing and signaling system of the coming intelligent optical networks. We also compare FMES with non-protection and full-protection schemes. It shows that the FMES scheme achieves the best trade-off between network survivability and resource-utilization. We illustrate our study with numerical experiments based on the real-life ChinaNet topology. 相似文献
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As virtual networks services emerge increasingly with higher requirement of flexibility and robust, great complex challenges caused by physical-layer impairments are presented to the elastic optical networks(EON). Aimed to solve this problem, this paper proposes a physical impairment awareness based virtual network mapping stragegy of EON. The physical impairments awareness model is established, including both of linear factors and nonlinear ones. On this basis, this paper proposes a virtual network mapping strategy with detailed procedures, combined with node importance factors during the virtual network mapping procedure. Test results show that the proposed approach is able to reduce blocking rate and enhance services supporting ability of EON. 相似文献