Survivability evaluation for networks carrying complex traffic flows

The capability of a system to fulfill its mission promptly in the presence of attacks,failures,or accidents is one of the qualitative definitions of survivability.In this paper,we propose a model for survivability quantification,which is acceptable for networks carrying complex traffic flows.Complex network traffic is considered as general multi-rate,heterogeneous traffic,where the individual bandwidth demands may aggregate in complex,nonlinear ways.Blocking probability is the chosen measure for survivability analysis.We study an arbitrary topology and some other known topologies for the network.Independent and dependent failure scenarios as well as deterministic and random traffic models are investigated.Finally,we provide survivability evaluation results for different network configurations.The results show that by using about 50%of the link capacity in networks with a relatively high number of links,the blocking probability remains near zero in the case of a limited number of failures.

Chain-type wireless sensor network node scheduling strategy

In order to reduce power consumption of sensor nodes and extend network survival time in the wireless sensor network （WSN）, sensor nodes are scheduled in an active or dormant mode. A chain-type WSN is fundamental y different from other types of WSNs, in which the sensor nodes are deployed along elongated geographic areas and form a chain-type network topo-logy structure. This paper investigates the node scheduling prob-lem in the chain-type WSN. Firstly, a node dormant scheduling mode is analyzed theoretical y from geographic coverage, and then three neighboring nodes scheduling criteria are proposed. Sec-ondly, a hybrid coverage scheduling algorithm and dead areas are presented. Final y, node scheduling in mine tunnel WSN with uniform deployment （UD）, non-uniform deployment （NUD） and op-timal distribution point spacing （ODS） is simulated. The results show that the node scheduling with UD and NUD, especial y NUD, can effectively extend the network survival time. Therefore, a strat-egy of adding a few mobile nodes which activate the network in dead areas is proposed, which can further extend the network survival time by balancing the energy consumption of nodes.

A Novel Situation Assessment Method for Network Survivability

Survivability has emerged as a new phase for the development of network security technique, and quantifying survivability for network system helps to evaluate it exactly for the system in different environments. In this paper, we adopt a stochastic method called sequential Monte Carlo and try to reflect dynamic evolvement process of network survivability situation from several time sequences. The experiment results show that this method has the features of quantitative description, real-time calculation and dynamic tracking, and it is a good situation assessment solution for network survivability.

Security,Controllability,Manageability and Survivability in Trustworthy Network

The Internet plays increasingly important roles in everyone's life; however, the existence of a mismatch between the basic architectural idea beneath the Internet and the emerging requirements for it is becoming more and more obvious. Although the Internet community came up with a consensus that the future network should be trustworthy, the concept of 'trustworthy networks' and the ways leading us to a trustworthy network are not yet clear. This research insists that the security, controllability, manageability, and survivability should be basic properties of a trustworthy network. The key ideas and techniques involved in these properties are studied, and recent developments and progresses are surveyed. At the same time, the technical trends and challenges are briefly discussed. The network trustworthiness could and should be eventually achieved.

A New Selection Criterion of Loop-free Alternate Interface for IP Fast Rerouting

As the technology of IP Fast Rerouting (FRR) become mature and the related methods and specifi cation such as RFC5286 accepted as standard, it is expected that IP FRR will be deployed gradually and will enhance the survivability of IP network. This paper presents a different method for computing the Loop-free Alternate Interfaces. The new algorithm can be referred as "Next-Hop Cost Decrease (NHCD)" criterion. Compared with the RFC5286 LFA method, NHCD can handle both the simultaneous link failure and node failure, including multi-link failures. It has less computational complexity and can be used uniformly in the Traffi c Engineering and Network Recovery. However, NHCD is somewhat lower than the LFA method on recovery ratio of single link failure. After a formal description of NHCD criterion and a proof of loopfree alternates, the paper presents the simulation results of NHCD.

Backtracking Routing Mechanism for Improving Link Failure Recovery

Failure-insensitive routing is a good mechanism to avoid packet dropping and disconnection of forwarding when some links fail, but multiple failure links may bring routing loop for the mechanism. Backtracking routing algorithm based on inverse shortest path tree rooted at destination is presented. The feasible restoration routing is obtained through searching from the start of the failure link and tracing back to the leaves of the shortest path tree with the destination as the root. The packets are forwarded from the mounted point with smaller sequence to the mount point with bigger sequence to decrease the possible of loop in case of multi-failures. The simulations and analysis indicate that backtracking routing algorithm improves the network survivability especially for large network, at the cost of the computation complexity in the same order as failure insensitive routing.

A Novel Formal Analysis Method of Network Survivability Based on Stochastic Process Algebra

Stochastic process algebras have been proposed as compositional specification formalisms for performance models. A formal analysis method of survivable network was proposed based on stochastic process algebra, which incorporates formal modeling into performance analysis perfectly, and then various performance parameters of survivable network can be simultaneously obtained after formal modeling. The formal description with process expression to the survivable network system was carried out based on the simply introduced syntax and operational semantics of stochastic process algebra. Then PEPA workbench tool was used to obtain the probability of system’s steady state availability and transient state availability. Simulation experiments show the effectiveness and feasibility of the developed method.

Dynamic recovery for survivable virtual network embedding

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.

Integrated VP-Based Control Strategies for ATM Survivable Networks

Nowadays the self-healing techniques in ATM networks are highly considered. However, in mostof networks, the normal control and sell-healing control are separately considered. In this paper, intenttedATM VP-based control strategies for ATM survivable networks are prOPosed, which combine the normalcontrol and self-healing control in a unified wad, being able to operate under both normal conditions andcatastrophic failure situations. These strategies allow a cost-effective network plan and design.

Allocation of Network Error Correction Flow on Disjoint Paths

The diversity provided by disjoint paths can increase the survivability of communication networks. This paper considers the allocation of network error correction flow on a network that consists of disjoint paths from the source node to the destination node. Specifically, we propose an algorithm of allocating the path-flows to support the given rate with minimum cost. Our analysis shows that the asymptotic time complexity of this algorithm is linearithmic, and this algorithm is optimal in general

Study of network survivability based on multi-path routing mechanism

As an important secure routing mechanism, multi-path routing is one of the major ways to improve network efficiency and to guarantee the network security, which ensures the reliability of data transmission by using backup paths when the primary one is unavailable due to local node or link failures. Most current studies on multi-path routing mechanism are based on experiments or simulations. The resulta are usually specific application scenarios oriented heuristic algorithms, lacking universal significance. In this paper, a theoretic analysis is performed on the relationship between the multi-path routing policy, the network efficiency and its survivability. Starting with point-to-point communication network, an impactoriented analysis is made on the network interference under multi-path routing mechanism. Based on the analysis, the upper-limit of network performance under interference impact is also discussed.