Epidemic-style diffusion schemes have been previously proposed for achieving
peer-to-peer live streaming. Their performance trade-offs have been deeply
analyzed for homogeneous systems, where all peers have the same upload
capacity. However, epidemic schemes designed for heterogeneous systems have not
been completely understood yet. In this report we focus on the peer selection
process and propose a generic model that encompasses a large class of
algorithms. The process is modeled as a combination of two functions, an aware
one and an agnostic one. By means of simulations, we analyze the
awareness-agnostism trade-offs on the peer selection process and the impact of
the source distribution policy in non-homogeneous networks. We highlight that
the early diffusion of a given chunk is crucial for its overall diffusion
performance, and a fairness trade-off arises between the performance of
heterogeneous peers, as a function of the level of awareness.