  We discuss the spectrum of the different components in the astrophysical
neutrino flux reaching the Earth and the possible contribution of each
component to the high-energy IceCube data. We show that the diffuse flux from
cosmic ray interactions with gas in our galaxy implies just 2 events among the
54 event sample. We argue that the neutrino flux from cosmic ray interactions
in the intergalactic (intracluster) space depends critically on the transport
parameter $\delta$ describing the energy dependence in the diffusion
coefficient of galactic cosmic rays. Our analysis motivates a E^{-2.1} neutrino
spectrum with a drop at PeV energies that fits well the data, including the
non-observation of the Glashow resonance at 6.3 PeV. We also show that a cosmic
ray flux described by an unbroken power law may produce a neutrino flux with
interesting spectral features (bumps and breaks) related to changes in the
cosmic ray composition.
