网络可生存性及其度量方法

说明了网络可生存性的概念,对传统有线和无线网络、军事网络和Ad Hoc网络的可生存性问题进行了阐述和比较分析;探讨了网络可生存性的分类和度量方法,并给出了一种度量Ad Hoc网络可生存性的方法;并指出了今后的工作方向.     

IP／MPLS-over—WDM的网络生存性

Internet的发展和数据业务的爆炸性增长对当前网络提出了更高的要求。网络将演变为IP，MPLS-over—WDM。对于这种以光网络为基础的网络构架，网络的生存性问题变得尤为重要。本文首先介绍了MPLS网络的生存性机制。由于以数据业务为中心的光网络至少包含IP层和光层，本文提出了几个在多层网络生存性面临的问题，并给出了几种方案。最后，讨论了IP／MPLS-over-WDM特有的生存性思考。     

SDH自愈环生存性定量分析

本文首先提出了网络生存性指标的概念,并对基于SDH自愈环拓扑结构的网络在灾害条件下的网络生存性进行了定量研究.文中分析了不同的业务分布条件对网络生存性指标的影响,以及灾害强度和网络生存性的关系.     

IP over DWDM网络的生存性研究

探讨了IP over DWDM生存性的机制，研究了各个网络层的恢复特点以及不同层间相互作用对生存性的影响，明确了多层网络生存性的优点，从而得出光层能够提供最快的保护，较高的层能够提供智能恢复。最后提出了一种在光层的自动保护倒换的结构，这种保护能够优先考虑来自较高层的告警信息，使IP over DWDM网络做到智能化的快速恢复，为IP over DWDM网络的研究和建设提供了一定基础。     

Ad Hoc网络的可生存性技术研究

本文首先介绍了网络可生存性的概念，阐述了Ad Hoc网络可生存性的特殊性及其面临的问题和挑战。并对适合Ad Hoc网络的可生存性技术进行了全面剖析，指出了今后的工作方向。     

基于SDN的FiWi网络生存性研究

为提高FiWi网络的生存性,将软件定义网络(SDN)技术引入到FiWi网络中,提出了一种新型生存性控制方案。详细介绍了基于SDN的FiWi网络结构,描述了新架构中不同故障级别的生存性策略,并进行了实验仿真和结果分析。     

WDM光网及多层网络生存性的研究

为了适应多层次网络发展的需要，在讨论WDM光层生存性机制的基础上，针对多层网络联合的生存性机制进行了仔细的分析，提出了一种多层协调的实现办法，并讨论了多层空闲资源设计中的共享问题。     

可生存性及紧急算法分析

主要就无边界网络系统的可生存性问题及其解决方案——紧急算法两个方面进行了分析。首先给出了作为网络信息系统发展方向的无边界系统的定义，分析其特征并引出无边界系统环境下的网络安全研究；然后提出满足安全新需求的无边界网络可生存性问题，分析了可生存性必须具备的特征及其与传统安全概念的区别，并简要分析了可生存系统的设计需求；最后着重分析了可以解决无边界网络可生存性问题的紧急算法的特征，给出了紧急算法的两种不同的定义描述，并对比分析了与传统分布式算法的不同。     

智能光网络中基于DRS的多层生存性策略的研究

近年来,基于区分生存性业务(DRS)的多层生存性问题在智能光网络生存性技术的研究中愈发受到关注.本文在分析现有多层生存性机制存在问题的基础上,结合DRS模型,设计了一种基于DRS的多层生存性策略,并对层间协调机制中的关键问题进行了研究.该策略不仅考虑了业务的可靠性需求差异,而且平衡了网络资源分配,有重要的实际应用价值.     

基于网络连接和服务的Ad Hoc网络可生存性问题研究

Ad Hoc网络是一种有着广泛应用场合的移动多跳无线网络,特别适合于战术通信和应急通信,其生存性问题备受关注。首先,阐述了Ad Hoc网络可生存性问题的特殊性和面临的挑战。然后,主要从两个方面深入探讨和分析了Ad Hoc网络的可生存性问题:网络连接的可生存性和通信服务的可生存性。最后,进行了总结并指出了今后的工作方向。     

网络生存性的测度

基于对现有生存性测度方法优缺点的考虑,提出了以网络在整个破坏过程中的网络连通度的估计为基础的一种新的基于网络拓扑结构的生存性测度方法。结合实例,给出了在节点失效、链路失效和节点链路混合失效3种失效模型下网络生存性定量分析方法和优化方法。从实例分析中容易看出,文中所提出的分析、优化方法是评估网络生存性和设计高生存性网络的一种相对简单而有效的方法。     

