For the following I assume that the CMB is actually a highly redshifted image of the inner surface of the event horizon of our universe, which is a black hole. Secondly I assume that the universe actually consists of many, possibly infinite, nested black holes - black holes within black holes. Since it has been shown that the velocity of the earth can induce a doppler effect in the observed CMB, then the CMB may be considered an absolute reference frame for the measurement of velocity within our universe.

When the anisotropy caused by Earth's movement has been cancelled analytically the CMB is highly uniform, varying by only one part in a thousand. Consider the possibility that any remaining anisotropies are due to the superimposed effects of relative velocities of our universe within its parent universe, in turn having a velocity within its parent universe, et cetera.

This might lead to a testable hypothesis for a common generating mechanism of a nested multiverse, and its extent.