%0 Journal Article %T Parlay X Web Services for Policy and Charging Control in Multimedia Networks %A Ivaylo Atanasov %A Evelina Pencheva %A Dora Marinska %J Advances in Multimedia %D 2012 %I Hindawi Publishing Corporation %R 10.1155/2012/296234 %X The paper investigates the capabilities of Parlay X Web Services for Policy and Charging Control (PCC) in managing all Internet-protocol-based multimedia networks (IMSs). PCC is one of the core features of evolved packet networks. It comprises flow-based charging including charging control and online credit control, gating control, and Quality of Service (QoS) control. Based on the analysis of requirements for PCC, the functionality for open access to QoS management and advanced charging is identified. Parlay X Web Services are evaluated for the support of PCC, and some enhancements are suggested. Implementation aspects are discussed, and Parlay X interfaces are mapped onto IMS control protocols. Use cases of Parlay X Web Services for PCC are presented. 1. Introduction IMS stands for internet protocol multimedia subsystem which is an architectural framework for service delivery in evolved packet networks. IMS enables various types of multimedia services based on access independency and IP connectivity [1]. The main requirement for IMS in conjunction with IP connectivity access network (IP-CAN) is to provide quality of service. Quality of service (QoS) is used to differentiate multimedia offering from traditional Internet services, which in most cases do not provide QoS. In order to provide a mechanism for service-aware QoS control and coherent charging, the Policy and Charging Control architecture is standardized. The Policy and Charging Control (PCC) is a key concept in IMS architecture and it is designed to enable flow-based charging, including, for example, online credit control, as well as policy control, which includes support for service authorization and QoS management [2]. In IMS, the user equipment negotiates with the network the session parameters by means of Session Initiation Protocol (SIP) signaling [3]. The service-related information is delivered to PCC functional entities and is used to form authorized IP QoS data (e.g., maximum bandwidth and QoS class) and charging rules as well as user plane event reporting (e.g., bearer loss recovery, access network change, and out of credit) for any access network [4]. To stimulate service provisioning and to allow applications outside of the network operator domain to invoke communication functions, an approach to opening the network interfaces is developed [5]. The open access to network functions allows 3rd party applications to make use of network functionality and to receive information from the network through application programming interfaces (APIs). Parlay X Web Services are highly %U http://www.hindawi.com/journals/am/2012/296234/