(ISP). For example, a circuit-switched network provider charges different tariffs at different times of the day. It was noted that at the time that the rates decreased, the traffic intensity logged by the ISP increased dramatically and then decayed over time at an exponential rate. The conclusion of the research was that by varying prices over time, a telecommunications service provider can reduce the level of the traffic intensity at peak periods, resulting in lower equipment costs because of the reduced need to provision to meet peak demand, which in turn leads to increases in long-term revenue and profitability. See Time-based pricing. References Farr, R.E., Telecommunications Traffic, Tariffs and Costs - An Introduction For Managers, Peter Peregrinus Ltd, 1988. Kennedy I.G., "Why is Network Planning Important?", Lecture Notes, ELEN5007 - Teletraffic Engineering, School of Electrical and Information Engineering, University of the Witwatersrand, 2005. Further reading OECD, Universal Service and Rate Restructuring in Telecommunications, Organisation for Economic Co-operation and Development (OECD) Publishing, 1991. Telecommunications economics