Charging Multi-dimensional QoS with the Cumulus Pricing Scheme

The recently established Cumulus Pricing Scheme (CPS) has turned out to be a novel approach for efficiently charging differentiated Internet services, based on integrating different time-scales into one edge-pricing mechanism. Depending on an initial specification of expected resource requirements, customer and provider negotiate a contract fixing a flat rate charge for QoS delivery. As soon as the scheme has started, the customer receives a continuous coarse-grained feedback about her real resource consumption. To this end, overor underutilization are expressed in terms of Cumulus Points CP, whose accumulation may indicate an imbalance between specified and actually monitored traffic and eventually requires to adapt the contract accordingly. This paper extends the original CPS for services that are characterized not only by their bandwidth or volume requirements, but by general QoS parameters. Starting with a discussion on CPS for different one-dimensional QoS parameters, consequences for the basic CPS mechanism are investigated, covering especially the determination of relevant thresholds for CPs. These investigations deliver crucial input for the specification of multi-dimensional QoS vectors within the initial contract. Suitable metrics are introduced and applied in order to reduce the complexity of the contract as well as of the different monitoring methods. Finally, the implementation of the extended scheme within an Internet Charging System is discussed.