A Unified Metric for Quality of Service Quantification

Pedro Alipio1, Solange Lima2 and Paulo Carvalho2

Critical Software, S.A.1
Parque Industrial de Taveiro
P-3045-504, Coimbra, Portugal

Universidade do Minho2
Departamento de Informática
P-4710-057 Braga, Portugal

Tel.: +351 253 604436; Fax.: +351 253 604471
E-mail: pmc at di.uminho.pt

Internet service providers usually express the quality of network services through a set of values determined according to several network performance parameters periodically collected or measured. However, for common end-users, these values do not give an overall idea of the quality of the network services as they stand for different units and evaluate different perspectives of each service quality.
In this context, this paper proposes the definition of a service-oriented unified metric which quantifies a global Quality of Service (QoS) indication by processing standard QoS parameters through a fuzzy controller. The proposed methodology, based on fuzzy logic and tested on Xfuzzy 3.0 platform, allows to close the gap between a high-level QoS perspective and the effective QoS measurements at lower protocolar levels. The definition of a single per-service QoS metric can be useful to simplify control tasks such as QoS routing, SLA negotiation and auditing.
SIMUTools/QoSim 2009, Rome, Italy, March 2009