  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
letter, we compute separately the contributions of the potential dense
rocky/icy core and 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. In the case of Jupiter and Saturn-like
planets, we show that the viscoelastic dissipation in the core could dominate
the turbulent friction acting on tidal inertial waves in the envelope. However,
the fluid dissipation would not be negligible. This demonstrates that it is
necessary to build complete models of tidal dissipation in planetary interiors
from their deep interior to their surface without any arbitrary a-priori.
