The current density integration in integrated circuits can have quite complex SoCs. Problems of interconnections between IP blocks become a critical point that current communication structures are no longer able to solve. These problems are mainly related to the notion of QoS becomes an important concept ensuring maximum reliability. Thus, solutions based NoC offer good prospects to overcome the current limitations of particular topologies Bus. NoC then constitutes a new paradigm for interconnecting SoCs. Through this paper, we tested four NoC topologies in different simulations with NS-2. Through metrics evaluated we were able to identify a selective classification of these topologies.