Digital telecommunication networks represent a fusion of concepts, techniques, and technologies from the fields of both communication and computing. The evaluation of such systems can likewise draw on methodologies which have evolved in both disciplines, bringing them together in a fashion that is suited to the needs of integrated services digital networks. With this aim, we discuss how quality...

The high expectations of performance and availability for wireless mobile systems has presented great challenges in the modelling and design of fault tolerant wireless systems. The proper modelling methodology to study the degradation of such systems is so-called performability modelling. In this paper, we give overview of approaches for the construction and the solution of performability model...

We propose a two-phase methodology for quantifying the performability (performance and availability) of cluster-based Internet services. In the first phase, evaluators use a fault-injection infrastructure to measure the impact of faults on the server’s performance. In the second phase, evaluators use an analytical model to combine an expected fault load with measurements from the first phase to...

This paper introduces a new benchmark tool for evaluating performance and availability (performability) of networked storage systems, specifically storage area network (SAN) that is intended for providing block-level data storage with high performance and availability. The new benchmark tool, named N-SPEK (Networked-Storage Performability Evaluation Kernel module), consists of a controller, sev...

In this paper we present a simple model that combines the failure to meet deadlines with hardware/software failures in computing the reliability of a real-time system. We define the performability as the probability of meeting deadlines by real-time tasks in the presence of hardware and software failures. Deadline driven schedules rely on worst-case task execution time. This may be necessary fo...

Over the last decade considerable effort has been put in the development of techniques to assess the performance and the dependability of computer and communication systems in an integrated way. This so-called per-formability modelling becomes especially useful when the system under study can operate partially, which is for instance the case for fault-tolerant computer systems and distributed s...

This paper develops time-based rejuvenation policies to improve the performability measures of a cluster system. Three rejuvenation policies, namely standard rejuvenation, delayed rejuvenation and mixed rejuvenation, are designed to improve the cluster’s performability under varying workload. Analytic models are built to evaluate these three policies. Since deterministic transitions are used in...

ed framework for the performability evaluation of fault-tolerant computer systems," IEEE Transac

The performability of a system is usually evaluated as the mean of a performance measure, aggregated over all failure scenarios (both tolerated and not) through a Markov reward process. This metric can gloss over performance deficiencies in important portions of the failure scenario space, and is also expensive to compute because the number of possible failure scenarios can be very large. We ar...