The rheological behavior of a non-Brownian Newtonian concentrated suspension is investigated under
oscillatory shear at different strain amplitudes and at two frequencies. The data are in agreement with the literature
showing that the complex viscosity varies both with the number of oscillations imposed to the material and with the strain
amplitude. We here also show that the response to the oscillatory shear depends on the applied frequency. This result is
unexpected for a Newtonian suspension and implies the existence of some mechanism able to introduce a characteristic
time into the system. Can it be cage elasticity