Affiliations: School of Computing, Informatics, Decision Systems
Engineering, Arizona State University, Tempe, AZ 85287-8809, USA | U.S. Air Force Research Laboratory/RIGA, Rome, NY 13441-4505, USA
Abstract: Service quality on computer and network systems has become
increasingly important as many conventional service transactions are moved
online. Service quality of computer and network services can be measured by the
performance of the service process in throughput, delay, and so on. On a
computer and network system, competing service requests of users and associated
service activities change the state of limited system resources which in turn
affects the achieved service quality. Modeling dynamic relations of service
activities, system state and service quality is required to determine if users'
service requests and requirements of service quality can be satisfied by the
system with limited resources and how the system and service configuration can
be adapted to meet service quality requirements. This paper presents our
empirical study to establish activity-state-quality models for a voice
communication service. We run experiments to collect system dynamics data under
various service conditions and use statistical techniques to analyze
experimental data and build activity-state-quality models. The results reveal
four major types of dynamic relations among service activity parameters, system
resource state, and the network throughput – a measure of achieved service
quality for the voice communication service. Although delay-related measures
are also important for voice data communication, they are not collected in this
study. Five system state variables concerning the memory, CPU, process and IP
resources are uncovered to be affected by service activity parameters
significantly and be associated with the achieved service quality closely. We
also obtain an insight about increasing the size of the buffer which holds
voice data before transmission over the network to alleviate the workload on
system resources and maintain the network throughout when the number of client
requests and the client requirement in voice quality increase.
Keywords: Computer and network service, achieved service quality, service and system configuration, voice communication service, statistical analysis and modeling