Live streaming applications are increasing on the Internet. These applications are delay sensitive and need group communication. Presently, protocols designed for this kind of communication do not rely on the classical client/server model used in the Internet but organize the receivers into an overlay network, where they are supposed to collaborate with each other following the peer-to-peer model. Live p2p streaming protocols can be classified in three different categories: source-driven, receiver-driven and datadriven protocols. Each of them manages the overlay differently. In this paper we compare them by simulation to specify what is the most appropriate approach for these protocols. We implement a new simulator of p2p network and we choose two well-known protocols for simulations: a sourcedriven and a data-driven protocol. To our knowledge, our works are the first to compare with the same simulator and scenarii different approaches for live p2p streaming. Our simulations show that nodes organization on the overlay influences drastically network global performances, and data-driven approach seems to be the most appropriate approach for these protocols because it is less sensitive to dynamicity of nodes which is the main problem to resolve for these applications.