  We study the impact parameter dependence of inelasticity in the framework of
an updated geometrical model for multiplicity distribution. A formula in which
the inelasticity is related to the eikonal is obtained. This framework permits
a calculation of the multiplicity distributions as well as the inelasticity
once the eikonal function is given. Adopting a QCD inspired parametrization for
the eikonal, in which the gluon-gluon contribution dominates at high energy and
determines the asymptotic behavior of the cross sections, we find that the
inelasticity decreases as collision energy is increased. Our results predict
the KNO scaling violation observed at LHC energies by CMS Collaboration.