Data-centric optical networks and their survivability

The explosive growth of data traffic-for example, due to the popularity of the Internet-poses important emerging network requirements on today's telecommunication networks. This paper describes how core networks will evolve to optical transport networks (OTNs), which are optimized for the transport of data traffic, resulting in an IP-directly-over-OTN paradigm. Special attention is paid to the survivability of such data-centric optical networks. This becomes increasingly crucial since more and more traffic is multiplexed onto a single fiber (e.g., 160×10 Gb/s), implying that a single cable cut can affect incredible large traffic volumes. In particular, this paper is tackling multilayer survivability problems, since a data-centric optical network consists of at least an IP and optical layer. In practice, this means that the questions "in which layer or layers should survivability be provided?" and "if multiple layers are chosen for this purpose, then how should this functionality in these layers be coordinated?" have to be answered. In addition to a theoretical study, some case studies are presented in order to illustrate the relevance of the described issues and to help in strategic planning decisions. Two case studies are studying the problem from a capacity viewpoint. Another case study presents simulations from a timing/throughput performance viewpoint     

A framework for characterizing disaster-based network survivability

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     

Survivability and scalability of space networks: a survey

Survivability and scalability are key terms for any network. The challenge is greater in space networks than in terrestrial networks. Satellites have various uses, some notable uses are communication, observation, meteorology, navigation etc. In future satellites will aid terrestrial users by providing Internet connectivity. With proliferation of Internet users, demand for satellite services will increase and soon we will suffer from bandwidth limitation. Hence, the scalability and survivability of space networks are very important issues to ensure smooth connectivity to all the users both mobile and immobile. Since, most of the existing works on network survivability and scalability are focused on terrestrial networks. We have categorized the existing works on survivability and scalability of terrestrial networks. In addition, we have performed a comprehensive survey on the popular products available in the market for network survivability and scalability. Finally, we have listed the major issues and challenges of space networks that needs to be considered before applying network scalability and survivability solutions on them. This work can help network engineers to select suitable solutions for space networks considering the available choices and challenges listed in this paper.     

多层传送网的生存性策略

传送网的发展对网络的生存性提出了许多新的挑战。本文在分析了目前电信传送网的发展趋势的基础上,针对传统的网络生存性研究中存在的问题,着重研究和探讨了多层传送网中生存性面临的主要问题,提出了相应的解决策略。     

Unavailability analysis of long-haul networks

Network survivability is a key concern in today's network, and will become increasingly important in future optical networks as they carry ever more traffic. Networks are also becoming more complex, with the requirement for increased functionality. Currently, there is a lack of understanding in the industry as to the exact relationship between the choice of network architecture and the meeting of a set availability objective. This paper analyses a number of long-haul network architectures from an unavailability point of view. The long-haul networks analyzed include: networks with diversity, networks with restoration capability, and networks with survivability. Derivations are given for each architecture; formulas for 2 and 4-fiber rings, and dual fed routing are new. A hypothetical reference connection (HRX) and its unavailability objectives are used as references. Networks with restoration capability and networks with survivability meet the proposed objective. Self-healing rings (both 2 and 4-fiber bidirectional line switched rings) and dual fed systems offer the highest level of survivability, by eliminating service impacts caused by cable cuts and equipment failures     

一种高生存性的光接入网结构

提出了一种新的双环加星型环的高生存性光接入网拓扑结构,并和现行各种光接入网拓扑结构的生存性进行了定量比较.在多故障情况下,具有比现行各种光接入网结构更高的生存率.随着故障数目的增加,其网络生存率均值下降缓慢,当故障数为6时,依然可以保持99.997%的高生存率均值,大大好于现行光接入网结构,说明该接入网结构能更好地满足用户对下一代光接入网生存性的要求.     

Survivable deployment of cloud-integrated fiber-wireless networks against multi-fiber failure

Cloud-integrated fiber-wireless (FiWi) networks inheriting advantages of optical and wireless access networks have a broad prospect in the future. As various component failures may occur in cloud-integrated FiWi networks, survivability is becoming one of the key important issues. It is necessary to provide survivability strategies for cloud-integrated FiWi networks. Hence, this paper mainly focuses on the survivability of cloud-integrated FiWi networks against multiple fibers failure. Firstly, in this paper, a novel integer linear programming (ILP) solution is proposed to tolerate the failure of multiple distribution fibers with capacity and coverage constraints in the context of urban area. Then, considering the complexity of ILP models, an efficient heuristic scheme is proposed, in order to get the approximate solutions of ILP. Simulation results and analysis give the configurations of optical network units (ONUs) and wireless routers with different constraints and show the network coverage of clients for different number of ONUs and wireless routers with ILP solution and heuristic approach, respectively.     

Resource allocation strategies for survivability in WDM optical networks

WDM optical networks are high speed networks and provide enormous capacity. Survivability is very important issue in these networks. Survivability requires resources for handling the failures. So, efficient resource allocation strategy is required for survivability. In this paper, we have presented two resource allocation strategies for survivability. These strategies reserve the resources for the primary lightpaths and backup lightpaths. Then extensive simulations are done on different networks to evaluate the performance in terms of blocking probability. The results show that the second strategy performs better than first strategy.