  We start a systematic study of the Lema\^{i}tre-Tolman-Bondi (LTB) model as
applied to the large scale structure and its evolution. Here we study three
possible initial conditions of the LTB models which are asymptotically FRW at
large scales: bang time, fractal density (with fractal dimension D=2), and
velocity law. Any two of these determine the third one. Fractal density and
simultaneous bang time provide a quantitative estimate for the scale beyond
which the deflection from the linear Hubble law is small. This border may be
identified with the zero-velocity surface. For fractal density and linear
Hubble law it is shown that the bang time is necessarily non-simultaneous.
