The Use of Enumerative Techniques in Topological Optimization of Computer Networks Subject to Fault Tolerance and Reliability

Topological optimization of computer networks is concerned with the design of a network by selecting a subset of the available set of links such that the fault tolerance and reliability aspects are maximized while a cost constraint is met. A number of enumeration-based techniques were proposed to solve this problem. They are based on enumerating all the possible paths (for Terminal reliability) and all the spanning trees (for ��Network reliability). Existing enumeration-based techniques for solving this network optimization problem ignore the fault-tolerance aspect in their solution. Fault tolerance is an important network design aspect. A fault tolerant network is able to function even in the presence of some faults in the network. In this paper, we propose one algorithm for optimizing the terminal reliability and another for optimizing the network reliability while improving the fault tolerance aspects of the designed networks. Experimental results obtained from a set of randomly generated networks using the proposed algorithms are presented and compared to those obtained using the existing techniques [1], [2]. It is shown that improving the fault tolerance of a network can be achieved while optimizing its reliability however at the expense of a reasonable increase in the overall cost of the network while remaining within a maximum pre-specified cost constraint

The Use of Enumerative Techniques in Topological Optimization of Computer Networks Subject to Fault Tolerance and Reliability

Topological optimization of computer networks is concerned with the design of a network by selecting a subset of the available set of links such that the fault tolerance and reliability aspects are maximized while a cost constraint is met. A number of enumeration-based techniques were proposed to solve this problem. They are based on enumerating all the possible paths (for Terminal reliability) and all the spanning trees (for ��Network reliability). Existing enumeration-based techniques for solving this network optimization problem ignore the fault-tolerance aspect in their solution. Fault tolerance is an important network design aspect. A fault tolerant network is able to function even in the presence of some faults in the network. In this paper, we propose one algorithm for optimizing the terminal reliability and another for optimizing the network reliability while improving the fault tolerance aspects of the designed networks. Experimental results obtained from a set of randomly generated networks using the proposed algorithms are presented and compared to those obtained using the existing techniques [1], [2]. It is shown that improving the fault tolerance of a network can be achieved while optimizing its reliability however at the expense of a reasonable increase in the overall cost of the network while remaining within a maximum pre-specified cost constraint

The Use of Enumerative Techniques in Topological Optimization of Computer Networks Subject to Fault Tolerance and Reliability

Topological optimization of computer networks is concerned with the design of a network by selecting a subset of the available set of links such that the fault tolerance and reliability aspects are maximized while a cost constraint is met. A number of enumeration-based techniques were proposed to solve this problem. They are based on enumerating all the possible paths (for Terminal reliability) and all the spanning trees (for ��Network reliability). Existing enumeration-based techniques for solving this network optimization problem ignore the fault-tolerance aspect in their solution. Fault tolerance is an important network design aspect. A fault tolerant network is able to function even in the presence of some faults in the network. In this paper, we propose one algorithm for optimizing the terminal reliability and another for optimizing the network reliability while improving the fault tolerance aspects of the designed networks. Experimental results obtained from a set of randomly generated networks using the proposed algorithms are presented and compared to those obtained using the existing techniques [1], [2]. It is shown that improving the fault tolerance of a network can be achieved while optimizing its reliability however at the expense of a reasonable increase in the overall cost of the network while remaining within a maximum pre-specified cost constraint

Reliability and fault tolerance based topological optimization of computer networks - part I: enumerative techniques

Topological optimization of computer networks is concerned with the design of a network by selecting a subset of the available set of links such that the fault tolerance and reliability aspects are maximized while a cost constraint is met. A number of enumeration-based techniques were proposed to solve this problem. They are based on enumerating all possible paths (for terminal reliability) and all the spanning trees (for network reliability). Existing enumeration-based techniques for solving this network optimization problem ignore the fault-tolerance aspect in their solution. We consider fault tolerance to be an important network design aspect In this paper, we propose one algorithm for optimizing the terminal reliability and another for optimizing the network reliability while improving the fault tolerance aspects of the designed networks. Experimental results obtained from a set of randomly generated networks using the proposed algorithms are presented and compared to those obtained using existing techniques. It is shown that improving the fault tolerance of a network can be achieved while optimizing its reliability however at the expense of a reasonable increase in the overall cost of the network

