Fair ATM charging with consideration of traffic characteristics and QoS parameters

Today, public network providers perform usage-based charging of ATM services based on transmitted cells, allocated bandwidth, and connection time. Nevertheless, it is important being able to simplify the process of charging by considering the requested service category and the implied quality of service (QoS) that might be negotiated additionally. We present a charging framework and its application on representative services which is based on the following aspects. First, we differentiate five ATM service categories: constant bit rate (CBR), real-time variable bit rate (rt-VBR), nonreal-time variable bit rate (nrt-VRB), unspecified bit rate (UBR), and available bit rate (ABR). These categories are refined by traffic parameters. On this basis, we define the total cost of an ATM-connection by the sum of: the cost for the establishment of the connection; the cost for reservation of the connection (depending on the the chosen service class and depending on the traffic descriptors and QoS-parameters); and the usage-based costs. In order to allow fair charging in cases with nonnegligible error rates, we propose to allow a distinction of usage-based costs between actual goodput, redundant data used for forward error correction (FEC), and retransmitted data.