Adaptation of Real-time Temporal Resolution for Bitrate Estimates in IPFIX Systems

Packet sampling can greatly reduce traffic measurement overhead in high-speed broadband networks. At the same time, this operation introduces estimation errors that have to be carefully handled to ensure a reasonable measurement accuracy. Recently, a frequency-based approach has been proposed to catch the impact of such errors in bitrate estimation of a generic IP traffic flow, binned at both small and high time-scales. In particular, a closed-form expression for the signal-to-noise ratio has been derived as a function of the packet sampling probability, the bin size, and some basic information about the flow (i.e., first and second order moments of the packet size, and long term average packet-rate). In this work, we adopt such a model to design a real-time algorithm, that sets the IPFIX counter export timers in order to grant, to each flow, a target estimation accuracy. Computer simulations carried out using real packet traces have demonstrated the effectiveness of the proposed approach.