可生存网络系统的形式化定义

随着大规模、分布式网络系统对信息安全需求的进一步提高,其安全问题的研究重点已转移为网络系统的可生存性研究.那么,首要问题是建立统一、规范的网络系统的可生存性定义.文中从网络系统的可生存需求出发,借鉴了近年来国内外的可生存研究成果,提出了规范化的网络系统的可生存性定义,并给出其形式化的描述及其实现模型,为下一阶段的系统可生存性的定量分析提供统一、规范的可生存性定义.     

生存性网络系统的构建

论文描述了生存性网络系统的需求,提出了一种生存性网络系统设计思路,并以成熟的技术构建一种基于多层次备份的可生存性网络。     

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。     

基于自主配置的系统生存性增强算法研究

在系统冗余前提下，提出动态配置原子组件来增强系统生存性方法；根据中心极限定理和系统运行历史数据，获取原子组件生存性变化曲线，并结合系统服务效率以及服务质量等，设计了基于自主配置的生存性增强算法。通过实验验证了生存性计算方法在原子组件不同失效率下的正确性和有效性。仿真实验表明，该算法在原子组件遭受攻击和服务能力下降情况下都能有效保证关键服务的生存性。     

电子政务系统的可生存性策略研究

网络系统可生存性是对传统网络安全观念的突破和创新,是综合网络系统安全性、可靠性、容错性等领域研究成果的新方向。在网络攻击不可避免、安全防御机制失效的情况下,如何能保证电子政务系统的可生存性是当前研究的重点。通过对电子政务系统网络特点与安全威胁的分析,并在对可生存性网络信息系统的一般模型分析的基础上,提出了电子政务系统安全可生存性模型。该模型主要针对电子政务的外网、专网、内网3个层次进行了安全对策的研究分析。     

Ad Hoc网络的可生存性研究

对Ad Hoc网络的可生存性问题进行了阐述和分析,说明了A d Hoc网络可生存性面临的问题和挑战,特别强调了军事需求。从三个方面探讨了A d Hoc网络的可生存性问题:可生存的网络连接、可生存的通信及可生存性技术,尤其对可生存性技术进行了较全面的剖析。     

ad hoc网络的可生存性问题及设计挑战

本文介绍了ad hoc网络可生存性面临的问题和挑战,特别强调了军事需求.其中从三个方面探讨了ad hoc网络的可生存性问题:可生存的网络连接、可生存的通信服务及可生存性技术,尤其是对可生存性技术进行了较全面的剖析.     

可生存光网络中的不同QoS策略

随着光网络技术的不断发展,网络的生存性及其QoS问题越来越受到关注.文章围绕可生存光网络中的不同QoS策略这一问题,首先介绍了可生存光网络及其QoS参数的概念,解释了为什么如今要考虑可生存光网络中的不同QoS策略.接着以传统光网络生存性方法的一般分类图为依据,从原理、性能等方面归纳比较了以往各种生存性方法,并分析了各自的优缺点.最后根据考虑可生存性光网络中QoS参数的不同,具体描述了用来支持不同业务的各种光网络生存性方法.     

一种MANET可生存性模型的建模方法

文中提出了一种针对移动Ad hoc网络可生存性模型的建模方法,构建MARC（MANET Actor,Role and Coordinator Model）可生存性描述模型,并且支持利用该方法构建的可生存性模型向仿真实例的自动转换。详细分析并形式化描述了MARC模型中涉及的网络服务和事件等概念,并以此为基础设计了可生存性模型描述语言MARCDL,列举了语言中主要的EBNF范式描述。实例分析表明,运用该建模方法,不仅可以抽象地构造出面向战术环境的移动Ad hoc网络可生存性模型,而且为可生存性模型的从高层描述到低层仿真的自动转换提供了有力支持。     

可生存性控制系统的有限状态机的设计

文章提出一种基于布尔表达式的可生存性控制系统的有限状态机的设计方法。基于系统服务、节点功能和故障元素之间的布尔函数关系．给出可生存性控制系统的有限状态机的形式化规范，并自动满足受控系统的可生存性。     

Integrity of public telecommunications networks

Provides an overview of the special issue of the IEEE Journal of Communications, Volume 12, Number 1 (January 1994) which addresses open questions in network integrity, reliability and survivability. Current progress in this area is discussed. The questions addressed include user survivability perspectives on standards, planning, and deployment; the analysis and quantification of network disasters; survivable and fault-tolerant network architectures and associated economic analyses; and techniques to handle network restoration as a result of physical damage or failures in software and control systems. Special interests are devoted to the survivability of broadband networks employing the new transport/switching techniques based on the synchronous optical network (SONET) and asynchronous transfer mode (ATM) standards due to their emerging role in future B-ISDN. Network integrity due to failures of common channel signaling (CCS) systems is also very critical. The present special issue includes 22 papers and is organized into the following sections: user perspectives and planning, software quality and reliability, network survivability characterization and standards, network restoration for SONET networks, network restoration for ATM networks, traffic effect and performance enhancement for computer networks, and survivable network design methods. Network restoration methods for SONET, ATM, and computer networks correspond to those for the physical layer (SONET), ATM layer, and the network layer, defined in the CCITT broadband ISDN layer structure     

