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       Library of Congress Cataloging-in-Publication Data

      ISBN 978-1-119-62058-7

      Cover image: Pixabay.Com

      Cover design by Russell Richardson

      Series Editor Preface

      The Figure given below represents the concept of performability as introduced by the editor in 2005 and reflects a holistic view of designing, producing, using, and disposing products, systems or services, which will satisfy not only the basic operational requirements to the best possible extent with minimum cost, but are also sustainable. Sustainability aspect of products, systems and services includes that they consume minimum material and energy in their production, use and disposal and produce minimum waste in order to create minimum environmental impact which is of prime importance and requirement in the 21st Century. In other words, it should represent the holistic performance.

      In fact, the concept of performability and sustainable development are closely interlinked. To promote the concept to wider section of engineering community, consisting of planners, designers, manufacturers, researchers, technologists and users, the Editor published the first book on performability engineering in 2008 [1]. The book consisted of 76 chapters with 100 contributors and touching on all aspects of performability with the Editor himself contributing 15 chapters. The response to this book has been overwhelming with more than 495,445 chapter downloads to the end of 2019. A German company, ResearchGate, which keeps track of chapters, books etc., read by people the world over, reports that the main chapters authored by the Editor himself had the following statistics as of June 04, 2020:

Title of the Chapter	Chapter #	Total Reads
Quality Engineering and Management, pp. 157-170.	Chapter 12	18813
Reliability Engineering: A Perspective, pp. 253-288.	Chapter 19	8324
Risk Analysis and Management: An Introduction, pp. 661-674. (Safety)	Chapter 41	1602
Maintenance Engineering and Maintainability: An Introduction, pp. 747-764.	Chapter 46	7477
Sustainability: Motivation and Pathways for Implementation, pp. 835-848.	Chapter 51	377

      This indicates the interest evinced by readers the world over in the subject of performability engineering. Encouraged by this interest, Scrivener Publishing LLC undertook the publication of a series of books in the area of performability engineering with Prof. Krishna B. Misra and Prof. John Andrews of Nottingham University, UK as Series Editors in 2014, and it is matter of satisfaction that as many as 10 books have been published under this series so far. The books published under this series have solicited good number of citations in spite of the fact that much time has not elapsed after their publication.

As an Editor of this series, I solicit manuscript of books from academicians, engineers and researchers in any area of Performability Engineering. For details, please contact the Series Editor.

       Krishna B. Misra, Series Editor

       [email protected]

      Web: www.ramsconsutants.org

      June 2020

      1 [1] Misra, Krishna B. (Editor), Handbook of Performability Engineering, Springer, London, 2008.

      Preface

      Network reliability evaluation for complex communication networks is a time-consuming task. Complex networks such as computer communication networks, telecommunication networks, transport networks, etc. are an integral part of our daily life. Complex networks interconnect multiple processing units in distributed systems. Performance of such networks can be measured by evaluating the reliability index, which represents the probability that the network operates satisfactorily for a given period of time when used under stated operating conditions. A network designer has to choose suitable fault-tolerant and highly reliable network architecture to avoid performance degradation and carry out multiple communication tasks concurrently.

      Parallel computers with multiple processors have emerged to meet energy-efficient performance demands of current and future challenging computing applications. These multiprocessor systems need interconnection networks for connecting processors and memory modules. Advances in parallel and distributed computing have made interconnection networks a potential networking alternative to meet the growing demands of high-performance computing applications. These networks need to perform continuously without repair for long periods of time. Therefore, these need to be reliable and fault-tolerant as these networks are quite complex and big in size. Failure of its components should not lead to complete network failure as it may be catastrophic.

      The main objective of this book is to device approaches for reliability modeling and evaluation of such complex networks. Such evaluation helps to understand which network can give us better reliability by their design. New designs of fault-tolerant interconnection network layouts are proposed, which are capable of providing high reliability through path redundancy and fault tolerance through reduction of common elements in paths. This book covers the reliability evaluation of various network topologies considering multiple reliability performance parameters (two terminal reliability, broadcast reliability, all terminal reliability, and multiple sources to multiple destinations reliability).

For decades, work on network reliability evaluation has been going on. Our S.C. School of Quality and Reliability, earlier known as Reliability Engineering Centre, has significantly contributed to this area of research during the 1980s and onwards. The school has been involved in developing models for reliability evaluation of complex networks but static and ad hoc. The authors of this paper have significant contributions in this area.

      Interconnection networks pose another challenge to reliability evaluation due to their complex and large architectures. There are very few in this area. This subject matter has not been much addressed in easy-to-follow book materials. This book tries to bring the aspects of latest research conducted at S.C. School of Quality and Reliability to have better reach to audiences. This is the first edition of the book, so there are many improvements possible. The authors can be provided with feedback to improve the contents of the book in the possible next edition.

      This book first introduces