  We provide a semiclassical description of the electronic transport through
graphene n-p junctions in the quantum Hall regime. This framework is known to
experimentally exhibit conductance plateaus whose origin is still not fully
understood. In the magnetic regime (E < vF B), we show the conductance of
excited states is essentially zero, while that of the ground state depends on
the boundary conditions considered at the edge of the sample. In the electric
regime (E > vF B), for a step-like electrostatic potential (abrupt on the scale
of the magnetic length), we derive a semiclassical approximation for the
conductance in terms of the various snake-like trajectories at the interface of
the junction. For a symmetric configuration, the general result can be
recovered using a simple scattering approach, providing a transparent analysis
of the problem under study. We thoroughly discuss the semiclassical predicted
behavior for the conductance and conclude that any approach using fully
phase-coherent electrons will hardly account for the experimentally observed
plateaus.