Emerging technologies for fiber network survivability

Reducing network protection costs, while maintaining an acceptable level of survivability, has become an important challenge for network planners and engineers. This article will review technology and architectures that may be used to implement cost effective survivable fiber networks for each transport layer, and discuss the interworking system between survivability mechanisms across different layers and associated open issues. Standards development, product availability and the current status of deployment will also be reviewed. The first section reviews a class of survivable fiber network architectures that has been deployed or is scheduled to be deployed. Next is a review of emerging technologies for these survivable architecture implementations. These emerging technologies include SONET, ATM, and passive optical technology. Finally the issue of multiple layer interworking on SONET/ATM networks is discussed     

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。     

A novel domain-by-domain survivable mechanism in multi-domain wavelength-division-multiplexing optical networks

In multi-domain wavelength-division-multiplexing (WDM) optical networks, the inter-domain routing is a challenge since each single-domain cannot view the full network topology. At the same time, survivability is also an important issue in optical networks since the failures of fiber links or network nodes may lead to a lot of traffic being blocked. In this paper, we study the survivability in multi-domain WDM optical networks, and propose a new survivable mechanism called load balanced domain-by-domain routing (LBDDR). In LBDDR, in order to obtain the efficient inter-domain survivable routes, we present the domain-by-domain routing (DDR) method which can find the intra-domain sub-working path and sub-backup path in each single-domain to form the inter-domain working path and backup path for each demand. In order to reduce the blocking probability, we present the load balanced routing method which can encourage the traffic to be uniformly distributed on the links with more free wavelengths. Simulation results show that, compared with conventional mechanism, LBDDR can obtain better performances.     

Selective survivability with disjoint nodes and disjoint lightpaths for layer 1 VPN

This paper deals with the problem of survivable routing and wavelength assignment in layer 1 virtual private networks (VPNs). The main idea is routing the selected lightpaths by the layer 1 VPN customer, in a link-disjoint manner. The customer may freely identify some sites or some connections, and have their related lightpaths routed through link-disjoint paths through the provider’s network. This selective survivability idea creates a new perspective for survivable routing, by giving the customer the flexibility of selecting important elements (nodes or connections) in its network. This study is different from previous studies which aim to solve the survivable routing problem for the whole VPN topology. The proposed scheme is two-fold: disjoint node based, and disjoint lightpath based. In disjoint node scheme, all lightpaths incident to a node are routed mutually through link-disjoint paths. In disjoint lightpath scheme, a lightpath is routed in a link-disjoint manner from all other ligthpaths of the VPN. We present a simple heuristic algorithm for selective survivability routing. We study the performance of this algorithm in terms of resources allocated by the selective survivability routing scheme compared to shortest path routing with no survivability. The numerical examples show that the amount of used resources by the selective survivability scheme is only slightly more than the amount used in shortest path routing, and this increase is linear. The extra resources used by the new scheme are justified by better survivability of the VPN topology in case of physical link failures, and the simplicity of the implementation.     

Multi-Layer Differentiated Integrated Survivability for Optical Internet

In this paper, we study the problem of multi-layer integrated survivability (MLIS) for efficiently provisioning reliable traffic connections of arbitrary bandwidth granularities in the integrated optical Internet. We decompose the MLIS problem into three sub-problems: survivable strategies design (SSD), spare capacity dimensioning (SCD), and dynamic survivable routing (DSR). First, a review of network survivability in multi-layer IP/WDM networks is provided. Then, multi-layer survivability strategies are proposed and it is observed how these strategies could be applied to the integrated optical Internet architecture. We also present an enhanced integrated shared pool (ISP) method for solving the static MLIS problem (i.e., the SCD sub-problem) and the priority-based integer programming formulations are also given. Moreover, we design a novel scheme called the differentiated integrated survivability algorithm (DISA) to solve the dynamic MLIS problem (i.e., the DSR sub-problem), which employs flexible survivable routing strategies according to the priority of the traffic resilience request. Performance simulation results of DISA show that our adaptive survival schemes perform much better in terms of traffic blocking ratio, spare resource requirement, and average traffic recovery ratio compared with other solutions in the optical Internet.