Charging and Accounting for QoS-Enhanced IP Multicast

In this paper we propose a layered framework for charging QoS-enhanced IP services with policy based configuration of its layers. As an example architecture we present our implementation Value Added IP Charging and Accounting Service (VIPCAS). We further concentrate on VIPCAS elements for policies and data exchange. As flexible data structure for exchange of accounting information, we propose the Premium IP Network Accounting Record (PIP-NAR), which is suitable for a variety of charging schemes (e.g. charging of reserved and used resources), and which also makes providerspecific extensions possible. We specify the Tariff Formula Language (TFL) for representing tariff policies, and the Charging Information Protocol (CIP) for distributing tariff information expressed in TFL. For a fair charging of IP Multicast services, cost sharing functions should be supported at both the accounting and the charging layer. We evaluate different approaches in this area which support receiver heterogeneity with regard to the reserved QoS.