On Fault Tolerance Methods for Networks-on-Chip

Technology scaling has proceeded into dimensions in which the reliability of manufactured devices is becoming endangered. The reliability decrease is a consequence of physical limitations, relative increase of variations, and decreasing noise margins, among others. A promising solution for bringing the reliability of circuits back to a desired level is the use of design methods which introduce tolerance against possible faults in an integrated circuit. This thesis studies and presents fault tolerance methods for network-onchip (NoC) which is a design paradigm targeted for very large systems-onchip. In a NoC resources, such as processors and memories, are connected to a communication network; comparable to the Internet. Fault tolerance in such a system can be achieved at many abstraction levels. The thesis studies the origin of faults in modern technologies and explains the classification to transient, intermittent and permanent faults. A survey of fault tolerance methods is presented to demonstrate the diversity of available methods. Networks-on-chip are approached by exploring their main design choices: the selection of a topology, routing protocol, and flow control method. Fault tolerance methods for NoCs are studied at different layers of the OSI reference model. The data link layer provides a reliable communication link over a physical channel. Error control coding is an efficient fault tolerance method especially against transient faults at this abstraction level. Error control coding methods suitable for on-chip communication are studied and their implementations presented. Error control coding loses its effectiveness in the presence of intermittent and permanent faults. Therefore, other solutions against them are presented. The introduction of spare wires and split transmissions are shown to provide good tolerance against intermittent and permanent errors and their combination to error control coding is illustrated. At the network layer positioned above the data link layer, fault tolerance can be achieved with the design of fault tolerant network topologies and routing algorithms. Both of these approaches are presented in the thesis together with realizations in the both categories. The thesis concludes that an optimal fault tolerance solution contains carefully co-designed elements from different abstraction levelsSiirretty Doriast

Reliability and Fault Tolerance based Topological Optimization of Computer Networks - Part II: Iterative Techniques

Abstract-Topological optimization of computer networks is concerned with the selection of a subset of the available links such that the reliability and fault-tolerance aspects are maxhized while meeting a cost constraint. In this case. the problem is stated as opthiring the reliability and fault-tolerance of a network subject to a maximum cost constraint. Existing iterative-based techniques consider the simple single-objective version of the problem by considering reliability as the only objective We consider fault-tolerance to be an important network design "ped We consider the use of three iterative techniques, namely Tabu Search, Simulated Anenling, and Genetic Algorithm, in solving the multi-objective topological optimization network design problem. Experimental results for a set of 10 randomly generated networks using the three iterative techniques are presented and compared. It is shown that improving the fault tolerance of a network can be achieved while optimizing its reliability however at the expense of a reasonable in- m the overall cost of the network. Keywords: Topological Optimization, Fault Tolerance, Reliability, Genetic Algorithm, Tabu Search, Simulated Annealing, Spanning tree

Analysis of distributed resource management in wireless LANs that support fault tolerance

Deploying wireless LANs (WLAN) at large scale is mainly affected by reliability, availability, and performance. These parameters will be a concern for most of managers who wanted to deploy WLANs. In order to address these concerns, new radio resource management techniques with fault tolerance can be used in a new generation of wireless LAN equipment. These techniques would include distributed dynamic channel assignment, sharing load among Access Points (AP), and supporting fault tolerance. Changing from the relatively static radio resource management techniques generally in use today to dynamic methods has been addressed in previous research article using centralized management, but it suffer from network availability problem. In [10] a new distributed management for dynamic channel assignment has been suggested. In this paper the idea has been extended to support fault tolerance, which improves the network availability and reliability compared to centralized management techniques. In addition, it will help in increasing network capacities and improve its performance especially in large-scale WLANs. The new system has been analyzed and according to binomial distribution results showed improvement of network performance compared to static load distribution

Reliability and fault tolerance based topological optimization of computer networks - part II: iterative techniques

Topological optimization of computer networks is concerned with the selection of a subset of the available links such that the reliability and fault-tolerance aspects are maximized while meeting a cost constraint. In this case, the problem is stated as optimizing the reliability and fault-tolerance of a network subject to a maximum cost constraint. Existing iterative-based techniques consider the simple single-objective version of the problem by considering reliability as the only objective. We consider fault-tolerance to be an important network design aspect. We consider the use of three iterative techniques, namely tabu search, simulated annealing, and genetic algorithms, in solving the multiobjective topological optimization network design problem. Experimental results for a set of 10 randomly generated networks using the three iterative techniques are presented and compared. It is shown that improving the fault tolerance of a network can be achieved while optimizing its reliability however at the expense of a reasonable increase in the overall cost of the network

ENUMERATIVE TECHNIQUES IN TOPOLOGICAL OPTIMIZATION OF COMPUTER NETWORKS SUBJECT TO FAULT TOLERANCE AND RELIABILITY

In this paper, we propose one algorithm for optimizing the terminal reliability and another for optimizing the network reliability while improving the fault tolerance aspects of the designed networks. Experimental results obtained from a set of randomly generated networks using the proposed algorithms are presented and compared to those obtained using the existing techniques [1], [2]. It is shown that improving the fault tolerance of a network can be achieved while optimizing its reliability however at the expense of a reasonable increase in the overall cost of the network