  TeV size extra dimensions introduce domain walls. Such walls are inconsistent
with CMB anisotropies. Either inflationary dynamics washes them out, or the
reheating temperature is lower then the temperature at which the walls start
forming networks. As the restoration of the symmetry is non-perturbative we
have performed 5d lattice simulations which show the occurrence of a cut-off in
the fifth dimension as well as symmetry restoration.
