Quality of Service Specifications: A Semantic Approach

In operations related to quality of service (QoS) management such as SLA negotiations, QoS-aware service invocations and so, it is necessary to specify the required or negotiated quality parameters. Currently, there are no standards to formally describe QoS specifications at the network service level. Several works propose a fixed list of QoS parameters at the network level (e.g., delay, jitter, packet loss). However, solutions offering an extensible list of QoS parameters to specify QoS are more appropriate to deal with the heterogeneity of applications and network technologies. This paper proposes an ontology as a formal and extensible way of specifying QoS and provide the mapping between parameters of different layers. Using our ontology, clients and providers can adopt different user-perceived, application or network QoS parameters and metrics during the service negotiation and invocation, and use ontology reasoning to compare different parameters. The usage of this ontology is illustrated during the establishment of a VoIP session, where a high level QoS specification in the application layer is mapped into a network layer class of service defined by the service provider.