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PERFORMABILITY EVALUATION: TECHNIQUES AND TOOLS

IP.com Disclosure Number: IPCOM000128494D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Sep-16

Publishing Venue

Software Patent Institute

Related People

Meyer, John F.: AUTHOR [+3]

Abstract

Integrated services digital networks have a number of characteristics which complicate their evaluation. In particular, since they are likely to exhibit degradable performance, the concept of performability can provide more refined assessments of their ability to perform under fault and error conditions. This paper reviews the foundations of model- based performability evaluation, and discusses various techniques and tools which have been developed for this purpose.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

PERFORMABILITY EVALUATION: TECHNIQUES AND TOOLS

1 John F. Meyer

THE UNIVERSITY OF MICHIGAN COMPUTING RESEARCH LABORATORY CRL-13-87

May 1987

Room 2222, EECS Building
Ann Arbor, Michigan 48109-2122
USA
Telephone: (313)763-8000

Performability Evaluation: Techniques and Tools
J. F. Meyer

Computing Research Laboratory

Electrical Engineering and Computer Science Department The University of Michigan
Ann Arbor, MI 48109, USA

Abstract

Integrated services digital networks have a number of characteristics which complicate their evaluation. In particular, since they are likely to exhibit degradable performance, the concept of performability can provide more refined assessments of their ability to perform under fault and error conditions. This paper reviews the foundations of model- based performability evaluation, and discusses various techniques and tools which have been developed for this purpose.

[ Chapter ] 1 Introduction

Integrated services digital networks (ISDNs) are representative of a growing class of distributed real-time systems which present new and challenging evaluation problems. As compared to systems of a more centralized and dedicated nature, one of the complicating factors is greater diversity in the services demanded from the system. This increases the complexity of workload (traffic) conditions and, in the case of model-based evaluations, the difficulties encountered in workload modeling. Specifically, when contrasting the evaluation needs of ISDNs with those of conventional telephone networks, this may be a dominating factor.

Other complications are due to the physical distribution of processing resources and to real-time constraints on system performance. These typically result in high degrees of parallelism and in requirements on the times that certain processes can be initiated or completed. Because of

1 This work is to appear in Proceedings of the International Teletraffic Congress Seminar on Traffic Engineering for ISDN Design and Planning, Lake Como, Italy, May, 1987. Published by North Holland.

University of Michigan Computing Research Laboratory Page 1 May 01, 1987

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PERFORMABILITY EVALUATION: TECHNIQUES AND TOOLS

requirements concerning dependability (i.e., reliability or availability; see2 as well as performance, such systems frequently employ fault tolerance techniques which further complicate the evaluation process. Finally, due to a combination of these factors, system performance is typically "degradable", i.e., between the extremes of nondegraded performance and failure, the system can perform at intermediate levels which provide varying degrees of benefit to the user. Generally, when evaluating a system, one seeks to relate and quantify aspects of what the system is and does with respect to what the system is required to be and do. Moreover, since what a system does (e.g., how well it performs) depends on what it is (e.g., how its...