  We report results on an ``one-way light path'' laser diffraction experiment
as a function of the laser beam alignment relative to the Earth's velocity
vector obtained by COBE measurements of the Doppler shift in the cosmic
microwave background radiation (CMBR). An amplified Doppler shift is observed
in the diffraction images, and the effect is compatible with a ``dipole'' speed
of light anisotropy due to Earth's motion relative to the ``CMBR rest frame'',
with an amplitude of $\delta c/\bar{c}=0.00123$. This amplitude coincides with
the value of the dipole temperature anisotropy $\delta T/\bar{T}=0.00123$ of
the CMBR obtained by COBE. Our results point out that it is not possible to
neglect the preferred frame imposed by the cosmology and they are well
described by the Ether Gauge Theory (an extension of the Lorentz's ether
theory) and it satisfies the cosmological time boundary condition.
