Impact of tariff on dial-up internet traffic: Modelling the subscriber response as a dynamic system

This paper contributes by providing a linear differential equation which captures the response of residential dial-up subscribers to a tariff function. South African data was gathered on residential subscribers who were making use of cheaper off-peak rates for dial-up Internet service outside business hours. Traffic intensity was found to be heavily dependent on the call tariff, with the steepest increase in traffic occurring at the time of rate changeover. It was also unexpectedly found that the traffic intensity dropped off exponentially as subscribers completed their tasks. The subscribers' response to a tariff change was then treated as a dynamic system, with input x(t) being the excitation function, representing the tariff imposed by the single network operator, and an output y(t), to represent the function of the traffic resulting from the imposed tariff. The response to the sudden tariff decrease was thus captured in a linear differential equation. Using the equation, the subscribers' response to a set of interesting tariff scenarios has been predicted. As a result, recommendations for superior tariffing are made.