In commercial network environments accounting is a main task besides e.g., network management, network planing, and charging, where accounting determines the collection and aggregation of information on service consumption, resource usage, and system activities. Accounting data can be used for various purposes, like charging the user for service consumption, collecting traffic traces for network management and traffic analysis, or deriving traffic characteristics for trend analysis and capacity planning.With the evolution and the increasing number of IP-based services, accounting needs to evolve from the traditional network-oriented view towards a service-oriented approach in a more dynamic environment, where new services can be launched in short time, where users use different end-devices, and where users are mobile across heterogeneous access networks. However, current IP accounting architectures do not fulfill all these requirements. They usually consider only access and network layer services and cannot efficiently cope with a highly dynamic environment, which is mainly due to the pre-defined and static configuration of the accounting process and the lack of mobility awareness.