An estimation of min-max of QoS attributes of a choreography

Several attributes of Quality of Service (QoS) of web service choreography have been proposed based on its meta model. These attributes are single valued and have been primarily used for dynamic selection and substitutivity of competing web service. It is more natural to specify the values of these attributes in terms of their minimum and maximum values either desired by the service requestor or advertised by the service provider. In this paper, we propose a methodology to estimate minimum and maximum values of attributes of QoS of a choreography. These minimum and maximum values of QoS attributes are estimated from minimum and maximum values of attributes of QoS of participating roles. These minimum and maximum value of QoS attributes for a role may be provided either by the service requestor or can be obtained from minimum and maximum values of these attributes as advertised by service provider. The QoS attributes are dominant role, dominant relationship, reliability, availability, latency and security. Our estimation model is based on trace semantics of the choreography and includes a proposal to estimate the effect of perform activity on QoS attributes of calling choreography. We demonstrate our model with an example.