Survivability evaluation towards attacked WSNs based on stochastic game and continuous-time Markov chain

Because a large number of Wireless Sensor Networks (WSNs) are deployed in unsafe surroundings, the survivability evaluation towards attacked WSNs has become a critical issue. Due to its popularity, the cluster-based structure of WSNs in this paper is selected to be studied and regarded as a serial-parallel system according to its characteristics. In order to set up the relation between the intention of attack behaviors and the randomness of continuous-time Markov chain (CTMC), we construct an attack-prediction stochastic game that is able to attain the attack probabilities adopted by the attacker in different states. Therefore, the consequence from a successful attack can be modeled as a deliberate state change of the CTMC. Upon this, the state transition matrix describing various states during the lifetime of an attacked sensor node can be formed. We are then able to compute the MTTF (Mean Time To Failure) of an attacked sensor node in perspective of CTMC. Based on the classical reliability theory, we thus propose a mechanism of survivability evaluation for attacked WSNs, which is composed of the reliability, survival lifetime, and availability in the steady state. Our experiments show the influence degree of the game parameters to the expected motivation of the attacker as well as disclose the relation between the MTTF of an attacked sensor node and the expected motivation of the attacker. In addition, the effectiveness of our survivability evaluation metrics is validated. These results will be able to build up the theoretical foundation to guide the design of highly survival WSNs.     

基于ESB的信息交换系统可靠性仿真与分析

基于ESB的信息交换系统可靠性和生存能力分析,对提高整个系统的安全运行水平具有重要作用.可靠性是系统生存能力评估的重要指标,其建模分析一直是系统生存能力评估的难点.为了有效分析基于ESB信息交换系统的可靠性,把信息交换系统建模为串联可修复系统,提出一种概率分析方法对该模型的可靠度和瞬时可用度进行定量分析及比较.仿真结果表明,在给定部件的故障率和修复率等先验概率时,ESB信息交换系统遭受病毒攻击所产生的故障是系统可靠度及瞬时可用度下降的主要原因,修复率对瞬时可用度的提高具有重要作用,运营单位应设法提高系统修复率和抗攻击的能力.     

Survivable ATM mesh networks: Techniques and performance evaluation

The Capacity and Flow Assignment problem in self-healing ATM networks is an interesting one from a Generalized Multi-Protocol Label Switching (GMPLS) prospective since IP and ATM protocols are destined to co-exist together in this unified platform. This paper continues the investigation of the path-based design approach of the network survivability problem in existing ATM mesh networks. Our contribution consists in quantifying (1) the effects the selection of candidate paths per node pair has on the restoration ratio, (2) the effect of restoration schemes on the restoration ratio, (3) the effect of failure scenarios on the restoration ratio, and finally (4) the effect of network connectivity on the restoration ratio. Numerical results are presented under representative network topologies, various traffic demands and spare capacity distribution schemes. They provide additional guidelines for the design of survivable ATM mesh-type networks, from a network reliability viewpoint.     

An efficient link allocation algorithm for survivable ATM-based personal communication networks

The integration of the issue of survivability of wireless networks in the design process of the backbone network is addressed in this paper. The effectiveness of this integration plays a critical role in the success of the wireless network and the satisfaction of its mobile users. In this paper, we consider the design problem of allocating the backbone links in ATM-based personal communication networks (PCNs) that are survivable under single backbone link failures. Survivability is achieved by selecting two link-disjoint routes in the backbone network between every pair of ATM switches. We also take the novel approach of not only minimizing the diameter of the network as a primary objective but also minimizing the total length of the network as a secondary objective. We propose a new heuristic algorithm to optimize the design of the network based on both objectives. We report the results of an extensive simulation study that show that our algorithm generates backbone networks that can withstand single link failures, have shorter average diameters and smaller total lengths and achieve a higher percentage of admitted calls under a mobile environment.     

