SUSIE - Charging and Accounting for QoS-enhanced IP Multicast

We developed a reference model for classifying charging, accounting and closely related processes, and for describing their interaction (see Figure 1). At the right, five layers are shown that encompass processing for charging and accounting. A configuration plane allows for providing configuration parameters for the processing layers. The configuration can be done on-line using signalling, as for Integrated Services, or off-line using management tools, as for Differentiated Services. Configuration parameters are derived from pricing policy, accounting policy and metering policy. These policies are provided by interaction of dedicated servers with the corresponding entities of the configuration plane. The metering layer performs metering of resource usage. Metering must allow to distinguish the two types of network resource: reservation of network resources, and actual usage of network resources. This distinction is useful as resources that are reserved but not used by a user may be offered to a different user, but usually under different conditions (lower price). Charging schemes may reflect this difference, e.g. by charging separately for reservation, and for actual usage. In case of multicast, depending on the cost sharing schemes, the meters can be placed at the edge routers only or also at the splitting points. The meter reader layer encompasses functional entities that access data provided by metering entities and forwards it for further processing to the Accounting Processing Layer. For supporting multicast charging, this layer is also responsible for selection of appropriate meters (meter placement). Transfer of metering data to the meter reader can be initiated explicitly (the meter reader initiates transfer of metering data) or implicitly (after a triggering event such as detection of a new flow, the meter initiates transfer of metering data to the meter reader). Entities of the accounting processing layer process usage data collected by meter readers, try to consolidate them based on service parameters and create accounting data sets (i.e., accounting records) which will be passed to the charging layer for pricing assignment. For supporting multicast charging, this layer is also responsible for reconstructing the multicast topology including splitting points where required by the cost sharing scheme. Additionally, the layer is also responsible for distributing collected usage data to other domains in a multi-provider environment. The charging layer derives costs for accounting data sets based on service specific tariffing parameters. Different cost metrics may be applied to the same usage of resources, and may be evaluated in parallel. A detailed evaluation of the resource usage can be used for generating bills to the customer, or for internal analysis (auditing) by the service provider. A simple evaluation of current costs can be used for displaying an estimation of accumulated costs for the service user, or for control purposes by the customer organisation or by the provider. For charging of multicast services, cost allocation assigns costs to specific endpoints, such as sender(s) and receivers of a multicast group.