  Tidal dissipation in planetary interiors is one of the key physical
mechanisms that drive the evolution of star-planet and planet-moon systems. New
constraints are now obtained both in the Solar and exoplanetary systems. Tidal
dissipation in planets is intrinsically related to their internal structure. In
particular, fluid and solid layers behave differently under tidal forcing.
Therefore, their respective dissipation reservoirs have to be compared. In this
work, we compute separately the contributions of the potential dense rocky/icy
core and of the convective fluid envelope of gaseous giant planets, as a
function of core size and mass. We then compare the associated dissipation
reservoirs, by evaluating the frequency-average of the imaginary part of the
Love numbers $k^2_2$ in each region. We demonstrate that in general both
mechanisms must be taken into account.
