  Cosmological observations and cold dark matter N-body simulations indicate
that our Universe is populated by numerous halos, where dark matter particles
annihilate, potentially producing Standard Model particles. In this paper we
calculate the contribution to the diffuse neutrino background from dark matter
annihilations in halos at all redshifts and we estimate the future sensitivity
to the annihilation cross section of neutrino telescopes such as IceCube or
ANTARES. We consider various parametrizations to describe the internal halo
properties and for the halo mass function in order to bracket the theoretical
uncertainty in the limits from the modeling of the cosmological annihilation
flux. We find that observations of the cosmic diffuse neutrino flux at large
angular distances from the galactic center lead to constraints on the dark
matter annihilation cross section which are complementary to (and for some
extrapolations of the astrophysical parameters, better than) those stemming
from observations of the Milky Way halo, especially for neutrino telescopes not
pointing directly to the Milky Way center, as is the case of IceCube.
