Parlay X is a set of Web Service interfaces. These interfaces are designed to provide open access to telecommunication network functions in order to hide underlying network technology, and its control protocol complexity, from application developers. The Parlay X “intelligence” is concentrated in a node called Parlay X Gateway which converts interfaces methods in protocol messages and vice versa. An inherent constraint on any implementation requires the Parlay X Gateway to govern the interface to the underlying network i.e., to provide a single point of contact at which vertical signaling is received from the network. This chapter presents a study on alternatives for Parlay X Web Service deployment in Internet Protocol based multimedia networks (IMS). The focus is set on Parlay X Web Services for application-driven quality of service (QoS) management and charging control. It is presented as an analysis of the interfaces. Particularly the discussion is about their applicability to Policy and Charging Control architecture in IMS. Going further, the Web Service interfaces are mapped onto network protocols that they affect, namely Session Initiation Protocol (SIP) and Diameter. On that base an improvement is suggested concerning Parlay X interfaces for QoS management without violating the specified interface functionality. The usage of Web Services is exemplified with an application for charging control based on the provided QoS.
A user perspective for end-to-end quality of service evaluation in multimedia networks
