Suresh Rai

On computer communication network reliability under program execution constraints

The authors propose a technique to compute software system reliability (SSR). The method, called FARE (fast algorithm for reliability evaluation), does not require a priori knowledge of multiterminal connections (MCs) for computing the reliability expression. An effort is made to sole the problem of N-version programming by using the FARE approach. Owing to its short execution time and low memory requirement, FARE can be used to calculate the SSR of fairly large distributed systems. >

Computing terminal reliability of computer network

Abstract This paper discusses a technique for determination of the computer network reliability. The method utilizes the concepts of Boolean algebra and graph theory. It starts with the system success determinant obtained from the connection matrix and expands it using the simple rules defined in the text. The method does not require knowledge of either path set or cut set. It is recursive, straighforward and lacks computational complexity. An example illustrates the method.

Two Recursive Algorithms for Computing the Reliability of k-out-of-n Systems

The paper presents two recursive methods to compute reliability of a k-out-of-n system. The method is simple and computationally efficient when compared with other current methods. Examples illustrate the technique. The algorithms are presented in a recursive language with an Algol-like notation. The algorithms are easy to remember and can be used for manual computations.

Recursive Technique For Computing System Reliability

This paper presents a simple recursive formula for calculating source-to-sink congestion, and hence reliability, in a network. This congestion is derived from individual blocking probabilities of each link. The method has an advantage of not requiring cut-sets. Such a knowledge is a prerequisite in most other methods of reliability analysis. We have programmed the algorithm using Pascal as it allows recursive procedure calls. An example illustrates the method.

Reliability evaluation algorithms for distributed systems

The authors introduce two techniques for computing the reliability of a distributed computing system (DCS). The first scheme uses two steps and requires enumeration of multiterminal connections which, in turn, leads to the reliability expression. The second technique, called FARE (Fast Algorithm for Reliability Evaluation), does not require an a priori knowledge of multiterminal connections for computing the reliability expression. A performance parameter called the communication cost index (CCI) is defined. The authors compare algorithms with an existing method in terms of computer time and memory requirement. The results show that FARE outperforms two-step methods.<<ETX>>

Computing the performance index of a computer network

Abstract This paper presents a simple method for obtaining the performance index of a computer network. This index is defined as the weighted reliability where the capacity of a link is integrated with its probability of being good. The method is simple and utilizes the concept of s-t terminal reliability evaluation. An example is given to illustrate the technique.

Doubly connected multi-dimensional regular topologies for MANs and LANs

The authors present a group of multidimensional regular topologies with two incoming and two outgoing link per node. The use of a mixed-radix numbering system in defining the network topology leads to many choices for the jump distance, which provides better performance when the total number of nodes is large. They introduce a performance parameter named spanning radius (SPR) which determines the addition traversal required to use all different choices when the number of choices exceeds two. The impact of the number of choices and its SPR on the network performance is also studied. The results show that a multidimensional network performs better in terms of diameter and reliability when the penalty of the extra link traversal is offset by the saving due to the additional jump distance choices used.<<ETX>>

A comparative study of doubly connected directed topologies for LANs and MANs

This article provides an overview of doubly linked networks. We first classify the doubly linked network on the basis of the number of tuples used to represent each node address in the network. Then, each subclass of network is further partitioned into loop or nonloop categories. Various routing algorithms are studied and grouped into static or adaptive routing type, based on the number of paths between nodes used in the point-to-point message transmission. The useful protocols of the token ring and the register insertion ring and their relative advantages are also described. Some issues, such as multiple destinations routing, graceful degradation on cluster faults, and network behavior under unbalanced traffic conditions, in a doubly linked network are still open. There seems to be a need for new protocols when optical fiber is used as the medium for message transmission, which necessitates high-quality and large bandwidth data transmission.