Interactions within Multi-agent systems can be structured in different ways depending on the application scenario and its environmental restrictions. In previous work we have developed a multi-agent system within a Peer-to-Peer (P2P) sharing data network scenario. Its design includes an organisation that structures agents' interactions and an abstract architecture (2-LAMA) that helps to improve its performance. The focus of this paper is to first characterise the environment of this scenario in terms of network topologies and, secondly, to study how it affects system's performance in relation to the proposed architecture. In order to do that, we have set up a series of experiments that consider different network topologies and evaluate their performance. Results show that our architecture effectively helps to improve system's performance in despite of physical network topology.