  We argue that an effective flavor discrimination in neutrino telescopes is
the key to probe the flavor ratios of astrophysical neutrinos at the source and
flavor transition mechanisms of these neutrinos during their propagations from
the source to the Earth. We first discuss how well one can reconstruct the
flavor ratios of astrophysical neutrinos at the source. We then discuss how to
probe flavor transition mechanisms of propagating astrophysical neutrinos. In
this regard, we propose a model independent parametrization for neutrino flavor
transitions, with the neutrino oscillation as a special case.
