  We present an analysis of normal and inverted hierarchical neutrino mass
models within the framework of tri-bi-maximal (TBM) mixing. Considering the
neutrinos to be quasi-degenerate (QDN), we study two different neutrino mass
models with mass eigenvalues $(m_1, -m_2, m_3)$ and $(m_1, m_2, m_3)$ for both
normal hierarchical (NH) and inverted hierarchical (IH) cases. Parameterizing
the neutrino mass matrix using best fit oscillation and cosmology data for a
QDN scenario, we find the right-handed Majorana mass matrix using type I seesaw
formula for two types of Dirac neutrino mass matrices: charged lepton (CL) type
and up quark (UQ) type. Incorporating the presence of type II seesaw term which
arises naturally in generic left-right symmetric models (LRSM) along with type
I term, we compare the predictions for neutrino mass parameters with the
experimental values. Within such a framework and incorporating both oscillation
as well as cosmology data, we show that QDN scenario of neutrino masses can
still survive in nature with some minor exceptions. A viable extension of the
standard model with an abelian gauged flavor symmetry is briefly discussed
which can give rise to the desired structure of the Dirac and Majorana mass
matrices.