信息系统的可存活性

可存活性是用来表明系统在面对蓄意攻击、故障失效或偶发事故时仍能完成其任务的能力.可存活性要求系统具有四个关键性质:抵抗性、识别性、恢复性、适应和演化性质.目前对于可存活性的研究可以分为分析和实现两个方面.可存活性的分析一般通过建模的方法,对原有系统的可存活性进行度量,找到系统的薄弱环节.可存活性的实现一般通过体系结构的设计改进或者重新配置的方法,来提高系统的可存活能力.无论是分析还是实现的研究,方法多样,但是却有着很大的局限性.     

生存光传输网络的交叉连接模块结构

基于波分复用技术的光传输网络在克服当前网络容量瓶颈的同时又面临网络生存的挑战,它必须快速、有效地恢复因网络故障而受损的工作光路。该文分析了四种基本网络恢复技术以及与之相对应的OXC节点模块结构,即:保留光纤链路方式、保留波长链路方式、保留波长路径方式以及动态波长路径方式;并从光连接恢复时间、网络资源效率和控制复杂度三个侧面比较了不同OXC结构对于网络生存的影响。     

Hop-Constrained Node Survivable Network Design: An Application to MPLS over WDM

In this paper, we address a hop-constrained node survivable network design problem that is defined in the context of multi-protocol label switching (MPLS) over wavelength division multiplexing (WDM) networks. At the lower WDM layer, we consider a maximum length constraint for optical connections between MPLS routers. At the upper MPLS layer, we consider survivability as well as maximum delay constraints. Survivability is guaranteed by routing each demand through D node-disjoint paths and maximum delay is guaranteed by constraining all paths to a maximum number of hops. An Integer Linear Programming model, based on the previous works by Gouveia et al. (Proc of IEEE INFOCOM, 2003, and Telecommunications network planning: innovations in pricing, network design and management, pp 167–180, 2006) is used to model the network design problem considering two different survivability mechanisms: path diversity (where each demand is equally split over the D paths) and path protection (where any D–1 out of the D paths have enough capacity to support the total demand). For both mechanisms, we use the NSFNet and EON real world networks to make a cost analysis of the design solutions for different values of D. In the path diversity mechanism, the results consistently show that greater values of D impose a cost penalty that is greater than the gain in the percentage of demand that is protected. In the path protection mechanism, where all traffic is totally protected, the results show that the network solutions obtained with D=3 node-disjoint paths have consistently lower costs than the network solutions obtained with D=2 node-disjoint paths. However, using values of D that are greater than 3 led to network solutions with larger costs. Supported by FCT project POCTI - ISFL - 1- 152.     

WDM环网保护方式的性能评价及设计原则

WDM环网以其灵活性、管理简单及生存性好等特点受到普遍重视。文章首先讨论了在进行WDM环网保护方式的设计中需注意的几个问题,并对目前可能有的几种WDM环保护方式作详细性能分析,并从不同得角度作了比较,从中得出了一些有益的结论。在此基础上,给出了进行WDM环网保护设计中应遵循的一些原则。所得出的结论对今后WDM环网保护方式的研究与设计都有一定的借鉴和帮助。     

基于SDH/ATM网络层间升级机制的研究

在一个分层的网络中,单一的恢复机制不可能满足宽带网络生存性的需要。如何协调SDH和ATM层之间恢复策略是一个急需解决的问题。该文提出几种可行的方案进行研究,并比较了它们的优缺点,这对如何设计一个有效的宽带可生存性网络提供了参考依据。     

网络的IP化趋势及其挑战与对策

网络的IP化是其发展的趋势,同时又面临着三大挑战：IP骨干网交换速度太慢造成网络瓶颈;IP网络不能提供适合运营要求的服务质量（QoS）;IP网络的可生存性（Survivability）问题。文章对以上三个问题进行了综述,着重阐述了解决挑战的方法与设想,并进一步给出了研究与发展的方向。最后对IP网络的发展与挑战进行了展望。